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DISSERTATION

Presented in Partial Fulfillment of the Requirements for

the Degree Doctor of Philosophy in the Graduate

School of The Ohio State University

Beverly Swaim Gerdeman, M.S.

The Ohio State University 2002

Dissertation Committee: Approved by Assistant Professor Hans Klompen, Adviser

Associate Professor Dana Wrensch

Professor David Horn // /^Adviser Professor Emeritus Rodger Mitchell itomofogy Grad-

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission UMI Number 3039471

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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ABSTRACT

Narceoheterozercon ohioensis n. gen., n. sp. (Acari: Heterozerconidae) the first

North American representative of Heterozerconidae, is described. The description includes

the first immatures for the infraorder Heterozerconina. A new location for the secondary

genital opening in the Acari is discovered in the inner, anterior comer of the suckers in

females.

The phenology of a tropical heterozerconid provides a comparison for that in the

temperate climate. Both field studies and laboratory observations establish the biology and

ecology of Narceoheterozercon ohioensis. The phenology between the mites and their

millipede host, Narceus annularis (Diplopoda: Spirobolida) shows coinciding periods of

oviposition and mating. The three immature mite instars develop through the summer

beginning in June and continuing through August. Teneral adults appear in late August and

early September and males may briefly outnumber females. The mating millipedes may

provide a cross-species mating stimulus for their heterozerconid commensals. Evidence

suggests post-mating dispersal occurs in the millipedes. Mites appear to overwinter on

their hosts.

A hypothesis for the origin of the spermatodactyi on the fixed digit of the males is

proposed. The spermatodactyi appears to have evolved from structures associated with the

fixed digit, including the pilus dentilis. This indicates the spermatodactyi in the

Heterozerconina arose independently from that in the Dermanyssina.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. A world survey of spermatodactyls reveals an enormous diversity. The diversity

may be due to lengthening and fusing of structures associated with the fixed digit.

Differences in the appearance of the spermatodactyls allows them to be grouped into 4

major zoogeographic regions: African, Oriental, Neotropical and Nearctic. Characteristics

in the spermatodactyls of each region are discussed. The diversity in the spermatodactyls

suggests a variety of reproductive methods occur in the Heterozerconidae. Podospermy

appears present in all four zoogeographic regions. Evidence from the Oriental region

suggests a transition stage between tocospermy and podospermy may occur in the

Heterozerconidae.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Dedicated to the kingdoms of the hollow

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ACKNOWLEDGMENTS

I wish to thank my adviser, Hans Klompen, for sharing his enthusiasm in my

project and for his patience, intellectual support and willingness to listen to my ideas. I am

grateful to Rodger Mitchell for introducing me to the classical aspects of scientific writing

and illustration and for never running out of time. I also thank Dana Wrensch for

understanding and supporting the addition of a creative artistic approach to the logical

processes of scientific problems.

My sincere appreciation to my husband Robert, who never grew weary of the

words “millipede” and “heterozerconid", uttered at all times of the day and night and for

allowing me to pursue my goals. To my four daughters: Ana, Erikah, Mauria and Diedre

for their unwavering support and surviving on promises.

The tropical research was made possible through the support of the Fulbright

Association, The Institute of International Education and the Philippine American Education

Foundation. Thanks to Ms. Tessie Camero-Hawes, Leonila Raros and Mercedes

Delfinado-Baker for their support and enthusiasm during my stay in the Philippines. My

sincere gratitude to Phin Garcia for sharing his tropical collecting expertise and for having

the courage to guide me through the islands.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. VITA

July 14, 1952 ...... Born - Hot Springs, Arkansas

1996 ...... M.S. Entomology, The Ohio State University

1977 ...... B.S. Education, Henderson State University

1974 ...... B.S. Wildlife Management, Arkansas Tech College

1993-present ...... Graduate Teaching and Research Associate, The Ohio State University

PUBLICATIONS

Research Publication

1. Gerdeman, B.S., Klompen, J.S.H. and J.A. Yoder. 1999. Description of the larva of Gromphadorholaelaps schaeferi (Acari: Laelapidae) a parasite of the giant Madagascar hissing-cockroach. Int. J. Acarol., 24: 301-305.

2. Gerdeman, B.S., Klompen, J.H.S., and L. K. Tanigoshi. 2000. Insights into the biology of a mite/millipede association. In: Wytwer J. and S. Golovatch (eds.), Progress in Studies on Myriapoda and Onychophora. Fragm. faun., Warszawa 43:223-227.

FIELDS OF STUDY

Major Field: Entomology

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. TABLE OF CONTENTS

PACE Abstract ...... ii

Dedication ...... iv

Acknowledgments ...... v

Vita ...... vi

Table of Contents ...... vii

List of Tables ...... x

List of Figures ...... xi

Chapters:

1. Introduction ...... 1

2. A new North American heterozerconid, Narceoheterozercon ohioensis, n. gen., n. sp., with first description of immatures of Heterozerconidae (Acari: Mesostigmata) ...... 6

2.1 Introduction ...... 6 2.2 Materials and Methods ...... 8 2.2.1 Study Site ...... 8 2.2.2 Collecting and Rearing Techniques ...... 8 2.2.3 Material Examined...... 8

vii

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.2.4 Specimen Preparation and Measurements...... 10 2.2.5 Specimen Depositories ...... 10 2.3 Narceoheterozercon, n. gen...... 11 2.4 Narceoheterozercon ohioensis, n. sp...... 11 2.5 Description ...... 12 2.5.1 Gnathosoma ...... 12 2.5.2 Pedipalps ...... 14 2.5.3 Subcapitulum ...... 16 2.5.4 Tritosternum ...... 18 2.5.5 Gnathotectal process ...... 18 2.5.6 Idiosoma ...... 19 2.5.7 Legs ...... 23 2.6 Discussion ...... 26 2.6.1 Ventral suckers ...... 29 2.7 Acknowledgments ...... 30 2.8 List of References ...... 31

3. Life history of a North American heterozerconid, Narceoheterozercon ohioensis, with comparative data for a tropical species...... 55

3.1 Introduction ...... 55 3.2 Materials and Methods ...... 57 3.2.1 Field site ...... 57 3.2.2 Field and laboratory Techniques ...... 58 3.2.3 Tropical Field and laboratory Techniques...... 59 3.3 Results and Discussion ...... 60 3.3.1 Temperate Host Requirements ...... 60 3.3.2 Vegetation ...... 63 3.3.3 Tropical Phenology ...... 66 3.3.4 Invertebrate Community ...... 70 3.3.5 Interactions with the Host ...... 72 3.3.6 Tropical Phenology ...... 78 3.4 Conclusions ...... 80 3.5 Acknowledgments ...... 8

viii

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.6 List of References 82

4. Diversity of spermatodactyls and mating systems within the Heterozerconidae.. 88 4.1 Introduction ...... 88 4.2 Materials and Methods ...... 90 4.2.1 Collecting / Rearing techniques ...... 90 4.2.2 Specimen Study Techniques, Preparation and Measurements 91 4.2.3 Material Examined...... 91 4.2.3 Material Examined ...... 90 4.3 Results and Discussion ...... 92 4.3.1 The fixed Digit...... 95 4.3.2 The Fixed Digit ...... 94 4.3.3 Spermatodactyi Diversity in the Heterozerconidae...... 96 4.3.4 Diversity of Female Reproductive Systems in the Heterozerconidae ...... 99 4.4 Conclusion ...... 102 4.5 Acknowledgments ...... 104 4.6 List of References ...... 105 5. List of References ...... 113

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF TABLES

TABLE PAGE 3.1 Identifiable species of logs inhabited by Narceus annularis...... 62

3.2 “West-facing transect”. Four most prominent tree species...... 63

3.3 “Floodplain transect”. Four most prominent tree species...... 64

3.4 “East-facing transect”. Four most prominent tree species...... 64

3.5 Appearance and behavior differences between immatures and adult Narceoheterozercon ohioensis (Acari: Heterozerconidae) ...... 68

3.6 Comparisons in a tropical and temperate mite/millipede association...... 79

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF FIGURES

Figure Page

2.1 Narceoheterozercon ohioensis n. gen., n. sp. Chelicerae. A. larva, B. protonymph, C. deutonymph, D. female, E. male, (ce) ventral cheliceral envelope, (cp) comblike process, (mm) interdigital membranes, (pd) pilus dentilis...... 34

2.2 Narceoheterozercon ohioensis n. gen., n. sp. Immature pedipalps A. larva, B. larva palptibiotarsus, C. protonymph, D. protonymph palptibiotarsus, E. deutonymph , F. deutonymph palptibiotarsus. (re) rudimentary palptarsal claw, (rm) rudimentary membranous structure ...... 35

2.3 Narceoheterozercon ohioensis n. gen., n. sp. Adult pedipalps A. female, B. female palptarsus, C. male, (rm) rudimentary membranous structure ...... 36

2.4 Narceoheterozercon ohioensis n. gen., n. sp. Subcapitulum. A. larva, B. protonymph, C deutonymph, D.female, E.male. (co) comiculi, (cpt) cuticular points, (hp) hypostomal plateau, (im) internal malae, (la) labrum, (pi) paralaciniae, (sp) short spines, (ss) salivary stylus ...... 37

2.5 Narceoheterozercon ohioensis n. gen., n. sp. Tritostemum A. larva, B. protonymph, C. deutonymph, D. female, E. male...... 38

2.6 Narceoheterozercon ohioensis n. gen., n. sp. Gnathotectal process. A. larva, B. protonymph, C. deutonymph, D. female, E. male...... 39

2.7 Narceoheterozercon ohioensis n. gen., n. sp. Immature venters A. larva, B. protonymph C. deutonymph. (cag) coxal associated gland, (eg) exocrine glands ...... 41

2.8 Narceoheterozercon ohioensis n. gen., n. sp. Adult venters A. male, B. teneral female, C. mature female, (els) corrugated-like structures, (dc) denticulate cuticular fringe, (rs) reproductive structure, (s) variable postanal setae ...... 43

2.9 Narceoheterozercon ohioensis n. gen.,n. sp. Immature dorsum A. larva, B. protonymph, C. deutonymph ...... 45 x

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.10 Narceoheterozercon ohioensis n. gen., n. sp. Adult dorsum. A. male, B. teneral female, C. mature female, (sm) sucker muscle scars ...... 47

2.11 Narceoheterozercon ohioensis n. gen., n. sp. Immature legs. A. larva leg I, B. larva leg II, C. larva leg III, D. protonymph leg I V...... 49

2.12 Narceoheterozercon ohioensis n. gen., n. sp. Adult legs. A. male leg I (tarsus absent), B. male leg II, C. male leg m , D. male leg IV, E. trochanteral structure ...... 50

2.13 Narceoheterozercon ohioensis n. gen., n. sp. Tarsus I. A. larva, B. female partial tarsus/acrotarsus, C. male ...... 52

2.14 Narceoheterozercon ohioensis n. gen., n. sp. Female subcapituium. SEM ... 53

2.15 Narceoheterozercon ohioensis n. gen., n. sp. Female ventral sucker. SEM ... 54

2.16 Narceoheterozercon ohioensis n. gen., n. sp. Female ventral sucker. SEM ... 54

3.1 Narceoheterozercon ohioensis. Prevalence 1997-1999. Ohio, U SA 85

3.2 Intensity. Heterozerconidae adults/millipede. Philippines (2001), Ohio, USA (1999) ...... 86

3.3 Total numbers of Philippine immature Heterozerconidae/total samples/collecting date ...... 87

4.1 Discozercon sp. Australia. A. Discozerconidae chelicerae, B. fixed digit, (cs) curled structure, (pd) pilus dentilis ...... 106

4.2 African zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Cote d’Ivoire, B. Tanzania, C. Gabon, D. Central African Republic, E. Madagascar, (cs) curled structure, (pd) pilus dentilis...... 107

4.3 Oriental zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. India, B. Thailand, C. Thailand, D. Philippines, C. Malaysia, F. Borneo ...108

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 4.4 Neotropical zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Costa Rica, B. Brazil, C. Venezuela, D. Southern Mexico, E. Ecuador ...... 109

4.5 Nearctic zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Narceoheterozercon ohioensis, Ohio, USA. B. Heterozerconidae, Alabama, USA. C. Narceoheterozercon sp., Florida, USA ...... 110

4.6 Narceoheterozercon ohioensis. Male spermatodactyi strorage beneath dorsum ...... I l l

4.7 Narceoheterozercon ohioensis. Female secondary gential opening (sgo) and associated ducts ...... 111

4.8 Heterozerconidae female, coxa IV. Madagascar, (sp) spermatheca...... 112

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 1

INTRODUCTION

The family Heterozerconidae, a member of the infraorder Heterozerconina in the

order Mesostigmata, is presently comprised of two families, Heterozerconidae and

Discozerconidae. Both families are associated with myriapods. Discozerconidae is primarily associated with centipedes while members of Heterozerconidae have been

collected from litter, snakes, amphisbaenids, a termite mound, and bark of a tree but

primarily they are associates of millipedes. The Heterozerconina are mostly tropical but

heterozerconids (Narceoheterozercon ohioensis chapter 2) have been collected as far

north as Ohio, USA. Morphologically, both families are distinguished from other Acari by their peculiar

ventral suckers. In the Heterozerconidae, the suckers are present in the majority of species

and only during the adult stage when they are found on the millipedes.

Millipedes provide both food and a habitat for a large number of endoparasites and

ectoparasites. Narceus annularis (Diplopoda) utilizes decaying logs for nest sites (Chapter

3). Through repeated use, these nest sites accumulate large amounts of millipede frass

which attracts a diverse fauna. The combination of the millipede and its nest sites offers the

opportunity for associates to exploit both habitats, with each environment promoting its

own set of adaptations (Chapters 2,3).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Narceoheterozercon ohioensis is a commensal associate of Narceus annularis

(Diplopoda: Spirobolida). The heterozerconid association with millipedes, while obligate,

is not a full time association. The adults are found on the millipede and the immatures

develop in the accumulated frass (Chapter 3). Even though the immatures are not found on

millipedes they are dependent upon them for production of their habitat.

In Narceoheterozercon ohioensis, the exploitation of two different habitats has

resulted in immatures bearing little resemblance to the adults (Chapter 2). This has

hampered attempts to adequately describe the immatures. In addition, the adults occur on

an animal which is also seldom studied. These problems are reflected in the small numbers

of described genera and species.

Currently the Heterozerconidae is represented by only six described genera:

Afroheterozercon, Allozercon, Asioheterozercon, Heterozercon, Maracazercon, and

Zeterohercon. A historical review of the Heterozerconidae based on Fain (1989) follows:

1. Heterozercon degeneratus Berlese, 1888

Mato Grosso, Brazil; ex: under bark of tree (Berlese, 1888)

2. Heterozercon latus Berlese, 1901

Tacuru Pucu, Paraguay; ex: nest of Anoplotermitis pacifici (Isoptera) (Berlese

1901; Silvestri, 1904)

3. Heterozercon cautus Berlese, 1923

East Africa; collecting data unknown (Berlese, 1923)

4. Heterozercon microsuctus Fain, 1989

Ilha da Maracas, N. Brazil; ex: Spirostreptus sp. (Diplopoda) (Fain, 1989)

5. Allozercon fecundissimus Vitzthum, 1926

Buitenzorg, Java; ex: soil (Vitzthum, 1926)

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 6. Asioheterozercon audax (Berlese, 1910) (= Heterozercon audax Berlese)

(= Heterozercon elapsus Vitzthum)

Java, ex: Scolopendra sp. (Chilopoda),Spirostreptus sp.(Diplopoda) (Berlese,

1910); Sumatra, ex: Thyropygus sp. (Diplopoda: Spirostreptoidea) (Vitzthum,

1925)

7. Afroheterozercon spirostreptus Fain, 1989

Mayumbe forest, Zaire; ex: Spirostreptus comutus (Diplopoda: Spirostreptidae)

(Fain, 1989)

8. Afroheterozercon pachybolus (Fain, 1989), (= Heterozercon pachybolus. Fain)

Kwango River, Zaire; ex: Pachybolus macrostemus (Diplopoda) (Fain, 1988;

1989)

9. Afroheterozercon ancoratus Fain, 1989

Near river Luki, Mayumbe forest, Bas-Zai're, Zaire; ex: nest of termites

(Cubitermes) (Fain, 1989)

10. Maracazercon jolivetti Fain, 1989

Ilha da Maracas, Brazil; ex: Spirostreptus (Diplopoda) (Fain, 1989)

11. Zeterohercon amphisbaenae Flechtmann and Johnston, 1990

Sao Paulo, Brazil; ex: Amphisbaena alba Linnaeus (worm lizard)

(Flechtmann and Johnston, 1990)

12. Zeterohercon oudemansi (Finnegan, 1931) (= Heterozercon oudemansi Finnegan),

Upper Amazon, Brazil; ex:Epicrates cinchris (Serpentes: Boidae) (Flechtmann

and Johnston, 1990)

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 13. Zeterohercon elegans (Lizaso, 1979) (= Heterozercon elegans, Lizaso)

Brazil; ex: Waglerophis merremii, Mastigodryas bifossatus,

Erythrolamprus aesculapii (Serpentes) (Lizaso, 1979)

In this study, a worldwide survey of specimens has revealed a substantial number

of undescribed species. This is indicated by the differences observed in morphology of the

male sperm transfer devices, the spermatodactyls. A hypothesis regarding the origin of the

spermatodactyls (Chapter 4) sheds new light on the relationship between the

Heterozerconidae and the other suborder possessing spermatodactyls, the Dermanyssina.

This hypothesis also allows a comparative analysis of the spermatodactyls and their

subsequent placement into 4 major zoogeographic regions.

Accompanying the diversity in the male are differences in reproductive methods.

Podospermy, or spermatophore deposition into a secondary genital opening, is represented

in all 4 zoogeographic regions. Some evidence also suggests that a transition between

tocospermy and podospermy may occur in the Heterozerconidae (Chapter 4).

The “The Biology of the Heterozerconidae”, is divided into three chapters. Chapter

2, "A new North American heterozerconid, Narceoheterozercon ohioensis, n. gen., n.

sp. with first description of immatures of Heterozerconidae (Acari: Mesostigmata)”, is the

first description of a North American heterozerconid and includes the first detailed

description of immatures of the infraorder Heterozerconina.

Both field and laboratory data collected over a period of three years as well as data

collected in the Philippines, are presented in Chapter 3, “Life history of a North American

heterozerconid, Narceoheterozercon ohioensis with comparative data for a tropical

species”.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Chapter 4, “Diversity of spermatodactyls and mating systems in the

Heterozerconidae”, is based on laboratory observations of mating and Held collections of

heterozerconids by the author in the United States and the Philippines, as well as specimens

on loan from other institutions.

There are four primary goals in this study:

1. To develop a basic understanding of the life history and intricate relationship between

the mite and its associated millipede through Held and laboratory observations.

2. To describe a new genus of North American Heterozerconidae, Narceoheterozercon,

including first records for immatures within Heterozerconina.

3. To hypothesize an origin for the heterozerconid spermatodactyi and place them into

geographical groups based on appearance.

4. To present a biogeographical analysis of these major groupings of world taxa,

demonstrate their regionality, and in the process, showcase the morphological

diversity in the Heterozerconidae.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 2

A New North American Heterozerconid,

Narceoheterozercon ohioensis, n. gen., n. sp.,

With First Description of Immatures of

Heterozerconidae (Acari: Mesostigmata)

2.1 INTRODUCTION

Ontogenic homologies often provide crucial evidence securing phylogenetic

placement. Knowledge of the basic patterns of ontogenic development for a group, allows

broad comparisons among distant groups of arthropods. For instance, members of the

Acari share a hexapod larva with Ricinulei. Within the Acari, knowledge of the immature

stages provides the basis for many of the hierarchical levels of classification. In the case of

Astigmata, presence of a specialized deutonymph for dispersal is a characteristic of the

suborder. In Mesostigmata, members of Uropodina are classified among other things, on

dorsal sclerotization of the immatures. Relationships that are not obvious in adults can be

discovered through comparison of immature characters secondarily lost in adults. For

example, a postanal seta is present in the larval instar of Trigynaspida, but disappears in the

adults (Lindquist, 1984). Knowledge of specific developmental patterns therefore may

provide clues to the evolution of a particular group (Lindquist, 1984).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Lack of knowledge of full ontogenies invites taxonomic errors and complicates the

establishment of chaetotactic homologies for comparison with other groups. Within

Acariformes, it is the adults that are often unknown. In Parasitengona and Astigmata,

taxonomic keys are often based on the only instar available, usually the larva and

deutonymph, respectively. In these cases it suffices taxonomically but there is no doubt

that a full ontogenetic series would provide further clues to their evolutionary past.

Full ontogenies within the suborder Mesostigmata are well known except for some of the

more aberrant groups (Krantz, 1978). With the exception of groups possessing phoretic

deutonymphs, such as Uropodina and Sejina, it is the immatures that are most often

unknown.

Heterozerconidae is a member of the suborder, Mesostigmata. Heterozerconids are

primarily known from their associations with millipedes and their possession of large

ventral suckers. Since their discovery in 1888 (Berlese, 1888), there have been no

descriptions of immature instars. As a result, their phylogenetic position has remained

inconclusive and they are for the most part, a forgotten group.

During the course of this study, immature heterozerconids were discovered off the

host in accumulations of millipede frass, beneath the bark of downed trees (Gerdeman et

al., 1999). This study represents the first description of immatures for the entire suborder

Heterozerconina. The goal of this paper is to provide a useful working description of

immature heterozerconids. It is also hoped to generate interest in some of the lesser known

groups within Mesostigmata.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.2 MATERIALS AND METHODS

2.2.7 Study Site The study site is located in Little Rocky Hollow, near Gibisonville, in

Hocking County, Ohio, U.S.A., 39° 28’59”N, 82°50’5 rW . Little Rocky Hollow lies in

the unglaciated “Hocking Hills” region of southeast Ohio. Situated at the leading edge of a

Wisconsin glacier, the cliffs and gorges provide a suitable microclimate for a mixed

hardwood forest and for those taxa requiring a long-term stable environment. Most of the

original vegetation has been modified through cutting, with perhaps only small pockets

escaping. One section was logged as recently as 1971 (Jeff Johnson, pers. comm.). On

January 22, 1981, Little Rocky Hollow became the 44th state nature preserve. Since then,

access is by permit only, protecting the site. Most of the assumed original vegetation has

recovered, with the exception of species affected by natural diseases such as the American

chestnut, Castanea dentata (Marshall) Borkhausen, once one of the dominant species.

2.2.2 Collecting and Rearing Techniques Adult mites were recovered from field collected

millipedes, Narceus annularis (Rafinesque). The millipedes were identified using the

morphometric formula presented by Keeton (1960). Voucher specimens are deposited in

the Acarology Laboratory, Ohio State University, Columbus, Ohio (OSAL). Immature

mites were primarily obtained from laboratory cultures with few field collections. In the

laboratory, cultures were maintained in plastic containers on a substrate of milled

sphagnum moss.

2.2.3 Material Examined USA, Ohio, Hocking County, Little Rocky Hollow, 39°

28’59”N, 82°50’51”W; 24-DC-99, OSAL 006440, Holotype female. Paratypes: Same

locality, 14-V-98, OSAL 005520 (IF); 14-Vffl-98, OSAL 005548 (IF); OSAL 005590

(IF); OSAL 005592 ( 1M, IF); OSAL 005594 (IF); OSAL 005595 (IF); OSAL005593

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (1M); 18-IX-98, OSAL 005597 (IF); OSAL 005598 (IF); 16-Vm-99, OSAL 006429

(IF); 2-DC-99, OSAL 006431 (IF); 23-DC-99, OSAL 006430 (IF); 24-IX-99, OSAL

006432 (1M, IF); OSAL 006433 (IF); OSAL 006435 (1M, IF); OSAL 006441 (IF);

OSAL006445 (IF); OSAL 006475 (IF); OSAL006476 (IF); 7-X-99, OSAL006444

(IF); 29-Vm-OO, OSAL 006452 (1M); OSAL 006454 (IF); 14-IX-00, OSAL006461

(IF); OSAL 006462 ( 1M). 12-IX-97, OSAL 005432 (1M); 19-Vm-98, OSAL005547

(1M); 18-IX-98, OSAL 005598 (1M); 19-IH-99, OSAL 005687 (lM);24-DC-99, OSAL

006437 (1M); OSAL 006438 (1M); OSAL 006455 (1M); OSAL 006456 (1M); 6-IX-00,

OSAL 006453 (1M); Laboratory cultures (origin Little Rocky Hollow): 30-X-97, OSAL

005331 (IF); 6-XI-97, OSAL005332 (IF); 9-VI-98, OSAL005525 (IF); 2-XI-99, OSAL

006446 (IF); OSAL 006447 (1M); 25-VI-97, BSG97-0625-4 (lLv); 21-VII-97, OSAL

005222 (ILv); 22-VID-97, OSAL005313 (lLv); 14-X-97, OSAL005328 (lLv); OSAL

005329 (lLv); 3-IV-98, BSG98-0403-4 (ILv); 27-VDI-98, BSG98-0827-8 (ILv); 2-DC-

98, BSG98-0902-28 (ILv); 1 l-IX-98, BSG98-0911-1 (ILv); BSG98-0911-10 (ILv); 14-

XII-98, OSAL 005603 (3Lv); 7-1-00, BSG00-0107-2 (ILv); BSG00-0107-2AA (ILv,

lPn); BSGOO-0107-2 (lPn); BSG0O-O1O7-2A (lPn); BSG00-0107-2B (lPn);BSG00-

0107-2C (lPn); BSG00-0107-2D (lPn); BSGOO-0107-2E (lPn); BSGOO-0107-2F (lPn);

BSGOO-0107-2J (lPn); BSG00-0107-2K (lPn); BSGOO-0107-2BB (1 pn); 22-IX-OO,

OSAL006469 (ILv); 22-Vffl-97, OSAL 005314 (lPn); 13-X-97, OSAL 005327 (lDn);

10-VH-98, OSAL 005529 (lDn); 3-X-00, OSAL 006471 (lDn). USA Ohio, Hocking

County, Sheick Hollow, paratypes 26-V-98, OSAL 005521 (IF); 20-V-99, OSAL 005790

(IF). USA Ohio, Pickaway County, Tar Hollow State Park, paratypes 11-IX-97, OSAL

005319 (1M, IF). USA, Ohio, Vinton County, USFS Vinton Furnace, paratype 19-111-

99, OSAL 005687 (IF).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.2.4 Specimen Preparation and Measurements Specimens were cleared in lactophenol

and mounted in Hoyer’s medium on microscope slides (Krantz, 1978). Specimens were

studied with phase contrast and differential interference contrast systems. Descriptive

drawings were made with a camera-lucida on a Zeiss Axioskop compound microscope.

Measurements were made with an ocular measuring lens and converted to micrometers

(|im). All measurements are presented in micrometers (|xm) in the format average (range).

Unless otherwise noted, averages represent the following numbers of specimens: 10

larvae, 10 protonymphs, 7 deutonymphs, 8 teneral females, 2 mature females, and 10

males. Ventral idiosomal lengths were measured from the base of the gnathosoma to the

end of the opisthosoma. Idiosomal widths were measured at the broadest point.

Idiosomal chaetotaxy generally follows the system of Lindquist and Evans (1965),

with modifications for the caudal region as given by Lindquist (1994) and Lindquist and

Moraza (1998). Setal nomenclature for non-tarsal leg segments follows Evans (1963a), for

tarsi D-IV Evans (1967), and for the pedipaips Evans (1963b). Poroidotaxy and adenotaxy

is based on Johnston and Moraza (1991). Sigillotaxy follows Athias-Henriot (1975).

Designations for gnathosomal structures follow Alberti and Coons (1999).

2.2.5 Specimen Depositories Holotype in the Acarology laboratory, The Ohio State

University (OSAL). Specimens have been deposited in the following institutions:

Acarology Collection in the Department of Entomology and Plant Pathology, Auburn

University, Auburn, Alabama (AUEM); Bayerische Julius-Maxilimians-Universitat

Wurzburg (Theodor-Boveri-Institut fur Biowissenschaften, Tierokologie &

Tropenbiologie), Wurzburg, Germany; The British Museum of Natural History, London,

U.K. (BMNH); Canadian National Collection of Insects, Ottawa, Canada (CNC); Field

Museum of Natural History, Chicago, Illinois (FMNH); Institut royal des Sciences

Naturelles de Belgique, Bruxelles, Belgium (ISNB); National Museum of Natural History,

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Washington, D.C. (NMNH); Acarology Laboratory, Ohio State University, Columbus,

Ohio (OSAL); Universidade de Sao Paulo, ESALQ Piracicaba, Sao Paulo, Brasil;

University of Michigan Museum of Zoology, Ann Arbor, Michigan (UMMZ); University

of the Philippines, Los Banos, Philippines (UPPC).

2.3 Narceoheterozercon, n. gen.

DIAGNOSIS - Female with prominent, well sclerotized, solenostomes arching anteriorly

from the inside upper comer of the sucker-like structures (Figs. 8B, C). Male with long,

recurved, and largely smooth spermatodactyl. Prominent spines on legs II absent. Adults

lack spine-like marginal setae on opisthosoma.

Type species: Narceoheterozercon ohioensis n. sp.

2.4 Narceoheterozercon ohioensis, n. sp.

DIAGNOSIS - In addition to the characteristics of the genus, with sexually dimorphic

gnathotectum. Gnathotectal process sexually dimorphic. Tongue-like with a smooth edge

in the female, triangular with 3 anterior projections and overlapping denticulate layers in the

male.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.5 DESCRIPTION

2.5.1 GNATHOSOMA

Chelicerae

Larva (Fig. 2.1 A). Three segmented, basal segment slightly shorter that fixed digit.

Entire cheliceral length 130(118-159). Shaft, equal in diameter throughout. Movable digit

length 48 (43-53), fixed digit length 38 (34-38). Fixed digit bidentate, teeth adjacent,

positioned in basal half of digit. Large pilus dentilis (pd) at level of teeth near middle of

fixed digit. Antiaxial face with dorsal seta,ds (Fig. 2. IB), at base of digit. Lyrifissure id

not visible. Lyrifissure ia at base of fixed digit. Interdigital membranes fimbriate.

Movable digit edentate with medially located membranous comblike process (cp). Ventral

cheliceral envelope (Fig. 2.1C: ce) narrow, straplike, composed of two elements; inserted

approximately at the midpoint on the ventro-lateral side of movable digit.

Protonymph (Fig. 2.IB). Cheliceral length 209 (187-232). Movable digit length 64 (56-

67), fixed digit length 54 (49-60). Lyrifissure id situated near dorsal seta ds. Otherwise,

as in larva.

Deutonymph (Fig. 2.1C). Cheliceral length 284 (271-300). Movable digit length 82 (77-

90), fixed digit length 89 (85-94). In other aspects, as in larva.

Female (Fig. 2.ID). Segments as in previous instars. Cheliceral length 278 (269-293).

Digits lengthened, narrowed, taking up >1/3 of total cheliceral length. Movable digit length

99 (75-113), fixed digit length 98 (71-113). Fixed digit with a series of small rounded

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. tooth-like projections on the distal half of the digit. Antiaxial face with dorsal setads and

lyrifissure i a , positioned as in previous instars. Lyrifissureid ventro-lateral below

lyrifissure i a . Pilus dentilis on basal one-third of fixed digit, projecting anteriorly.

Interdigital membranes poorly defined, composed of several layers. Longest and most

narrow of membranes, fimbriate and extending beyond tips of digits. Shortest membrane

extending to midpoint of digits. Movable digit with three large distal teeth. Small

crenulations extend from the teeth, posteriorly to the base. Comblike process lengthened

relative to previous instars, forming rows of membranous spines extending from the

proximal edge of teeth to the basal third of the digit. Ventral cheliceral envelope inserted on

distal 1/3 of movable digit. The two portions of the sheath are membranous, one smooth

and leaflike, the other distaily serrate.

Male (Fig. 2.IE). Segments as in previous instars. Cheliceral length (basal segment and

fixed digit, excluding spermatodactyl) 213 (197-222). Fixed digit (excluding the

spermatodactyl) broader and shorter than that of the female. Movable digit 107 (102-113).

Antiaxial face of fixed digit with dorsal setads. Lyrifissure ia and pilus dentilis not

observed. Fixed digit with spermatodactyl. Spermatodactyl 240 (235-254) with smooth

external surface except near the end where twisting is visible. Two internal helical canals

visible at base of each spermatodactyl. Transition between fixed digit and spermatodactyl

smooth. Four interdigitai membranes. Two longest unequal in length, but both densely

covered in minute spines, projecting beyond distal end of the movable digit. Third and

fourth one-half as long and wider. Fourth with spines on rim, but the extent of coverage of

these spines is unclear. Movable digit with two low rounded teeth at the distal end.

Ventral cheliceral envelopes inserted at the base of the movable digits. Comblike process

as in the female, extending from the base of the teeth to the basal one-third of the movable

digit. Other aspects of movable digit as in the female.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2 .5.2 Pedipalps

Larva (0-4-5-4/6) (Fig. 2.2A, B). Leg-like. Length 210 (194-224), approximately 8x

width for entire length. With four recognizable segments: trochanter, femur, genu, and

tibiotarsus. Lengths of segments: trochanter 37 (28-41), femur 78 (75-81), genu 52 (47-

56), tibiotarsus 43 ( 34-51). Trochanters lacking setation. Femora each with four setae

(al, ad], pd2, pi): seta al brush-like, adl spine-like, pd2 and pi pectinate. Setapi ventral

in position. Single lyrifissure dorsally at distal end of femur. Genua each with 5 setae

(a//, adl, ad2, pdl, p ll): setae all and adl pectinate, setae ad2, pdl, and pll spine-like.

Tibial region of each tibiotarsus with four setae: three spine-like and one short spine.

Rudimentary 2-tined palpal claw present (Fig. 2.D: rc). Tarsal region of each tibiotarsus

with 6 setae: two short spines, 2 medium spine-like setae, and two distally located bilobed

setae (bs), “cactus-like” in appearance, reminiscent of solenidia.

Protonymph (1-6-5-4/7) (Fig. 2.2C, D). Shape as in larva. Entire length 282 (273-

288). Lengths of segments: trochanter 55 (51-56), femur 104 (94-113), genu 71 (66-75),

tibiotarsus 52 (47-56). Trochanters each with long pectinate seta vl. Rudimentary

membranous structure (rm) present in position corresponding to insertion of seta v2 in

deutonymph. Femora each with 6 setae. Additional setae adl, an acceleration, and de

novo setae pdl barbed. Setae al longer and bushier than in larva. Lyrifissure same as in

larva. Genua and tibial region of tibiotarsus as in larva. Tarsal region of tibiotarsus with

an additional short ventral spine. Palpal claw as in larva.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Deutonymph (2-6-6-6Z7) (Fig. 2.2E, F). Shape as in previous instars. Entire length

351 (329-376) approximately 7x width. Lengths of segments: trochanter 72 (66-88),

femur 136 (128-150), genu 79 (66-88), tibiotarsus 63 (56-71).

Trochanters each with additional seta v2. Membranous structures associated with v2 setae

rudimentary. Lyrifissures as in protonymph. Femoral setaal extremely bushy, other setae

as in protonymph. Short, pectinate setaal2 added on genu. Tibial region of tibiotarsi with

two additional spine-like, dorsal setae. Tarsal region of tibiotarsi as in protonymph. Palpal

claw as in previous instars.

Female (2-6-6-14-9) (Fig. 2.3A, B). Telescoping shape. Entire length 241 (228-256).

Five recognizable segments. Lengths of segments: trochanter 56 (53-56), femur 77 (71-

85), genu 38 (34-41), tibia 38 (28-47), tarsus 30 (28-34). Trochanteral seta v2 atop

prominent spur, associated with membranous structure (rm) that is much larger than in

immatures. Lyrifissures not visible. Femoral setal pattern as in deutonymph, but setal

shape different. Setae adl, adl, pdl, pd2, and pi stout, almost spine-like, lightly barbed.

Seta adl largest. Setae all more slender, barbed. Distal dorsal lyrifissure not visible.

Genual setae, number and shape, as in deutonymph. Tibiae each with 8 added setae,

yielding a complement of 14. Tarsi each with 9 setae, an addition of 2. Bilobed or

“cactus-like” setae absent. Palpal claws two-tined, of normal appearance and relative size

for Mesostigmata.

Male (2-6-6-14-9) (Fig. 2.3C) Shape as in female. Entire length 232 (224-244).

Lengths of segments: trochanter 56 (51-66), femur 71 (66-75), genu 38 (38-41), tibia 37

(32-41), tarsus 28 (26-32). Seta v2 positioned on a spur but spur much smaller than in

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. female, and lacking associated membranous structures. Trochanteral setae more stout and

bushy than in female. Remaining palpal setation as in female.

2.5.3 Subcapitulum

Larva (Fig. 2.4A). Deutostemal groove shallow, with 5 indistinct rows of 2 denticles

each. Prominent serrate comiculi (co) inserted dorsally (15). Internal malae (im) fimbriate.

Labrum (Fig. 2.4C: la) barely extends beyond internal malae in ventral view. Hypostome

distinctly raised from remainder of subcapitulum, forming a plateau (Fig. 2.4B: hp).

Hypostome bears two pairs of lightly barbed setae, hyp Iand hyp2, arranged in a

transverse row. Rows of 5 to 10 short spines (sp) grouped on prominences at level of

second row of denticles. A few additional short spines scattered about subcapitulum or

arranged in diffuse diagonal lines (Fig. 2.4C: cpt).

Protonymph (Fig. 2.4B). Deutostemal groove as in larva. Comiculi positioned lateral

(20). Internal malae fimbriate. Labrum longer than in larva, distinctly projecting beyond

internal malae. Serrate capitular setae cs added mid-level on subcapitulum, flanking

deutostemal groove. Setae hyp3 added posterior to, and midway between setae hyp Iand

hyp2, resulting in an inverted triangle arrangement. All hypostomal setae situated on raised

prominences. Row of spines at level of second row of denticles less pronounced than in

larva. A few short spines scattered in diffuse rows on remainder of subcapitulum.

Deutonymph (Fig. 2.4C). Deutostemal groove with 6 indistinct rows of 2 denticles each.

Comiculi ventro-lateral (40). Internal malae fimbriate. Labrum as in protonymph. Entire

hypostomal region raised relative to the remainder of subcapitulum. Arrangement of

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. hypostomal setae as in protonymph. Lateral with three pairs of diagonal rows of short

spines. Posterior row as in larva and protonymph (sp), two anterior diagonal rows not on

prominences.

Female (Fig. 2.4D). Distinct deutostemal groove but denticles not visible. Comiculi

modified into flat, lobed, membranous structures (co). Salivary styli (ss) present, very

short, located in pits on a prominence, ventro-median to comiculi. Internal malae

membranous, flowing, surrounding labrum and modified to form a “plow-like” structure

(Fig. 2.4E, Fig. 2.14: im). Paralaciniae (pi) present, positioned between comiculi and

internal malae. Labrum (la) centrally located, densely fimbriate, projects beyond distal end

of other structures. All hypostomal setae smooth, capitular setae cs barbed. Setae hypl

hidden beneath modified internal malae. Setae hypl and hyp2 no longer in a transverse

row, instead hypostomal setae hyp], hyp2, and hyp3 and capitular seta cs almost in a

longitudinal row. Setae hyp3 adjacent to circular structures resembling scoops (sc),

flanking and partly overlapping the deutostemal groove. Sclerotized cuticular points

arranged in three pairs of indistinct diagonal rows, flanking deutostemum. Rows of

spines on prominences (Fig. 2.4C: sp), present in previous instars, absent.

Male (Fig. 2.4E). Sexual dimorphism distinct. Deutostemal groove similar to female but

with 4 indistinct rows of 2 denticles each. Labrum does not extend beyond tips of internal

malae. Scoops on the subcapitular surface not distinct, but indistinct subsurface structures

present. Comiculi, hypostomal setal shape, and setal arrangement as in female.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.5.4 Tritostemum

All instars (Fig. 2.5). Elongate conical base. Length distinctly exceeding width. Base

divides distally into two branches with denticulate collars from which pilose laciniae

project. Tritostemal lengths (including laciniae): larva 79 (75-83), protonymph 101 (88-

107), deutonymph 141 (132-150), female 150 (141-156), male 142 (135-156). Male

tritostemum located behind flaplike genital opening, at gnathosomal insertion. In adults,

tritostemum is flanked by a narrow denticulate fringe of cuticle (Fig. 2.8C: dc).

2.5.5 Gnathotectal process

Larva (Fig. 2.6A). Shape broadly rectangular. Anterior edge spinose along its entire

length. Longest spines lateral. Poorly defined central fold (fd) present.

Protonymph (Fig. 2.6B). Shape similar to larva. Rows of spines more diffuse. Central

fold (fd) distinct.

Deutonymph (Fig. 2.6C). Shape as in previous instars. Central fold visible, one-half

appears to form a pocket for the other.

Female (Fig. 2.6D). Smooth edged, tongue-like shape. Interior portion thicker than the

membranous edge. With centrally located external ridges (rg). Membranous portion with

smooth, anterior edge.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Male (Fig. 2.6E). Roughly triangular in shape. Spinose ridges, overlapping along

midline, approaching a central keel in appearance. Tip of triangle with three strong spines

formed from overlapping layers.

2.5.6 Idiosoma

Larva (Figs. 2.7A, 2.9A). Round in appearance. Weakly sclerotized. Shields not

discernible. Length 233 (154-320); width 234 (188-310).

Dorsum (Fig. 2.9A). With 7 pairs of setae:j3, j5, z5, j6, Z3, Z4, Z5, S4. Podosoma large

relative to opisthosoma: setaej5 slightly anterior of idiosomal midpoint. Setaej5 very

long 310 (282-332) curling posteriorly over dorsum, often interlocking with setae S4.

Setae S4 inserted ventro-lateral, very long 266 (231-294) curling anteriorly over the

dorsum. Remaining dorsal setae very short Eight pairs of glands and lyrifissures.

Venter (Fig. 2.7A). Five pairs of setae: sternal setaestl, st2, st3 all same length (30);setae

Jvl short, spinelike; paranal setaepa 111 (78-130) anterior to anus. Unpaired postanal

seta po 138 (122-164). Large glands (gv31) lateral to anus, near setae S4 Cribrum poorly

developed.

Protonymph (Figs. 2.7B, 2.9B). Shape and sclerotization as larva. Length 393 (348-

568); width 358 (299-524) (N=l 1)

Dorsum (Fig. 2.9B). Hexagonal sculpturing pattern visible, but sclerotization weak.

Podosoma adding setae z2, z4, z6, s4, and s6. Setae j3 and zJ transformed from very

small in larva to long, only setae j6 and z6 very short. Setae j5 very long 365 (314-433).

Opisthosoma adding setae J4, J5, Z2, S2, S3, S5, and R4. Setae J4, Z2, Z3, and S2 very

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. short, setae 75 and R4 short, all other setae long. Setae Z5, S4, and 55 inserted ventro

lateral. Ten pairs of glands and lyrifissures, including addition of lyrifissure idjl.

Venter (Fig. 2.7B) Seven pairs of ventral setae, with addition of setaest5 and 7v2.

Sternal setae approximately equal in length. Setaepa migrated to a position posterior to

anus, forming a transverse row with seta po. AH ventral setae weakly barbed.

Glands stp2 added near setae st2 , and lyrifissures iv5 added between setae stS and coxae

IV. Glands stpl missing. Cribrum clearly defined. Glands gv3 now located on outside

edges of cribrum. Peritremes short, lateral to coxae IV.

Deutonymph (Figs. 2.7C, 2.9C). Shape as in larva, Length 665 (561-785); width 615

(523-710).

Dorsum (Fig. 2.9C). (N= 5) Shields indistinct to absent, some hexagonal sculpturing

visible. Thirteen pairs of podonotal setae with addition of very small setaej4 and s2, and

two pairs of undesignated setae between, respectively,J5 and z5 and j6 and z6. Setae j5

very long 436 (425-454) curling posteriorly over dorsum. Opisthosoma with 15 pairs of

setae with addition of setae 72,75, and SI. Setae JI-4, and setae ZI very short, all other

setae medium to long, and curly. Setae 25,55-55, and R4 inserted ventro-lateral. Total of

12 pairs of glands and lyrifissures associated with dorsal setae. In observations of live

specimens, older deutonymphs develop a mid-dorsal depression.

Venter (Fig. 2.7C). Sclerotization increased from protonymph. Eleven pairs of ventral

setae with addition of setae st4, Jv5, Zv2, and Zv5. Position setae pa as in protonymph.

Sternal setae of similar length. All ventral setae weakly barbed. Glands stp3 added near

setae st3. One pair of lyrifissures and 2 pairs of glands around peritrematal stigmata.

Peritremes short. Lyrifissures ivp added, flanking seta po.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Female (Figs. 2.8B, C, 2.10B, C). Teneral female length 975 (905-1047), width 723

(673-767); mature female length 1365 & 1365, width 1159 & 1234.

Dorsum (Fig. 2.10B, C). Holodorsal shield, hypertrichous with minute spinelike setae.

Entire dorsum finely punctate with many small pores. Sigilla patterns consist of eleven

patches. Two most posterior patches of muscle scars, correspond to dorso-ventral

musculature associated with ventral suckers (sm). Mature female (Fig. 2.10C) with strong

increase in overall size, but similar size shield. Soft cuticle around shield partially

sclerotized. Venter (Fig. 2.8B, C). Highly sclerotized. Endopodal plates for coxae II-IV, metapodals,

exopodals, and peritrematals coalesced into a single shield. Exterior endopodal areas with

corrugated-like structures opposite coxae Il-m (Fig. 2.8A: els). Stemo-genito-ventral

shield incompletely fused to anal shield. Ventral suckers incorporated into stemo-genito-

ventral shield. Hexagonal sculpturing visible from the base of the anal shield continuing

anteriorly, fading towards the center of the stemo-genito-ventral shield. All ventral shields

with very fine punctations and randomly spaced larger pores. Narrow postanal shield (ps)

free, forming posterior rim of opisthogaster.

Eleven pairs of distinct setae (as in deutonymph) situated on ventral shields. Setaestl on

prestemal shield. Setae st2 free on cuticle, but secondary sclerotization in mature females

surrounds the bases of setae st2. Setae st5 inserted posterior to coxae IV. SetaeZv2, Zv3,

and Jv5 on the edge of stemo-genito-ventral shield, external to the ventral suckers. Setae

Jvl and Jv2, between ventral suckers. Setae Jv2 may be inserted either on the stemo-

genital-ventral shield or on small platelets on otherwise unsclerotized cuticle between the

stemo-genito-ventral and the anal shield. Variable numbers of minute and undesignatable

setae (23-40) located on the posterior margin of the postanal shield. A few of these setae

(s) more anteriorly situated. Glands gv3, sternal lyrifissures, and lyrifissures ivp as in

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. deutonymph. Peritrematal shields with two pairs of lyrifissures ipl( , ip2) and three pairs

of glands: gpl, positioned on anterior one-third of peritrematal shield (often indistinct in

mature female due to close proximity of peritreme),gp2, just anterior to the stigma, and

gp3, posterior to the stigma. Homology of these structures with glands and lyrifissures in

the immatures unclear. One pair of lyrifissures anterior (ivo2), another external (ivo3) to

the ventral suckers. Cribrum distinct, posterior to setae po and pa.

Sclerotized solenostomes extending inward from the secondary genital opening at the

internal anterior edge of the ventral suckers, directed anterior and towards the midline

(diagnostic for the genus Narceoheterozercon). Anterior edge of stemo-genito-ventral

shield membranous. Reproductive structure (rs) resembling lyrate organ, positioned

anterior to stemo-genito-ventral shield, then projecting posterior and internal to the

membranous portion of the shield. Distinct sclerotized tube posterior to reproductive

structure under the stemo-genito-ventral shield. Newly molted females differ significantly

in size from mature, egg-bearing females. In mature females, secondary sclerotization

develops in previously membranous areas around the shields (Fig. 2.IOC).

Male (Figs. 2.8A, 2.1 OA). Overall shape as in teneral female. Length 845 (767-916);

width 651 (613- 692).

Dorsum (Fig. 2.10A). Similar to teneral female. Central podonotal patches of sigilla more

prominent than in female.

Venter (Fig. 2.8A). Shields, setation, lyrifissure and gland patterns as in female, but

pores on shields generally larger than in female. Genital shield anterior, covering part of

the prestemal shield and hiding the base of the tritostemum.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.5.7 Legs

Larva (Fig. 2.1 IA, B, C). Leg I antenniform, longest of the three. Leg 1= 578 (531-

598); 11= 399 (337-404); ID= 381 (367-426). Basifemur not distinct. Appearance of distal

end of tarsus I suggestive of pretarsal remnant (Fig. 2.11 A), but distinct ambulacrum or

claws absent. Acrotarsus present. Pretarsal ambulacra and claws present on legs II and

m , but ambulacra Il-m poorly developed.

Setation. Coxae I-III: 2-1-1. Trochanter I = 1-0/0-0/2-1 (4), U = 1-1/0-0/2-1 (5), ffl = 1-

1/0-0/2-0 (4). Femur I = 2-2/1-2/1-1 (9), II = 1-2/1-2/0-1 (7), IB = 1-2/1-1/0-0 (5).

Femur I lacking seta pl2. Genu I = 1-2/1-2/1-1 (8), II = 1-2/0-2/0-1 (6), ffl = 1-2/0-2/0-1

(6). Tibia I = 1-1/1-2/1-1 (7), II = l-t/1-2/1-1 (7), ffl = 1-1/1-2/1-1 (7). Tarsus I with 31

setae (Fig. 2.13A); sensillar field lacks definition. Tarsi D-ffl: 3-3/2-3/2-3(16).

Lyrifissures: total of 5 on all legs; 1 each dorso-distal on trochanter, femur, genu, and tibia;

and 1 on tarsus at basitarsus/telotarsus division,. Two punctate areas (Fig. 2.13A: pa)

present on dorsal side of tarsus I, arranged in a line extending distally from tibial

lyrifissure. Exocrine glands (sensu Fain, 1966) (Fig. 2.7A: eg) in a circular bouquet,

ventro-proximally located on coxa I and occasionally visible at ventro-anterior edge of

trochanter I. Their infundibula point inward to a central point. Their function is unknown.

Large coxal-associated gland (cag) along base of coxa I, posterior to exocrine glands.

Protonymph (Fig. 2.1 ID, leg IV). Leg I antenniform, longest of four. Leg 1= 770 (756-

793), B= 509 (460-531), ffl= 524 (497-546) (N=9), IV= 571 (531-598) (N=8).

Basifemur on legs I-II distinct. Pretarsus on legs I absent. Distal end of tarsus more blunt

than in the larva. Acrotarsus present. Pretarsal ambulacra on legs II -IV present; shape as

in larva.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Setation. Coxae 2-2-2-1. Trochanters 1-ID as in larva; trochanter IV = 1-1/1-0/1-0 (4).

Femur I = 2- 2/1-2/1-1 (9), H = 1-2/1-2/0-1 (7), ID = 1-2/1-1/0-0 (5), IV = 1-2/0-1/0-0

(4). Genu I = 0-2/1-2/1-2 (8), U = 1-2/0-2/0-1 (6), ffl = 1-2/0-2/0-1 (6), IV = 1-2/0-2/0-1

(6). Tibia I = 1-2/1-2/1-1 (8), H = 1-1/1-2/1-1 (7), ID = 1-1/1-2/1-1 (7), IV = 1-1/1-2/1-1

(7). Tarsus I with 35 setae. Sensillar field, lyrifissures, and punctate areas as in larva.

Tarsi II-IV with 17 setae, adding seta dm.

Lyrifissures on legs I as in larva, legs II-IV each with 8 lyrifissures. Each tarsus 2

lyrifissures (1 dorsal at basitarsus / telotarsus division, one ventral lyrifissure added at the

tarsus/telotarsus division). Punctate areas vague for each tarsus and tibiae I-II. Exocrine

glands on coxae I and large coxal-associated glands along base of coxae I as in larva.

Deutonymph. Leg I antenniform and longest of four. Leg 1= 1005 (965-1026), 11= 682

(636-759), 111= 690 (658-737), IV= 683 (430-755). Basifemur on legs I-IV distinct.

Legs I without pretarsal structures. Distal end of tarsus more blunt than previous instars.

Acrotarsus present. Claws and ambulacra present on legs II-IV; ambulacral shape as in

previous instars.

Setation. Coxae as in protonymph. Trochanter I = 0-2/l-l -2 (6), II = 0-0/1-1/2-1 (5), III

= 1-0/1-0/2-1 (5), IV = 1-0/1-0/2-1 (5). Femur I = 1-3/3-1/0-2 (10), U = 2-3/1-2/1-1 (10),

ffl = 1-2/1-2/1-0 (7), IV = 1-2/1-2/1-0 (7). Genu I = 2-2/1-2/1-2 (10), II = 2-2/1-2/1-1

(9), HI = 2-2/1-3/1-1 (10), IV = 2-2/1-3/1-1 (10). Tibia I = 2-2/1-2/1-2 (10), D = 2-2/1-

1/1-1 (8), ffl = 1-2/1-2/1-1 (8), IV = 1-2/1-2/1-1 (8). Tarsus I with 43 setae; sensillar

region more defined than in previous instars but not as discrete as in adults. Two large

setae on proximal portion of each tarsus: ventral one stout and the other anterio-lateral very

strongly spinose. Tarsi II-IV each with 18 setae, with addition ofmv.

Tarsus I with two lyrifissures: one added dorsally near tibial lyrifissure and ventral

basitarsus/telotarsus division as in protonymph. Other lyrifissures as in protonymph.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Punctate areas on tarsus I similar to protonymph but more prominent than in previous

instars; located in lightly sclerotized oval depressions. Coxa I with 2-4 exocrine glands

anterio-basal and trochanter I with 1 or 2 clusters on anterior edge Additional gland (Fig.

2.7A: ag) added posteriorly along bases of coxae I, for a total of three glands along the

base of each coxae I. Trochanteral structures (Fig. 2.12B, E: ts), dorsally located on each

trochanter I and occasionally on trochanter II. Sculpturing of legs light.

Adults (Fig. 2.12A, B, C, D) Leg I antenniform and longest of four. Female (N= 5; 2

mature, 3 teneral): Leg 1= 1066 (1017-1096); leg U= 747 (658-785); leg 01= 769 (748-

1096); leg IV= 814 (793-834). Males (N= 5): Leg 1= 1103 (1029-1159); leg 0= 758 (711-

785); leg 10= 768 (748-793); leg IV= 820 (785-849). Some sexual dimorphism; legs I in

males slightly longer than in females, and males with an extra ventral seta pv2)( on femur

0. Basifemur on legs I-IV distinct. Legs I with discrete pretarsal ambulacra and claws.

Acrotarsus present. Ambulacra of legs fl-IV larger than in immatures.

Setation. Coxae and trochanters as in deutonymph. Femur I = 1-3/2-2/1-1 (10), 0 = male

2-3/1-2/2-1 (11), female 2-3/1-2/1-1 (10), ffl = 1-2/1-2/1-0 (7), IV = 1-2/1-2/1-0 (7).

Genu 1 = 2 2/1-2/1-2(10), 0 = 2-2/1-2/1-1 (9), 01 = 2-2/1-3/1-1 (10), IV = 2-2/1-3/1-1

(10). Tibia I = 2-2/1-2/1-2 (10), D = 2-1/1-2/1-1 (8), 01 = 2-1/1-2/1-1 (8), IV = 1-2/1-

2/1-1 (8). Tarsus I (Fig. 2.13 B, C) with 43 setae (as in the deutonymph). Setal

arrangement different from immatures: 22 sensilla in a discreet, inverted triangle-shaped

sensillar field, slightly depressed relative to surrounding cuticle. Edges of triangular field

with outside setae raised. A distinct pennant-shaped seta (pe) on edge of sensillar field.

Tarsi fl-IV each with 18 setae, as in deutonymph

Lyrifissures as in deutonymph. Glands on coxae as in deutonymph (Fig. 2.12A). Legs I

exocrine glands now also observed at anterior edge of each trochanter. Dorsal trochanteral

structures, variable in appearance: frequency of presence: leg 1= 5/10, leg 0= 8/10, leg 10=

10/10, leg IV= 9/10. Structures appear variable from distinct form (ts) to more diffuse

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. form appearing as a slit or series of cracks running from the distal end of the dorsal side of

the trochanters toward the coxae (Fig. 2.12B). Sculpturing visible on legs. Ventral ridges

(cr) on coxae II-IV and trochanters I-m (N=10). They were present in all specimens on

coxae of legs II and III and only vaguely visible on leg IV. Trochanters exhibited these structures with less consistently: trochanter 1= 1/10, n= 7/10 and m= 6/10, trochanter IV not visible.

2.6 DISCUSSION

This first description of the immatures of Heterozerconidae has revealed some

interesting developmental patterns. InNarceoheterozercon , the immatures are

hypotrichous and free-living, while the adults exhibit hypertrichy and are found on

millipedes. The pattern of hypotrichy in the immatures followed by hypertrichy in the

adults is shared by other mites such as Trombiculidae. The combination of hypotrichous

predatory immatures however is not. This is a reversal of the tendencies exhibited by most

ectoparasitic mites (Radovsky, 1969). In the immatures, setae j5 and S4 often interlock

their curling ends. Long idiosomal setae are common in many families of mites but the

tendency to intertwine may be unique to Narceoheterozercon.

The regressive tendencies generally exhibited by the immatures are not apparent in

the legs. The leg chaetotaxy of the larva is remarkably similar to larvae of both free-living

Gamasina and Trigynaspida when compared to Kethley’s (1974) table of the same.

Notably, the differences all involve missing setae, including seta pl2 on femur I, a loss

shared with Euzercon latus (Banks 1909) and Choriarchus reginus Kinn 1966; seta d3 on

femur m , shared with Celaenopsidae, and seta d4 on tibia I, shared with Choriarchus

reginus.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The immature tarsus I lacks an ambulacrum and claws, while legs II-IV appear

normal. A similar situation exists in the Sejina, Microgyniina, and Trigynaspida. Unlike

those taxa, adult heterozerconids possess normal pretarsi on legs I-IV. The well delineated

triangular shaped sensillar field of the adult tarsus I is not distinct in the larva and

protonymph. In the deutonymph however, it has become more defined and is vaguely

recognizable as a sensillar field.

The overall reductive trends within the Heterozerconina, relative to the “normal”

gamasine pattern are also found in the leg setae of the adults (Evans, 1963).

Narceoheterozercon exhibits reductive setal trends in comparison with other members of

its own family. Narceoheterozercon lacks the heavy femoral spines associated with

Asioheterozercon Fain, 1989 and Amheterozercon Fain, 1989 (Fain, 1989). Within the

infraorder Heterozerconina, both Heterozerconidae and Discozerconidae show an unusual

tibial chaetotactic pattern: I (10), II (8), III (8), IV (8); where the normal gamasine tibial

pattern is: I (14), II (10), III (8) and IV (10). Presence of an acrotarsus in tarsus I for all

instars is a trait of early derivative Mesostigmata (Lindquist, 1984). A vestige of the

acrotarsus is sometimes visible on tarsus I in the Opilioacarida (Lindquist, 1984).

In the pedipalps, paedomorphic tendencies are mixed with accelerated traits. The

pedipalps of the immatures exhibit extreme reductive tendencies. Even the palptarsal claw

is reduced, which so far, is unique to the Heterozerconidae. Only the palptrochanter and

palpgenu follow the normal gamasid trends for developmental chaetotaxy (Evans, 1963b).

In accordance with the juvenile appearance, are numerous setal reductions. These are

obvious in the immature palptibia which adds only 2 setae to the larval complement. The

final molt is accompanied by an addition of 8 palptibial setae, instantaneously reaching the

normal adult gamasid complement of 14 (Evans, 1963b). The palptarsus maintains a

juvenile appearance with an addition of only three setae over the entire ontogeny, totaling

nine setae in the adult. This is far short of the IS setae expected for an adult gamasid

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. palptarsus (Evans, 1963b). The peculiar “cactus-like” setae are reminiscent of solenidia in

appearance. The appearance of solenidia on the palp is found in Acariformes,

Opilioacarida, Holothyrida, and Ricinulei (Lindquist, 1984).

Accelerated additions and the presence of supernumerary palpal setae are relatively

rare in the Mesostigmata (Evans 1963b), and all the more surprising in Heterozerconidae

given the generally paedomorphic appearance of the immatures. InNarceoheterozercon

ohioensis, additions and accelerations are confined to the palp femur of the protonymph.

These include the accelerated addition of setae adl and the de novo appearance of setae

pdl, a supernumerary addition thus far believed to be restricted to the higher

Antennophorina (Evans and Till 1965). The only other report of accelerated additions of

palpal setae is for the protonymph ofBlattisocius Keegan, 1944 (Ascidae) with an

accelerated addition of trochanteral seta v2 (Evans, 1963b).

The gnathosoma differs greatly between the free-living predatory immatures and the

adult commensal heterozerconids. The immatures possess the horn-like comiculi common

to most other Mesostigmata. These structures are used in manipulating prey. In contrast,

the comiculi in the adults have become membranous, a characteristic often associated with

myrmecophilous and parasitic species (Hughes, 1959). The gnathosoma also differs

greatly within the Heterozerconidae, depending on feeding methods. In

Narceoheterozercon, both the females and males possess large membranous internal malae

(Figs. 2.4 D, E, 14: im) presumably for feeding on millipede exudates. Millipede

associates Promegistus Trag&rdh 1906 and Neomegistus Tragirdh 1906 reportedly feed in

a similar fashion (Lawrence 1939, Trag&rdh 1907), and also possess modified internal

malae resembling those in Narceoheterozercon. In Zeterohercon amphisbaena

Flechtmann and Johnston 1990, a parasitic heterozerconid associated with a reptile, the

internal malae form a group of setose structures (Flechtmann and Johnston, 1990). The

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. gnathotectal process is sexually dimorphic inNarceoheterozercon ohioensis. The male

possesses a triangular gnathotectum and the female possesses a tongue-like, rounded one.

In Zeterohercon, however, both the male and female show the triangular toothed “male”

form of gnathotectum. It is unclear whether parasitic behavior is responsible for the lack of

sexual dimorphism. In femaleN. ohioensis, teeth are located on both cheliceral digits with

a comblike structure only on the movable digit. In Zeterohercon amphisbaena , there are

no teeth on either digit but both digits possess a comblike structure, heaviest on the fixed

digit.

Reductions continue into the sternal area. Ironically, in Narceoheterozercon which

possess an abundance of unusual, possible gland-like structures (i.e. the corrugated-like

structures, trochanteral structures and punctate areas) glands stpl are missing. Setae st3,

present in the immatures, are missing in the adults. In the female, the genital region of the

stemo-genito-ventral shield is membranous. Due to the number of separate platelets, the

sternal shield takes on a fragmented appearance. A fragmented sternal region is also a

characteristic of Sejina, Microgyniina, and Trigynaspida (Camin, 1955).

2.6.1 Ventral suckers

Heterozerconidae are best known for the strange ventral suckers (Figs. 2.15, 2.16)

found in most adults. Fain (1989) made the only attempt to address the function of these

structures. He focused on their musculature and adhesive qualities. The consensus of all

literature on the Heterozerconidae is that the structures perform an adhesive function.

Observations of heterozerconids from around the world have so far, resulted in only one

group of “suckerless” species from the Choco faunal region of Ecuador. This observation

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. supports the hypothesis that presence of the suckers in Heterozerconidae evolved early in

the history of the family. The Heterozerconidae is an important family of mites and further

investigations will undoubtedly have a substantial impact on the rest of the Acari.

2.7 ACKNOWLEDGMENTS

My thanks to Dr. Dan Potter of the University of Kentucky, who collected the new

genus and kindly provided the original specimens. To my adviser Hans Klompen for his

advice and example. To Dr. Rodger Mitchell, who provided invaluable direction and

patience toward my efforts. To A.W. Cusick, Chief Botanist, Division of Natural Areas

and Preserves, ODNR, whose suggestions were instrumental in field site locality. I am

grateful to the Ohio Department of Natural Resources, Division of Natural Areas and

Preserves, for providing permits (#RP-120, 260) and permission to use Little Rocky

Hollow as my primary study area. I am grateful to the following people for providing

comparative specimens of undescribed genera and species from the United States: Dr.

Gary Mullen of Auburn University (thanks also to Dr. Ron Cave, who provided me with

further details of collecting data from the Alabama specimens); Drs. Petra Sierwald, Dan

Summers, Phil Parillo and Jason Bond of the Field Museum of Natural History, Chicago,

Illinois; Dr. Ron Ochoa of the National Museum of Natural History, Washington, D.C.;

and Dr. Gerry Krantz, Oregon State University. My sincere appreciation to Dr. John

Kethley whose understanding of the Heterozerconidae, provided helpful insights and

direction into the study of this enigmatic family.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 2.8 LIST OF REFERENCES

Alberti, G. 1979. Fine structure and probable function genital papillae and Claparede organs of Actinotrichida. In J. Rodriguez (ed.) Recent Advances in Acarology. Vol. II. New York: Academic Press, pp. 501-507.

Alberti, G. and L. B. Coons. 1999. Chelicerata Arthropoda. Volume 8C. New York, NY: John Wiley & Sons, Inc., pp. 515-1265.

Athias-Henriot, C. 1975. Nouvelles notes sur les Amblyseiini, 2. Le releve organotaxique de la face dorsal adulte (Gamasides protoadeniques, Phytoseiidae). Acarologia, 17: 20-29.

Berlese, A. 1888. Acari Austro-American quos collegit Aloysius Balzan. Bull. Soc. It., 20: 171-222 (pi. XI, fig. 1).

Camin, J.H. and F. E. Gorirossi. 1955. A revision of the suborder Mesostigmata (Acarina), based on new interpretations of comparative morphological data. Chicago Acad. Sci. Spec. Publ., 11: 1-70.

Coineau, Y. and L. van der Hammen. 1979. The postembryonic development of Opilioacarida, with notes on new taxa and on a general model for the evolution. In E. Piffl, (ed.) Proceedings of the 4th International Congress o f Acarology. Budapest: Akademiai Kiado, pp. 437-441.

Evans, G. O. 1963a. Observations on the chaetotaxy of the legs in free-living Gamasina (Acari: Mesostigmata). Bull. Br. Mus. (Nat. Hist.), 10: 275-303.

Evans, G. O. 1963b. Some observations on the chaetotaxy of the pedipalpi in the Mesostigmata (Acari). Ann. Mag. Nat. Hist., 13: 513-527.

Evans, G. O. 1965. The ontogenetic development of the chaetotaxy of the tarsi of legs II- IV in the Antennophorina (Acari: Mesostigmata). Ann. Mag. Nat. Hist., 8: 81-83.

Evans, G. 0 . 1967. Observations on the ontogenetic development of the leg chaetotaxy of the tarsi of legs II-IV in the Mesostigmata (Acari). In G. O. Evans (ed.) Proceedings of the 2nd International Congress o f Acarology. Budapest: Akademiai Kiado, pp. 195-200.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Evans, G. O. and W. M. Till. 1965. Studies on the British Dermanyssidae (Acari: Mesostigmata). Part I. External morphology. Bull. British Mus. Nat. Hist. (Zool.), 12: 247-294.

Fain, A. 1966. Glandes coxales et femorales chez les acariens du groupe des Mesostigmates. Acarologia, 8: 1-8.

Fain, A. 1989. Notes on mites associated with Myriapoda. IV. New taxa in the Heterozerconidae (Acari, Mesostigmata). Bull. Ann. Soc. R. Beige. Entomol., 59: 145-156.

Flechtmann, C. H. W. and D. E. Johnston. 1990. Zeterohercon, a new genus of Heterozerconidae (Acari: Mesos'igmata) and the description ofZ£terohercon amphisbaenae n.sp. from Brasil. Int. J. Acarol., 16: 143-148.

Gerdeman, B.S., Klompen, H. and L. K. Tanigoshi. 2000. Insights into the biology of a mite-millipede association. In Wytwer J. and S. Golovatch (eds.) Progress in Studies on Myriapoda and Onychophora. Fragm. Faun., 43: 223-227.

Griffiths, D. A., W. T. Atyeo, R. A. Norton and C. A. Lynch. 1990. The idiosomal chaetotaxy of astigmatid mites. J. Zool. (Lond.), 220: 1-32.

Hopkin, S.P. and H.J. Read. 1992. The Biology of Millipedes. New York: Oxford University Press, Oxford, 233 pp.

Hughes, T. E. 1959. Mites or the Acari. London: Athlone Press, 225 p.

Keeton, W. T. 1960. A taxonomic study of the millipede family Spirobolidae (Diplopoda: Spirobolida). Mem. Amer. Ent. Soc., 17: 1-146.

Johnston, D. E.and M. L. Moraza, 1991. The idiosomal adenotaxy and poroidotaxy of Zerconidae (Mesostigmata: Zerconina). In F. Dusb&bek, and V. Bukva, (eds.) Modem Acarology: Vol. Prague:2. Academia, pp. 349-356.

Kethley, J.B. 1974. Developmental chaetotaxy of a paedomorphic Celanopsoid, Neotenogynium malkini n. g., n. sp. (Acari: Parasitiformes: Neotenogyniidae, n. fam.) associated with millipedes. Ann. Entomol. Soc. Am., 67: 571-579.

Krantz, G. W. 1978. A Manual of Acarology. Corvallis: Oregon State University Book Stores, 509 pp. 32

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Lawrence, R. F. 1939. Notes on the habits of the two mites living on South African millipeds. Trans. Roy. Soc. S. Africa., 27: 233-239.

Lindquist, E. E. 1984. Current theories on the evolution of major groups of the Acari and on their relationships with other groups of Arachnida, with consequent implications for their classification. In D. A. Griffiths and C.E. Bowman (eds.), Acarology VI, Vol. I. Chichester: Ellis Horwood, pp. 28-62.

Lindquist, E. E. 1994. Some observations on the chaetotaxy of the caudal body region of gamasine mites (Acari: Mesostigmata), with a modified notation for some ventrolateral body setae. Acarologia, 35: 323-326.

Lindquist, E. E. and G. O. Evans. 1965. Taxonomic concepts in the Ascidae, with a modified setal nomenclature for the idiosoma of the Gamasina (Acarina: Mesostigmata). Mem. Ent. Soc. Can., 47: 1-64.

Lindquist, E. E. and M. L. Moraza. 1993. Pyrosejidae, a new family of trigynaspid mites (Acari: Mesostigmata: Cercomegistina) from middle America. Acarologia, 34:283- 307.

Lindquist, E. E. and M. L. Moraza. 1998. Observations on homologies of idiosomal setae in Zerconidae (Acari: Mesostigmata), with modified notation for some posterior body setae. Acarologia, 39: 203-226.

Radovsky, F. J. 1969. Adaptive radiation in the parasitic Mesostigmata. Acarologia, 11: 450-483.

Trag&rdh, I., 1907. Description of two myriopodophilous genera of Antennophorinae, with notes on their development and biology. Ark. Zool. 3: 1-35.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. um ia mm ce n. sp. Chelicerae. A. larva, B. protonymph, C. deutonymph, D. female, id B iim Narceoheterozercon ohioensis ce E. E. male, (ce) ventral cheliceral envelope, comblike(cp) process, (mm) interdigital membranes, dentilis. (pd) pilus Figure 2.1: -u

of the copyright owner. Further reproduction prohibited without permission. Figure 2.2: Narceoheterozercon ohioensis n., gen., n. sp. Immature Pedipalps. A. larva, B. larval palptibiotarsus, C. protonymph, D. protonymph palptibiotarsus, E. deutonymph, F. deutonymph palptibiotarsus. (rc) rudimentary palptarsal claw, (rm) rudimentary membranous structure. 35

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.3: Narceoheterozercon ohioensis n. gen., n. sp. Adult Pedipalps. A. female, B. female palptarsus, C. Male, (rm) rudimentary membranous structure.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.4: Narceoheterozercon ohioensis n. gen., n. sp. Subcapitulum. A. larva, B. protonymph, C. deutonymph, E. female, F. male, (co) comiculi, (cpt) cuticular points, (hp) hypostomal plateau, (im) internal malae, (la) labrum, (pi) paralaciniae, (sp) short spines, (ss) salivary stylus.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.5: Narceoheterozercon ohioensis n. gen., n. sp. Tritostemum. A. larva, B. protonymph, C. deutonymph, D. female, E. male.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.6: Narceoheterozercon ohioensis n. gen., n. sp. Gnathotectal Process. A. larva, B. protonymph, C. deutonymph, D. female, E. male. 39

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.7: Narceoheterozercon ohioensis n. gen., n. sp. Immature Venters. A. larva, B. protonymph, C. deutonymph. (cag) coxal associated gland, (eg) exocrine glands.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission Figure 2.8: Narceoheterozercon ohioensis n. gen., n. sp. Adult Venters. A. male, B. teneral female, C. mature female, (els) corrugated-like structures, (dc) denticulate cuticular fringe, (rs) reproductive structure, (s) variable postanal setae.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.9: Narceoheterozercon ohioensis n. gen., n. sp. Immature Dorsum. A. larva, B. protonymph, C. deutonymph.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. mriOOl / \ / I iiO mriOIM uirioOI

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.10: Narceoheterozercon ohioensis n. gen., n. sp. Adult dorsum. A. male, B. teneral female, C. mature female, (sm) sucker muscle scars.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. • *

V.»V » * r. » o

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.11: Narceoheterozercon ohioensis n. gen., n. sp. Immature legs. A. larva, leg I, B. larva, leg II, C. larva, leg ID, D. protonymph, leg IV.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. uiriooi Reproduced with permission ofthe copyright owner. Further reproduction prohibited without permission. Figure 2.12: Narceoheterozercon ohioensis n. gen., n. sp. Adult Legs. A. male leg I (tarsus absent), B. male leg II, C. male leg HI, D. male leg IV, E. trochanteral structure, (ts) trochanteral structure.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.13: Narceoheterozercon ohioensis n. gen., n. sp. Tarsus I. A. Larva, B. female partial tarsus/acrotarsus. C. male.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 50pm 50pm I 1100pm 1100pm

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2.14: Narceoheterozercon ohioensis n. gen., n. sp. Female Subcapitulum. SEM. 53

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 2. 15: Narceoheterozercon ohioensis n. gen., n. sp. Female ventral sucker.

Figure 2. 16: Narceoheterozercon ohioensis n. gen., n. sp. Female ventral sucker.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 3

Life History of a North American Heterozerconid

Narceoheterozercon ohioensis with

Comparative Data for a Tropical Species.

3.1 INTRODUCTION

Decaying wood provides an array of habitats with moderate temperatures and high

humidity. Some of these are natural cavities, others are tunnels cut by insects that leave

wood particles and feces behind. A diverse biota of fungi, insects, mites and other

arthropods occupy these cavities.

Many social and eusocial orders of insects are common in decaying wood. The

complex communities in these relatively stable habitats are sites for the evolution of

symbioses. It is considered to be the original habitat of Astigmata; mites that possess the

largest number of symbiotic associations in the Acari (OConnor, 1982). Symbiotic

associations are also common among the Mesostigmata. Forty-five mesostigmatid families

contain mite/arthropod associations (Hunter and Rosario, 1988). Forty-two of these

associations are with wood inhabiting species, or species that frequent decaying wood.

Millipedes are some of the largest arthropods inhabiting decaying wood. 55

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Acari are commonly associated with millipedes. Within the order Mesostigmata, 46

species in 9 families are associated with millipedes. The associations range from simple

habitat associations to complex parasitic relationships. Podocinids attracted to the food

resources often hunt in the accumulations of millipede frass, whereas Narceolaelaps

Kethley, 1978 is an obligate parasite ofNarceus Rafinesque (Kethley, 1978). Despite the

numerous associations, mites have rarely evolved strict symbiotic associations with

millipedes. Neotenogyniidae is the only family of mites known to have an exclusive

millipede association.

Heterozerconidae is a rarely collected millipede associate. The adults possess

ventral suckers used in adhesion to their host millipedes. The adults are commensals while

the immatures live off the millipedes in their “nest” areas under bark of decaying logs.

Although primarily associated with millipedes, a few reptile associations occur (Finnegan

1931, Lizaso 1979, Flechtmann and Johnston, 1990). Most of the Heterozerconidae

appear to have an obligate association with millipedes. The family diverged into 13

described genera of millipede associates found throughout the world. The few exceptions

appear to have become secondarily associated with reptiles.

This investigation is the first study of the biological and ecological traits of a

heterozerconid and is centered on the behavior and life cycle of the North American

heterozerconid, Narceoheterozercon ohioensis. (Chapter 2). This mite may represent the

northern range for Heterozerconidae. Because Heterozerconidae is primarily a tropical

family of mites, Narceoheterozercon ohioensis may not exhibit representative behavior

for the family. In order to provide a representative account of the range of life histories

within the Heterozerconidae, a concurrent Held study of a Philippine species was

performed for comparison.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.2 MATERIALS AND METHODS

3.2.1 Temperate Field Site

Little Rocky Hollow lies in the ungiaciated area of southeast Ohio, in a region

known as the “Hocking Hills”. These uplands mark the southern limit of the glaciers and

in this area, stream cutting into the resistant Blackhand sandstone and conglomerate

(Wolfe, et al. 1949) form steep valleys.

The hollow is typical of the area, being characterized by sharp ridges, cliffs,

gorges, grottoes, ledges, and steep slopes sometimes littered with huge blocks broken off

from the cliffs above. Many valleys lead back to waterfalls 12 -30 meters in height.

Although the area was not glaciated, the “Hocking Hills” at the glacial front had low

temperatures and received deposits of glacial outwash. Even today the microclimates of

these sharp cut valleys are cool and moist habitats where relict boreal, hemlock-hardwood

communities and deciduous communities still persist (Wolfe et al., 1949). These hollows

have a mild moist microclimate and the rock outcroppings contribute to a neutral calcium

rich soil.

The mineral resources, abundance of downed logs and the seclusion of the hollow

establish it as a habitat for the millipedes which have high calcium requirements for cuticle

formation and oogenesis (Hopkin and Reed, 1992).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.2.2 Temperate Field and Laboratory Techniques

The hosts, Narceus annularis (Rafinesque) were collected and adult mites were

recovered from the millipedes. Millipedes were found under the bark of rotting logs,

walking on the forest floor and in tree holes. Each millipede was checked for mites. Notes

on sex and location for both the mites and their hosts were recorded. Millipedes with mites

were brought back to the lab.

The collecting regimes were defined: One 3 hour search/month was performed

from November to April. Beginning in April and through July, I increased collecting to

two 3 hour sessions a month. During the main activity period of the mites, August through

October, a three hour collection was done once a week until two consecutive collecting trips

failed to locate millipedes. Keeton’s (1960) morphometric formula was used to determine the millipede

species. Voucher specimens of the millipedes are deposited in the Acarology Laboratory,

The Ohio State University, Columbus, Ohio (OSAL). A few immature mites were

obtained from field collections but most were from laboratory cultures. Laboratory cultures

were maintained at room temperature of 21 °C in plastic containers on a substrate of milled

sphagnum moss.

Specimens for slide mounts were cleared in lactophenol and mounted in Hoyer’s

medium (Krantz, 1978). These slides were studied with phase contrast and differential

interference contrast systems.

The activities of the mites were observed under a dissecting microscope and

significant behaviors of the mites, such as locomotion, mating, documentation of instars

and response by adult mites to millipede defensive chemicals were recorded on S-VHS

videotapes. The videotapes are deposited at the Acarology Laboratory at the Ohio State

University (OSAL). Isolated mites were observed in small (IS ml) rearing cups with a

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. dampened substrate of plaster of Paris and activated charcoal. In order to observe the mites

in situ, the millipedes were placed into test tubes, which limit their movement and stress

from handling.

The mite cultures maintained for 31 months, were observed 1-6 hours weekly.

Observations of 1 - 2 hours each were made at different periods of the day, most often in

the late afternoon.

Heterozerconidae is a relatively rare family of mites primarily associated with

millipedes, a little known host. In Ohio, populations of heterozerconids are low compared

to those in tropical regions, mainly due to a single generation/year, low egg

production/female mite and a limited range for the host millipedes. Less than half the

millipedes in Little Rocky Hollow were infested. Total numbers of mites/collecting trip

were 0-15 for most of the year other than the mating season at the end of August and early

September. Immatures were limited to those produced in laboratory cultures and

immatures successfully produced were few. This resulted in low numbers.

3.2.3 Tropical field site and field and laboratory techniques

The study site is the Forestry campus of University of the Philippines at Los Banos

(UPLB). The campus is located at the foot of Mt. Makiling in Laguna Province on the

main island of Luzon, in the Philippines. The rainy season begins in June and continues

through November with rains decreasing by December. December and January represent

the driest and coolest months.

Ten infested millipedes were collected each month from September 2000 to

September 2001, in order to establish the phenology of a tropical heterozerconid.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Millipedes were taken to the lab, where sex of the host and numbers of mites/millipede

were recorded. Millipedes were collected by checking under the leaves in the forest floor.

Logs when available, were checked for millipedes.

Attempts to culture the immatures were unsuccessful. Possible causes could

include a high laboratory room temperature and ants which invariably infested each

container despite efforts to prevent this from occurring. In the tropics, it was necessary to

field collect the immatures.

Samples of millipede frass were collected each month at the same sites. The

samples were placed in Berlese funnels. The immatures were recovered and their instar

was recorded. In contrast to the Ohio immatures, the tropical heterozerconid immatures

exhibit shield formation and are capable of being recovered by a Berlese funnel,

simplifying collection. Immatures were placed in 95% EtOH.

3.3 RESULTS AND DISCUSSION

3.3.1 Temperate Host Requirements

Narceus annularis is a long-lived and iteroparous detritivore (Hopkin And Read,

1992). However in “Little Rocky Hollow”, Narceus annularis is omnivorous, feeding on

polypores, grazing on algae, aggregated around bird droppings and in one instance of

camivory, a millipede fed on a beetle larva. Generally iteroparous millipede species require

rotting logs for feeding and oviposition (Blower 1969, 1970).

A decaying log provides several different microhabitats. Narceus sp. prefer to be

on the wood under the bark (O’Neill, 1968). They also exploit certain downed logs

without bark, such as Canadian hemlock. The sapwood of this tree develops a light

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. shredded texture under a paper-thin outer shell. The decay process produces an enclosed

space. Millipedes prefer the moister spaces in which the superficial wood layers are

fibrous (O’Neill 1968).

Millipedes often tend to aggregate (Crawford et al., 1987) and benzoquinone

secreted by the defense glands in Narceus may act as an aggregation pheromone (Crawford

et al., 1987). Aggregations of millipedes may occur in spaces large enough for the females

to oviposit and with resources to support the development of the immature millipedes and

mites (Baneijee, 1967). Millipede eggs and immatures were most numerous in large

cavities in the logs, with extensive accumulations of millipede frass which moderate the

high humidities needed for oviposition. High humidity serves to prevent desiccation of

millipede eggs (Baneijee, 1967) and the thin cuticles of the first three millipede instars

(Crawford et al., 1979). Narceus annularis was also observed to molt in protective

spaces, beneath the loose bark of downed logs, sometimes forming a molting chamber

from chewed wood fibers. Neither a preference for a particular tree species, nor a size

preference was noted (Table 3.1).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Beech Fagus grandifolia

Black cherry Prunus serotina

Canadian hemlock Tsuga canadensis

Oak Quercus sp

Pine Pinus sp

Sycamore Platanus occidentalis

Table 3.1 Identifiable species of logs inhabited by Narceus annularis.

Millipedes were collected in logs ranging from as small as 7.5 cm in diameter

(pine), to a 58 cm diameter oak. The stage of decay appears to be a major factor attracting

millipedes. Decayed beeches (Fagus grandifolia) often provide expansive protected spaces

under sheets of loose bark.

External influences determine how a log decays. The location of a downed log,

weather and humidity levels as well as the direction of fall relative to surrounding

topography, can all affect the decay process. Trees, located on steep slopes, may be easily

uprooted during storms. Canadian hemlock possess shallow root systems. Many of them

grow on steep slopes and are often uprooted during storms. Localities with large numbers

of these downed trees may support large populations of millipedes.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.3.2 Vegetation

Three transects were taken at Little Rocky Hollow. The transects access light,

slope, and humidity in the various regions of the study area. The West-facing transect

leads from the ridge to the floodplain. The “Floodplain transect” extends along the lowest

part of the hollow. The “East-facing transect” covers the, east-facing slope on the opposite

ridge and continues down to the flood plain. The following protocol was used for transect data collection: the transect was

defined and at 20 pace intervals, trees within reach of a meter stick were recorded. The trail

was so narrow that there were no visible edge effects.

Little Rocky Hollow is primarily a beech, hemlock, maple forest. The area is not

particularly diverse, primarily dominated by 8 species of trees. Changes in vegetation

occurring along each transect are due to differences in light and moisture.

163 TREES

Beech Fagus grandifolis 27%

Red maple Acer rubrum 18%

Canadian hemlock Tsuga canadensis 13%

Virginia pine Pinus virginiana 13%

Other 29%

Table 3.2: “West-facing transect”. Four most prominent tree species.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 84 TREES

Elmsp. Ulmus sp. 21%

Witch-hazel Hammamelis virginiana 20%

Canadian hemlock Tsuga canadensis 17%

Tulip tree Liriodendron tulipifera 12%

Other 30%

Table 3.3: “Floodplain transect”. Four most prominent tree species.

117 TREES

Canadian hemlock Tsuga canadensis 50%

Tulip tree Liriodendron tulipifera9%

White oak Quercus alba 9%

Virginia pine Pinus virginiana 6%

Other 26%

Table 3.4: “East-facing transect”. Four most prominent tree species.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Pine, indicative of dry conditions was often found near the ridges of both the east

and west facing transects. Middle slopes with a mixture of conditions, possess the most

variety. Canadian hemlock prefers lower levels of light and dominates the lower slopes

and is the only tree species in the top 4 species in all 3 transect areas.

The most gradual west facing slope receives the most sun and has the highest

number of tree species, 22. The upper and middle slope areas of this transect included the

most variety with maple, sassafras and oak. Beeches are shade tolerant and found at the

lower portion of the slope.

The east facing slope is the steepest with a narrow ridge, hence it receives fewer

hours of direct sun. This may partly account for the low diversity, only 13 tree species.

An oak, tulip tree mix grow on the middle of the slope.

The “Floodplain’' transect has 14 species. The sandy soil, lowest light levels in the

hollow and periodic flooding, create stringent limiting conditions. The floodplain consisted

of a mixture of the tree species rather than sections with dominant trees. Witch-hazel

(Hammamelis virginiana) which prefers periodic flooding, was one of the four

predominant species in that transect.

Narceus were found in all transect areas, but were most often collected on the

slopes near the hollow bottom. Narceus americanus (Beauvois) prefers the sides of

slopes (O’Neill, 1968). A similar preference occurs in Narceus annularis in Little Rocky

Hollow. Slopes allow millipedes to select suitable micro-habitats. During periods of

heavy rainfall, millipedes move up from wet areas to moderate conditions. In periods of

drought, they move down to logs that are moist (O’Neill, 1968). Movements of the

millipedes in response to moisture can separate the mites from the millipedes. Years with

extended wet or dry conditions can result in accidental host associations.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. In the fall of 2000, newly molted heterozerconids were found on unusual hosts; a

camel cricket, (Rhaphidophorinae) and a beetle, Megalodacne heros Say (Erotylidae).

Reductions in population can potentially result from these asynchronous episodes.

3.3.3 Phenology

Heterozerconids are long-lived mites with an average life cycle of females at least

one year. The mites are obligate temporary associates sharing a commensal relationship

with their host millipedes. Neither the adult nor immature millipedes appear to be disturbed

or derive any benefit from the presence of the mites. In contrast the millipedes are

necessary for the survival of the mites. The life cycle of the mites is timed with that of their

host.

Narceus and Narceoheterozercon Timeline:

April------May— June------July------Aug— Sept------Oct—Nov

Millipedes emerge eggs immatures molt emerge mate disperse overwinter

Mites on millipedes eggs Lv Pn Dn adults mate overwinter

The activity of millipedes begins in April (Fig. 3.1), following the onset of

sustained warm temperatures, usually in late April or May. At this time, the female

heterozerconids outnumber the males. Mature females are large: their average width 1159

|im is about 50% larger than teneral females. Mature females develop a deep brown color

with a conspicuous dorsal dome as a result of egg development (Chapter 2). The largest

number of eggs seen in a female at any one time was 6 and because only single eggs are

found in cultures, females lay one egg at a time. The fecundity is not known.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. A decrease in millipede activity occurs as oviposition nears. The percentage of

infested millipedes drops, presumably due to adult mites leaving the millipedes for

oviposition. Both mites and millipedes oviposit at the same time. May through June.

Heterozerconid eggs are laid individually, probably in a series. Freshly laid eggs appear

slightly opaque and gelatinous, with no obvious chorion. With time, the color becomes

uniformly white and the egg appears to firm. Determination of the length of time required

from egg deposition to eclosion was problematic. Three active larvae appeared within 5

days after placing an egg-bearing female into a rearing cup. Facultative larvipary or

ovovivipary may occur in this species. Other laboratory observations of eggs suggest

deposition to eclosion may actually require a longer time.

Upon molting, the immatures actively feed. The larval heterozerconid is at first

undifferentiated and round in appearance. Laboratory observations reveal developmental

time for the larval stage may require from 2 weeks to over a month (N=2, ranges: 14-34

days and 35-41 days).

The protonymph resembles the larva in color and shape but has added a fourth pair

of legs, more seta and is 50% larger. This instar is an active feeding stage and can last

from 18-21 days (N=2).

The deutonymph differs from the previous instars by exhibiting a more elongate

shape and a burgundy shading of the opisthosoma. Laboratory data reveals the

deutonymphal stage lasts a minimum of 21 days. If conditions are not favorable, the instar

length can be extended. In the lab a deutonymphal instar survived four months. It is not

sure whether this was due to a dietary deficiency, or lack of a particular molting stimulus.

Teneral deutonymphs are roughly 50% larger than the protonymph but deutonymphs

approaching a molt may be larger than teneral adults. Prior to molting, the deutonymph

develops a distinct mid-dorsal depression.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Immature Adults

Unsclerotized Highly sclerotized

No ventral suckers Ventral suckers

Hypotrichous, long curly setae Hypertrichous, minute setae

Not attracted to millipedes Highly attracted to millipedes

Never on millipede Sometimes on millipede

Predatory May feed from millipede exudates

Table 3.5: Appearance and behavior differences between immatures and adult

Narceoheterozercon ohioensis (Acari: Heterozerconidae).

The appearance of the teneral adult mites, coincides with the emergence of the

millipedes, following a period of inactivity. Unlike molting in insects, millipedes take

weeks to undergo the process and to recover (Hopkin and Read, 1992), which occurs at

the same time immature mites are developing in accumulations of millipede frass beneath

the bark of decaying logs. The adult heterozerconids appear on the millipedes in late

August to early September, coinciding with renewed millipede activity. At this time, newly

molted heterozerconid adults exhibit their largest yearly densities on the millipedes. Male

mites often briefly outnumber the females. Newly molted adults are lighter in color and

males and females are often difficult to distinguish. Mature female mites appear chestnut in

color and somewhat rounded in appearance, while the males exhibit less sclerotization and

a lighter color.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The long dorsal setae of the immatures have been replaced by minute setae covering the

dorsum. Ventral suckers, only found in the adult mites and pulvilli, provide adhesion to

their host millipedes but the suckers seldom are observed functioning in this manner.

Following the late summer emergence, mating in millipedes and mites coincide.

Mature millipedes then seem to disappear abruptly, suggesting the possibility of postmating

dispersal in this species. Post-mating dispersal has been reported in other Juliformia.

Cylindroiulus punctatus (Leach) was reported to migrate from the logs into the litter

following breeding and into the mineral soil with the onset of cold temperatures (Barlow,

I960). Narceus were reported to overwinter in the upper layers of the soil in the Carolinas

(Rowland Shelley, pers. comm., O’Neill, 1968). In Ohio, both the logs and the soil

beneath known infested logs was investigated during the winter but did not result in the

recovery of any millipedes or mites. Orthoporus omatus (Girard), another juliform

millipede, found in the deserts of the southwestern United States, was reportedly excavated

in large balls of aggregated millipedes during the winter months (Clifford Crawford, pers.

comm.). Isolated aggregations of overwintering millipedes, could increase the difficulty to

locate them. No records of large overwintering aggregations of Narceus have been

reported but data is scarce.

Despite the failure to recover overwintering mites and millipedes, numbers of mites

per millipede for the final collecting session in which millipedes were found, in October

1998, closely resemble those of the first collecting episode in which millipedes were found

in May, 1999. This suggests a continued association with the host, most probably the

mites overwinter on the millipedes (Fig. 3.1).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3.3.4 Invertebrate Community in Millipede Frass

The habitat provided by the millipede provides both food and a humid protected site

for the immature heterozerconids to develop. The millipede frass provides a habitat not

only for the heterozerconid immatures but also for a wide range of predatory mites and

other arthropods. The habitat is formed from uniform round balls of frass produced by the

millipede. In other mites, a “pincushion” arrangement of setae, such as that of the

Diarthrophallidae, provides adequate protection from predators but would not facilitate

movement in such an environment. Although the long idiosomal setae may provide the

immature heterozerconid with some protection from predators, the setae may also provide

further protection in a unique millipede-mediated frass habitat. The interlocking

arrangement is formed when dorsal setae j5 curl posteriorly over the opisthosoma while

setae, S4 curl anteriorly, up over the dorsum from the opisthogaster (Chapter 2). When

these setae interlock, they may provide protection from crushing, as well as preserve

mobility among the accumulation of spherical millipede frass.

A great diversity of arthropods can be found in the frass. To determine their

potential impact on the immature heterozerconids in terms of food and risks, three samples

of millipede frass were collected on the same day in the field, from different logs. All

arthropods were hand picked from each 2 g sample of millipede frass. The combined

millipede frass samples contained approximately 350 arthropod specimens, 2/3 of which

were mites. Fifteen families of mites were represented: 8 predatory, 5 could serve as food,

and the others may be neutral or act as fungivores. The predatory mites included

Laelapidae, Podocinidae, Polyaspidae, Ascidae, Bdellidae, Cunaxidae, Rhagidiidae and

occasionally Uropodidae. Rhagidiidae are small, compared to the heterozerconid

immatures which may eliminate them as a threat and may make the rhagidiids vulnerable to

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. attack by the heterozerconids. Immature heterozerconids have been observed feeding on

immature Oribatida and other small mites. Small mites found in the frass samples include

Acaridae, Tydeiidae, Nanorchestidae and immature Oribatida, all of which may be used as

food for the immature heterozerconids. Besides small mites, larval and nymphal

Heterozerconidae were most often observed feeding on immature Collembola. Oribatida

and Collembola were the two most numerous taxa in the samples. Oribatida represented

50% of the arthropods in the sample (182) and Collembola (112) were second. Arthropods

other than mites and Collembola such as insects and Chilopoda, represented less than 5%

of the total 353 specimens recovered. Their movements through the frass could cause

shifting in the environment and result in the death of the fragile immature heterozerconids.

Immature feeding. The large numbers of Collembola and small mites in the millipede

frass provide food for the immature heterozerconids. Perhaps because of the abundance of

food, cannibalism was never observed in the laboratory cultures, despite observations of

close contact between the instars.

Both the larvae and the protonymphs were observed feeding. The feeding posture

for these two immature instars is the same. Their first pair of spiny legs and palps are held

arched above their bodies resulting in an ambling gait.

The prey appear to be grasped, or supported by the pedipalps (Bhattacharyya,

1962). Large horn-like comicuii only occur in the immatures (Chapter 2) and assist in

grasping prey including immature Collembola and small mites. Prey capture was never

witnessed and the method of capture remains puzzling. Immatures ignored freshly killed

collembollans placed directly in front of them. Collembolan feeders such as Athiasella

dentata Lee, 1973 (Acari: Rhodacaridae), have been reported to “charge” their prey (Lee,

1974) which would necessitate quick movement.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. A more likely method is employed by a prostigmatid mite, Neocaeculus Coineau 1967.

This mite simply stands with upraised legs I and when a collembolan wanders beneath its

legs, they drop to capture their prey (Walter and Proctor, 1999). Nematodes are the most numerous of the frass inhabitants. Nematodes are

considered the most common endoparasite of millipedes (Blower 1985). Nematodes

quickly become established in their host millipedes and in the millipede’s habitat. Despite

their large numbers, nematophagy was never witnessed. The immatures lack the hooked,

tweezer-like digits such as Cheiroseius Berlese described by Karg (1983) as capable of

grabbing nematodes out of crevices. They also completely lack the offset teeth described

by Karg (1983) as indicative of nematophagy. Immature heterozerconids possess only two

teeth including the pilus dentilis on the basal half of the fixed digit. The movable digit does

not possess any teeth but a comblike structure. Their chelicerae appear to be more suitable

for larger prey such as Collembola.

3.3.5 Interactions with the host

Host Attraction. The millipede frass provides a habitat for the immature heterozerconids,

while the adults are found on the millipede hosts. Immatures of Narceoheterozercon

ohioensis have never been collected from millipedes unlike some undescribed South

American heterozerconids. When tested the immatures exhibited no attraction to

millipedes.

Five heterozerconid larvae were individually placed with a millipede, and

movements were observed for signs of host attraction. Each larva was placed on a grid in a

petri dish along with a small millipede. Positive taxis was not observed in any of the

repetitions, even at the distance of .5 cm.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Likewise, newly molted adult mites are not immediately attracted to their hosts

millipede, possibly timed with hardening of their cuticle. Narceus annularis is believed to

be the host preferred by Narceoheterozercon ohioensis. The specificity of this

millipede/mite system was investigated.

Two species ofNarceus were used in the experiment to test for host specificity,

Narceus annularis and Narceus gordanus (Chamberlin), a southern species with a greater

tendency to burrow. In the test, mites placed on an isolated N. gordanus remained there

until a N. annularis was placed into the test chamber, after which the mites switched from

N. gordanus back to their reported host millipede, N. annularis. This test was repeated 4

times with similar results. In all repetitions, the mites left N. gordanus. The recurrence of

mites on N. annularis suggests host specificity. The evolution of this specificity may be

due to a long-term close association in a shared habitat. The life histories of the mite and

millipede coincide.

Feeding. In contrast to the immatures’ predatory style of feeding, both male and female

mites appear to feed from secretions produced by the millipedes. Millipedes are a diverse

source of food for mites, besides direct feeding on the hemolymph as in Narceolaelaps,

(Kethley, 1978) a variety of secretions allow opportunities for feeding.

The millipede’s exoskeleton is punctuated with minute pores. White paint placed

on the laboratory millipedes would discolor within 24 hours. This appears to be due to the

release of some fluid from the cuticle. Adult mites are often observed brushing the

millipede’s cuticle with their palps. This behavior was also reported in the millipede

associates, Paramegistus Tragdrdh 1906 and Neomegistus Trag&rdh (Lawrence, 1939b,

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Trag&rdh, 1907). Like heterozerconids, these mites also possess modified internal malae.

It is possible these mites feed on millipedes exudates.

Besides brushing with their palps, adult mites have also been observed

congregating around wounds on the millipede, suggesting they are also opportunists.

Adult mites have been observed to seemingly emit a drop of fluid onto the cuticle of the

millipede. This behavior is not understood.

Feeding methods are not the same throughout the Heterozerconidae. In a Philippine

species, instead of brushing with their palps, the mite would make broad sweeping

movements across the cuticle of the millipede with its gnathosoma. These methods

represent non-invasive forms of feeding.

Invasive techniques such as piercing of the millipede’s cuticle, have never been

proven in Narceoheterozercon ohioensis and the chelicerae do not appear stylet-like.

Parasitism in the Heterozerconidae occurs in a South American species. Blood was found

in the gut of Zeterohercon amphisbaena Flechtmann and Johnston 1990, an associate of

squamates, suggesting parasitism (Flechtmann and Johnston, 1990).

Adult heterozerconids have never been observed exhibiting predatory behavior or

feeding on anything when off of the millipede. They have however, been observed

drinking water in a petri dish by wiggling their tritostemum in the drop. This also has been

documented in other mites (Wemz and Krantz, 1975).

In Narceus annularis, toluquinone and 2-methyoxy-3-methyl-benzoquinone are the

main components of their defense secretion (Percy and Weatherstone, 1971). A pair of

repugnatorial glands mid-laterally located on both sides of each segment, open to the

surface by ozopores and release the secretion when a millipede becomes disturbed. When a

millipede produces noxious defensive secretions from its repugnatorial glands, the mites

immediately show increased activity and run to areas of safety including the head, collum

(segment following the head) and the legs. It can also cause the mites to leave the host

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. millipede. The millipedes are capable of releasing defense chemicals from selected

segments which suggests the possibility that exudates may also be selectively released

through active solicitation by the mite. The mites may actively solicit exudates or food

from the millipede, by brushing the millipede’s cuticle with its palps, as seen in

Narceoheterozercon ohioensis. Active solicitation is documented in the ant ectoparasite,

Antennophorus grandis Berlese 1904 which actively solicits its host ant, by tapping with

its first pair of legs (Franks et al. 1991).

To understand the mites sensitivity to the defensive secretion, 7 adult mites were

enclosed in a covered petri dish with a small quantity of the yellowish defensive fluid.

After exposure, they first exhibited difficulty walking (in addition to movement difficulties,

their pulvilli appeared to stick to the surface of the petri dish) and soon died. In a mite-

millipede system, not only is avoidance of the defense secretions less costly than

developing immunity, it is advantageous. Maintaining a negative response to the defensive

secretions, encourages the mite to move quickly to safe locations and thus helps prevent

accidental separation from the host. On the other hand developing a resistance to the

defense secretions would not benefit the mites because although they would avoid the toxic

effects, they would not receive the stimulus to seek a safer site.

Mite loading. Millipedes are large compared to most arthropod hosts. They provide a

choice of sites available for ectoparasites. Some sites such as between the legs and in

depressions below the antennae are safe from the toxic defensive secretions.

The millipedes in the Philippines and in Ohio represented two different families

(Rhinocricidae and Spirobolidae respectively). Lengths of male and female millipedes in

the Philippines were virtually equal (females N = 67, mean = 112.3 mm., s.d. ± 7.9 ),

(males N = 48, mean = 108 mm., s.d.= ± 6.3). In the US, both sexes of Narceus were

also virtually the same length (females N = 83, mean = 67.7 mm., s.d. = ± 12.9),

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. (males N = 82, mean = 67mm., s.d.= ± 13). Immature millipedes N = 69, mean = 39

mm., s.d. s ± 8.1.

Mites on millipedes were recorded over parts of 5 years. For the 1998-1999 and

the fall seasons of 200 and 2001, female millipedes (N= 83) possessed 122 male mites and

178 female mites. Male millipedes (N=82) possessed 135 male mites and 137 female

mites. Immatures (N= 69) possessed 21 male mites and % female mites. Overall the sex

ratio of adult mites pooled over female and male millipedes wasn’t significantly different

from a 30:30 sex ratio. However the sex ratio on immature millipedes was significantly

female biased (x2 = 48.08, [d.f. =1], p = <.001). The importance of this is not

understood.

Immature millipedes would appear to be a poor choice for heterozerconids. Mites

on immature millipedes with small diameters would frequently fall off the host millipede,

especially if it were handled; otherwise mites rarely dropped off the host.

Although preference for a particular sex of millipede by heterozerconids is unclear,

there have been reports millipede sex preference. InNeomegistus Trag&rdh 1906 and

Paramegistus Tragirdh 1906 a definite preference for the anterior portion of male

millipedes is reported for both sexes of mites (Lawrence, 1939b). Lawrence attributed the

preference to seminal feeding by the mites.

Field collections for 1997-1999 and portions of 2001 and 2002 resulted in 758

millipedes. Infested millipedes comprised 44% (331) and uninfested 56% (427).

Immature millipedes comprised 13% (109) while adult millipedes comprised 87% (649).

Male millipedes made up 42% of the total millipedes and 47% of the adult millipedes

collected. Female millipedes comprised 45% of the total millipedes and 53% of the adult

millipedes collected.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Female mites appeared to exhibit a mid to posterior location preference, while males

could easily be observed in an anterior location. With the onset of the mite mating period,

this difference became exaggerated and a strict division of the sexes on the millipede was

often seen.

Often prior to the beginning of the mating season of Narceoheterozercon

ohioensis males would briefly outnumber the females but with the onset of the mating

season, the mite sex ratio would near 1:1 and the strict isolation of the sexes would also

disappear. A near 1:1 ratio is achieved through switching from host to host. Switching

from one millipede to another, is risky behavior and can result in the inability to locate

another host. The success rate of switching is increased with the increased contact between

mating pairs of millipedes. This behavior has also been observed in Proctolaelaps Berlese

1923 a flower mite (Colwell et al., 1999) and is believed necessary to establish the proper

ratio of mating mites.

During millipede mating, mite activity on the millipedes increased. Mites ran

rapidly across the dorsum of the millipedes with males mounting and dismounting females.

Except during the mating season, contact between the mites is limited. Lawrence (1939b)

described similar behavior of both Paramegistus Tragardh 1906 and Neomegistus

Trag&rdh 1906 following millipede mating. It is possible that some aspect of mating in the

host millipedes, such as pheromone production, can stimulate mating in their mite

associates. Cross species stimuli eliciting responses (mainly dispersal) has been reported

in other mites. Hypoderatid mites, subcutaneous parasites of birds respond to hormones

released by the bird causing the mites to leave their host in time for dispersal on the

immature birds (Fain, 1967). A cross-species mating stimulus could result in host

specificity.

Millipedes are long-lived. Some species of millipedes are believed to live as long as

10 years (Hopkin and Read, 1992). Experienced, mature millipedes may be more likely to

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. ensure transit to a safe overwintering site and return to well-used communal logs for

oviposition in the spring. Cues received from host arthropods have been discovered to

prepare mites for dispersal by the host. Parasitus copridis Costa 1963 keys into the

allomones produced by the host beetle, Copris hispanus L. as a result of aging and the

activity associated with moving to a new habitat (Costa, 1969).

Artificial conditions in the laboratory can result in more than one generation/year,

with immatures appearing in January. This suggests that although the adults overwinter,

they do not necessarily undergo diapause during this time. Multiple generations also occur

in tropical representatives. Data from Philippine heterozerconids reveals two or more

generations/year, arranged around the rainy and dry seasons whereas in North America it is

arranged around cold and warm seasons.

3.3.6 Tropical Phenology

Host habits Collecting Philippine millipedes (Rhinocricidae) required a different approach

than that required for Narceus in Ohio. Millipedes were collected by brushing away the

leaves accumulating on the forest floor. Although millipedes could also be found in

downed decaying logs, the logs were not widespread. Human intervention and the

accelerated decay rate of a tropical climate were most likely responsible. The distribution of

the Philippine millipedes resembled that in North America except the millipedes did not

aggregate in large groups as had been seen in the United States. Lack of logs for nest sites

may explain the apparent lack of aggregation by the millipedes. Lack of aggregation may

result in changes in the mite/ millipede relationship.

The mites appeared to have 2 generations/year with two large peaks of mites

occurring in March and in July (Fig. 3.2). Immature mites also show 2 main peaks of

activity (Fig. 3.3).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Although a cool and relatively dry period occurs in December and January it is not

as a severe climatic change as the winter /summer seasons in the temperate zone. Trends

were therefore more difficult to distinguish than in the Ohio study site.

Samples of mites removed from individual millipedes often include teneral mites as

well as older more sclerotized mites. This could indicate a wide range for each life stage or

overlapping generations. The 2 peaks of mites seen in the adult mites in the Philippines

may correspond to the single peak seen in teneral adults occurring in Ohio species in late

August and early September (Fig. 3.2). If this is the case, these peaks seen in Philippine

adult mites, should represent the onset of the breeding season.

Tropical Temperate

2 to 3 generations Univoltine

widespread millipede distribution patchy millipede distribution

wet/cool season cold/dry season

millipedes in Los Banos not aggregating millipedes in Little Rocky Hollow aggregate

millipedes oviposit in litter millipedes oviposit in logs

millipede frass in piles, in litter millipede frass in isolated pockets of logs

immature heterozerconids in frass immature heterozerconids in frass

immatures unlike adults in appearance immatures unlike adults in appearance

millipedes found mating multiple times millipedes mate only once in autumn

during the year

Table. 3.6: Comparisons in a tropical and temperate mite/millipede association.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Mating in the Philippine millipedes was not a single event as in the Ohio species

which could indicate overlapping generations. Immature heterozerconids were found in

patches of millipede frass among the litter, rather than isolated in rotten logs as in North

America. Mites collected in the Philippines were equivalent in numbers to 70% of the total

number of mites collected during the study period covering parts of 5 years in Ohio.

Records of mite loading in the Philippines, showed female millipedes (N= 67)

carried a total of 384 mites (216 male mites and 168 female mites), while male millipedes

(N= 48) carried a total of 388 mites (188 male mites and 205 female mites).

A dry and cool period occurs in December and January in Luzon, the island where

the mites were studied. A drop in millipede activity occurs during this time.

3.4 CONCLUSIONS

In the tropics, populations of mites were larger. This is at least due in part to more

than a single generation of mites/year, as well as widespread host range with host

millipedes more numerous than in the temperate zone. Conversely large numbers of mites

are not possible in the Ohio species because of the limitations of 1 generation/year, low

numbers of eggs produced by the females, limited numbers of millipedes and severe

climatic conditions requiring hibernation by the millipedes. Humidity is the main limiting

factor affecting distribution of millipedes (O’Neill, 1968). In the tropics, widespread

humid conditions increase habitat availability, thus promoting a large population of

millipedes.

In the temperate climate, the strict regime of the single generation/year forced a

synchrony not evident in the Philippine mites. Increasing dependency and the development

of intricate relationships in temperate regions has been noted in other animal and plant

groups (Norton and Carpenter, 1998). The relationship between Heterozerconidae and its

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. host millipedes is a complex one. This single generation/year is extremely vulnerable due

to the number of variables affecting the system, including weather and log resources.

Heterozerconid populations flourish in undisturbed areas and are fragile. Isolated

relict populations are dependent on the success of their millipede host and may be adversely

affected by disturbance. Further fragmentation of habitats through human intervention can

lead to extinction.

Data gathered on the biology of the Heterozerconidae has revealed an astounding

amount of dependence by the mite on its host millipede. Some of the behavioral

observations presented, are undoubtedly rarely witnessed and therefore chances for

duplication may be slim. The relationship between Narceoheierozercon ohioensis and its

millipede host, Narceus annularis is worthy of further study.

3.5 ACKNOWLEDGMENTS

The tropical data presented in this study was made possible by financial aid

provided by the Fulbright Foundation and the Philippine American Education Foundation.

Thanks to Dr. Rowland Shelley, Dr. Clifford Crawford for sharing their knowledge of

millipedes and Dr. John Furlow for sharing his assistance in the tree transects and sharing

his botanical knowledge. Thanks also for helpful suggestions from Rodger Mitchell and

Dana Wrensch. My appreciation for the use of laboratory facilities provided by Dr. Leonila

Corpuz-Raros and the UPLB Entomology Department (University of the Philippines at

Los Banos). The kindness and encouragement shown by Dr. Mercedes Delfinado-Baker

was greatly appreciated. Thanks to Lourdes, Drs. June and Lorie De Pedro and Dr. Lina

Villacarlos and Noli Almeroda of VISCA. Thanks also to Alex and Butchie Amor, for

direction on my Visayan journeys. My sincere gratitude to Phin Garcia, whose expertise in

acarology and the filipino culture made for an unforgettable journey through the islands.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 3 .6 LIST OF REFERENCES

Baneijee, B. 1967. Seasonal changes in the distribution of the millipede Cylindroiulus punctatus (Leach) in decaying logs and soil. J. Animal Ecol., 36: 171-177.

Barlow, C.A. 1960. Distributional and seasonal activity in three species of diplopods. Ark. Neerlandaises Zool., 13: 108-133.

Bhattacharyya, S. L. 1962. Laboratory studies on the feeding habits and life cycles of soil inhabiting mites. Pedobiologia, 1:291-298.

Blower, J. G. 1969. Age-structures of millipede populations in relation to activity and dispersion. Systematics Assoc. Publ., 8: 209-16.

Blower, J. G. 1970. Notes on the life histories of some British Julidae, Bull. Mus. Nat. Hist. Naturelle, 41: 19-23.

Blower, J.G. 1985. Millipedes. Linnean Society Synopses of the British Fauna (New Series):35. E. J. Brill and Dr. W. Backhuys, London. 242 pp.

Colwell, R.K., and S. Naeem. 1999. Sexual sorting in hummingbird flower mites (Mesostigmata: Ascidae). Ann. Entomol. Soc. Am., 92:953-958.

Costa, M. 1969. The association between mesostigmatic mites and coprid beetles. Acarologia, 11:411-428.

Crawford, C.S., and M.C. Matlack. 1979. Water relations of desert millipede larvae, larva-containing pellets, and surrounding soil. Pedobiologia, 19:48-55.

Crawford, C.S., K. Bercovitz and M.R. Warburg. 1987. Regional environments , life history patterns, and habitat use of spirostreptid millipedes in arid regions. J. Linn. Soc. (Zool.) London, 89: 63-88.

Fain, A. 1967. Symposium on adaptive radiation in parasitic acari: Adaptation to parasitism in mites. Acarologia, 11:429-448.

Flechtmann, C H.W. and D.E. Johnston. 1990. Zeterohercon, a new genus of Heterozerconidae (Acari: Mesostigmata) and the description ofZeterohercon n. sp. from Brasil. Int. J. Acarol., 16: 143-147.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Franks, N.R., K.J. Healey and L. Byrom. 1991. Studies on the relationship between the ant ectoparasiteAntennophorus grandis (Acarina: Antennophoridae) and its host Lasius flavus (Hymenoptera: Formicidae). J. Zool. (Lond), 225: 59-70.

Hopkin, S.P. and H.J. Read. 1992. The Biology o f Millipedes. New York: Oxford University Press, 233 pp.

Karg, W. 1983. Verbeitung und bedeutung von raubmilben der cohors Gamasina als antagonisten von nematoden. Pedobiologia, 25:419-432.

Keeton, W. T. 1960. A taxonomic study of the millipede family Spirobolidae (Diplopoda: Spirobolida). Mem. Amer. Ent. Soc., 17: 1-146.

Kethley, J. B. 1974. Developmental chaetotaxy of a paedomorphic Celaenopsoid, Neotenogynium malkini n.g., n.sp. (Acari: Parasitiformes: Neotenogyniidae, n. fam.) associated with millipedes. Ann. Ent. Soc. Amer., 67: 571-579.

Kethley, J. B. 1978. Narceolaelaps n.g. (Acari: Laelapidae) with four new species parasitizing Spirobolid millipedes. Int. J. Acarol., 4: 195-210.

Krantz, G. W. 1978. A Manual of Acarology. Ed. 2. Corvallis: Oregon State University Book Stores, 509 pp.

Lawrence, R.F., 1939a. A new mite attached to the sex organs of South African millipedes. Trans. Roy. Soc. S. Africa., 27: 225-231

Lawrence, R. F. 1939b. Notes on the habits of the two mites living on South African millipeds. Trans. Roy. Soc. S. Africa., 27: 233-239.

Lee, D. C. 1974. Rhodacaridae (Acari: Mesostigmata) From near Adelaide, Australia HI. Behaviour and development. Acarologia, 16:21-44.

Lizaso, N. M., 1978/79. Un novo acaro da familia Heterozerconidae coletado sobre serpentes brasileiras. Descricao de Heterozercon elegans sp. n. (Acarina, Mesostigmata). Mem. Inst. Butantan, 42/43: 139-144.

Norton, D.A. and M.A. Carpenter. 1998. Mistletoes as parasites: host specificity and speciation. TREE, 13: 101-105.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. OConnor, B. M., 1982. Evolutionary ecology of astigmatid mites. Annu. Rev. Entomol., 27: 385-409.

O’Neill, R.V., 1968. Population energetics of the millipede Narceus americanus (Beauvois). Ecology, 49: 803-809.

Percy, J. E. and J. Weatherstone. 1971. Studies of physiologically active arthropod secretions. V. Histological studies of the defence mechanism of Narceus annularis (Raf.) (Diplopoda: Spirobolida). Can. J. Zool., 49: 278-279.

Trag&rdh, I., 1907. Description of two myriopodophilous genera of Antennophorinae, with notes on their development and biology. Arkiv. for Zoologi., 3: 1-34.

Walter, D. E. and H. C. Proctor, 1999. Mites, Ecology, Evolution and Behaviour. C. A. B. I. New York, NY. 322 pp.

Wemz, J.G. and G.W. Krantz, 1975. Studies on the function of the tritostemum in selected Gamasid (Acari). Can. J., 54:202-213.

Wolfe, J. N., R. T. Wareham and H.T. Scofield. 1949. Microclimates and macroclimate of neotoma, a small valley in central Ohio. Ohio Biological Survey, Bull. 41. Vol. 8: 1-267.

%Milipedes infested 100-1 0 9 - 0 6 - 0 7 80- * O * * H 40 | - 0 5 30- 0 2 10 rvlne 97 Prevalence * - - -

------Figure 3.1: Figure rvlne O 8 9 Prevalence ° rvlne # 9 9 Prevalence • Narceoheterozercon ohioensis. Narceoheterozercon olcig dates Collecting * ° ° « • * * v • O 85 Prevalence 1997-1999. Ohio, USA Ohio, 1997-1999. Prevalence x m

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^ Philippine

X Ohio

Figure 3.2: Intensity. Heterozerconidae adults/millipede. Philippines (2001), Ohio, USA (1999).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 8-

7 -

6- tfi« .« Z 5- O □ s 5 S 4-1

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2- □ O □ □

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Collecting Dates

O larvae

® protonymphs

O deutonymphs

Figure 3.3: Total numbers of Philippine immature Heterozerconidae/total samples/collecting date.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. CHAPTER 4

Diversity of Spermatodactyls and Mating Systems Within the Heterozerconidae

4.1 INTRODUCTION

The Acari are a highly diverse, highly successful, cosmopolitan group of

arthropods. They are composed of two major groups, the Acariformes and Parasitiformes.

Two reproductive conditions exist in the Acari, indirect fertilization and direct fertilization.

Indirect fertilization involves the deposition of a spermatophore on the substrate by the male

with relatively little necessary interaction between the sexes. The mites may be active in

similar habitats, where pheromones direct the female to the spermatophore. It can also

involve behavioral modification, with the male directing the female to the spermatophore

through a courtship dance. The female reproductive system has a single opening, a

gonopore, for sperm entry and egg exit. Indirect fertilization occurs only in the

Acariformes.

Direct fertilization involves a shift to complex mating behaviors directing

insemination. This method requires the male to actively transfer the spermatophore to the

female gonopore, to insure fertilization. Direct fertilization occurs in both the Acariformes

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. and Parasitiformes. In the Acariformes, it includes a morphological modification in the

male, the evolution of an intromittent organ or aedeagus for insemination (Evans, 1992).

Like indirect fertilization in the Acariformes, the gonopore is also the ovipore.

In the Parasitiformes, direct fertilization does not necessarily require modification of

the reproductive organs, or the evolution of an intromittent organ. In the primitive

condition, the male places the spermatophore with unmodified chelicerae into the primary

gonopore/ovipore of the female. This is tocospermy (Athias Henriot, 1968). This is the

condition in all the Parasitiformes (also hypothesized to be the condition in the Holothyrida)

with the exception of the Parasitina, Dermanyssina and Heterozerconina. In the Parasitina,

Dermanyssina and Heterozerconina, direct fertilization is accompanied by modifications in

the reproductive organs. The least modifications occur in the Parasitina, where males

possess a foramen or spermatotreme on one side of the movable cheliceral digit (Evans,

1992). The spermatotreme is thought to receive the neck of the spermatophore which is

then positioned at the primary gonopore of the female (Evans, 1992). Because the

destination of the spermatophore is the primary gonopore/ovipore of the female as in the

majority of the Parasitiformes, this method is considered tocospermous.

In the suborder Dermanyssina, modified secondary sex structures occur in both the

female and male. In the more derived condition, the gonopore is utilized only as an ovipore

while the female develops an alternative, secondary sperm access system with an external

pore or solenostome for sperm entry. The solenostome commonly occurs near coxae ID or

IV. For this reason, it is termed podospermy (Athias Henriot, 1968). Podospermy

requires an elaborate modification of the male chelicerae, a spermatodactyl, for the

placement of the spermatophore or its contents into the alternative genital opening or

solenostome of the female. Podospermy occurs in the Dermanyssina and is reported to

occur in the Heterozerconina. In the Dermanyssina, the male possesses an elongate

appendage or spermatodactyl, derived from the movable digit with a canal running its

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. length (Evans, 1992). The male inserts the spermatodactyl into the female solenostome and

the contents of the spermatophore travel down the canal and enter the female.

The function of the spermatodactyl as a sperm transfer device has been confirmed in

some Dermanyssina (Young, 1968). Within Heterozerconina, Heterozerconidae possess a

device fitting the description of the spermatodactyl in the Dermanyssina but occunring on

the opposite digit, the fixed digit. The spermatodactyl in the Heterozerconidae is assumed

to be a sperm transfer device based on its appearance. A secondary sperm access system in

the Heterozerconidae is a preconception based on the presence of the spermatodactyl in the

male, yet no exact location for a solenostome has ever been confirmed. In this paper, I

intend to present observational and morphological evidence confirming the function of the

spermatodactyl in the Heterozerconidae as a sperm transfer device and exact location of the

solenostome in a female North American heterozerconid. A hypothesis for the origin of the

spermatodactyl will allow an explanation for the diversity of spermatodactyls in the

Heterozerconidae and their subsequent division into zoogeographic regions

4.2 MATERIALS AND METHODS

4.2.1 Collecting/Rearing Techniques

The heterozerconid Narceoheterozercon ohioensis (Chapter 2) was collected from

the millipede, Narceus annularis (Rafinesque) (Diplopoda) under bark of logs in Hocking

County, Ohio, U.S.A.( 39° 28’59"N, 82° 50’ 51” W). Cultures of millipedes with mites

were maintained in plastic containers on a substrate of milled sphagnum.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 4.2.2 Specimen Study Techniques/Preparation and Measurements

Live heterozerconid specimens were observed under a dissecting microscope.

Mating was recorded on SVHS tapes and deposited in the Acarology laboratory at The

Ohio State University.

Slide specimens were cleared in lactophenol and mounted in Hoyer’s medium

(Krantz, 1978). Specimens were studied with phase contrast and differential interference

contrast systems. Scanning electron images were made on a Phillips scanning electron

microscope. Drawings were made with a camera-lucida on a Zeiss Axioskop compound

microscope. Inked drawings were scanned and prepared, using Adobe Photoshop

Graphics Program. All measurements are presented in micrometers (pm).

4.2.3 Material examined

The following specimens were observed. Unless otherwise noted all specimens are

Heterozerconidae: Australia, Queensland, 18-IV-97, Discozercon (1M, IF); Belize, Cayo,

26-VI-99, OSAL005743 (IF); Eastern Borneo, FMNH EBM-I, H-143 (IF); Brazil,

Zeterohercon amphisbaena type (IF); Central African Republic, Bayanga, 6-VII-98,

OSAL 005540 (1M, IF), Costa Rica, La Selva, UMMZ BMOC 96-1105-214 (1M, IF),

Cote D’Ivoire, Comoe National Park, OSAL 006577 (1M, IF), OSAL 006578 (1M, IF),

OSAL 006579 (1M, IF); Ecuador, FMNH FMJK-71-118 (1M); Gabon OSAL 006492

(1M, IF); India, Karnataka 12-17-IX-77, OSAL 005793 (1M); Kenya, Kwabe, Makadara

Forest, 22-VIII-96, OSAL 005017, OSAL006109 (IF); Madagascar, Antsiranana, 20-27-

1-01, OSAL 006878 (2M, IF); Malaysia, Pahang, 1 1-01-67 (IF) FMNH H-161, Kuala

Krau 23-0-71 FMNH H-158; Mexico, Quintana Roo, Sian Kaan 5-IX-95, #578 (1M), 23-

VO-98 (IF); Philippines, Bohol, 13-VI-00, OSAL 006374 (1M, IF); Leyte, VISCA 7-VI-

00, OSAL 006202 (2F), OSAL 006110 (1M); Luzon, Ifagau, 3-01-00, OSAL 006090

(1M), OSAL 006107 (2F); Luzon, Los Banos, UPLB Forestry Campus 21-ID-00, OSAL

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. 006107 (2F); Mindoro, Baet, 20-VH-00, OSAL 006113 (1M), Bulalacao, 22-VH-OO,

BSG00-722-3 (1M), Rizal, 24-VII-00, BSG00-0724-1A (1M, IF), Negros, Danao lake,

l-Vn-00, (2M); Panay, Lambunao, 11-VII-00, OSAL 006133 (IF), Samar, Sohoton

Cave, lO-VB-OO, OSAL 006368 (1M, IF), Siquijor, Cansayang, 26-VI-00, OSAL

006138 (1M, IF); Tanzania, Kisarawe, 8-HI-74, Howell co. (1M), Mazumbai, 1-1-81,

OSAL 005602 (IF), Morogero district ,Uluguru Mtns. 27-IV-80, KMH 1380-82 (1M,

IF), Pugu Forest Reserve, 3-II-78, KMH 651 (1M, IF), HK 98-10254 (1M); Thailand,

Bangkok, Chulalongkom Univ., 30-IV-00, OSAL 006109 (1M, IF), BSG98-1118-1

(1M, IF), Ne. Laem Son Koh Phangam, 30-XD-87, Sloan and Boonard col.(lM, IF),

‘Tropics”, ex: arthropod cultures, Mathysse (1M, 2F); Venezuela FMNH Ven 71-3 (2M,

IF); USA, Alabama, Lee County 29-XI-97 AUEM APT-97-1129-2 (1M, IF), Macon

County, 8-VI-85, AUEM RDC-85-0608 (1M, IF), Winston County, Bankhead Nat.

Forest, Sipsi R. Wilderness area 28-111-87, (IF); Illinois, Madison County, Kaufman,

FMNH 7-1971 (1M, IF), Kansas Oregon State University, EK520530-1(2F); Louisiana,

Marrero, 11-1-29 USNMH 104173214 (IF); Ohio, Hocking County, Little Rocky Hollow,

12-IX-97 OSAL 005320 (1M), 24-IX-99 OSAL 006440 (IF); Virginia, Castleman Ferry,

27-IX-27, USNMH 2022968,(IF).

4.3 RESULTS AND DISCUSSION

Mating in Narceoheterozercon ohioensis

Female reproductive system Through observations of mating in a Nearctic species of

heterozerconid, Narceoheterozercon ohioensis, the novel site for the secondary genital

opening in that genus was determined to be in the inner anterior comer of each ventral

sucker of the female.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The solenostomes and associated ducts are highly sclerotized and arch towards the

midline of the female’s genito-ventri-anal shield. This location, well behind the fourth pair

of legs, represents one of the most posterior insemination sites in the Mesostigmata.

Located internally between the solenostomes, a wrinkled membrane, presumably the

spermatheca, is visible.

Pre-Mating Behavior Narceoheterozercon ohioensis males possess long, smooth,

tapering, recurved spermatodactyls, approximately 1/3 of their body length. Because they

arise from the dorsal or fixed digit and are severely recurved, they must be stored below the

dorsum rather than retracted. Prior to mating, the spermatodactyls become noticeable,

conspicuously arched in a posterior direction above the dorsum. At this same time, a

cluster of dark black spots appears right of center on the male’s dorsum. The dorsal

location of these spots corresponds to that of the testis in some Mesostigmata (Alberti and

Coons, 1999). It is possible that these black spots represent a final stage of maturation of

the spermatozoa prior to mating.

In Held observations of mating, the males appeared excited and could be seen

running quickly across the dorsum of the millipede, especially the anterior region, or

collum. Mites were seen to mount one another but mating was not witnessed. Similar

excited behavior has been reported in the millipede associates, Paramegistus Trag&rdh

1906 and Neomegistus Tragardh 1906 (Lawrence, 1939b).

Mating In the lab, heterozerconid mating was observed in a petri dish. The male appears

to search for a receptive partner by tapping females with his first pair of legs. Once a

female responds by becoming quiescent, the male begins mating. Mating varies in time

from approximately 2 to 10 minutes. The male mounts the female (she is immobile), taps

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. the edge of her dorsum, then turns around, swings himself under and assumes a venter to

venter position, facing the same direction as that of the female.

The position he assumes differs from the skewed podospermal position. His body

is situated in the middle of the female in a direct line with hers. His first pair of legs cling

to the female between her gnathosoma and first pair of legs. The male’s legs II-TV cling to

the female, interlaced between her legs H-IV. The male spends a short period of time at

this location, then moves to a more posterior position, below the level of coxae IV. With a

flexed gnathosoma, he performs vigorous thrusting movements in the center of the

female’s genito-ventri-anal area. The position of the mating mites prevented the actual

viewing of spermatophore retrieval and placement. The spermatodactyl’s placement in the

novel fertilization site was verified in an undescribed species of Narceoheterozercon. A

portion of a spermatodactyl remained in one of the sclerotized ducts arising from the inner

anterior comer of the sucker.

The unique position of the solenostomes in Narceoheterozercon with anteriorly

directed ducts, reflects the unusual geometry of the spermatodactyls on the fixed digit. The

male first flexes his gnathosoma posteriorly. In that position the recurved spermatodactyls

will be directed anteriorly to encounter the solenostomes in the comer of the suckers. In

most other podospermous mites, the solenostomes are directed posteriorly. Insertion into a

podospermal site in the coxa would not be possible with this peculiar position and shape of

spermatodactyl.

On completion, the male leaves the female and grooms while the female remains

immobile. Following mating, a dark spot appears in the middle of the venter of the female,

between the ends of the ducts arising from the solenostomes. Multiple matings were not

observed.

Confrontations between males were rare. Only once was a male observed climbing

on the back of another male. The harassed male reached as far back with his first pair of

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. legs as possible, trying to dislodge the aggressor. The male on top dismounted, turned

around and pushed the male mite. The mite receiving the pushing simply moved forward

in avoidance. In contrast, more aggressive confrontations were reported in some

Philippine species (pers. comm. Rufino Garcia). The large spines on the femurs of the

second legs in Oriental species may aid in fighting.

These observations confirm podospermy and the use of the spermatodactyl as a

sperm transfer device in the Heterozerconidae. The exact location of the solenostome in the

genus Narceoheterozercon is the first for the Heterozerconidae.

Due to the variety of reproductive structures observed in the Heterozerconidae

however, this observation of mating in a Nearctic species, Narceoheterozercon, should be

considered an example of one type of mating rather than representative of the entire family.

4.3.1 The fixed digit

In the literature, the entire suborder Heterozerconina is reported to be

podospermous. The Heterozerconidae possessed a spermatodactyl on the fixed digit and

the Discozerconidae, one on their movable digit (Domrow 19S6, Krantz 1978, Evans

1992). In this study, the presumed spermatodactyl of the Discozerconidae was discovered

to be a membrane on the movable digit of Discozercon sp., homologous with that of the

Heterozerconidae. Since the Heterozerconidae already possess a spermatodactyl on the

fixed digit, it is unlikely that this structure is also a spermatodactyl. Based on the present

consensus of the terms and conditions of tocospermy and podospermy (Athias-Henriot,

1968), the Discozerconidae should be considered tocospermous. Tocospermy and

podospermy may occur together in the Heterozerconina.

The Heterozerconidae spermatodactyl is on the fixed digit. The remaining

spermatodactyls are all found on the movable digit of taxa in the suborder Dermanyssina.

Because the spermatodactyls are on opposite cheliceral digits in these two suborders,

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. virtually no one believes they are closely related. In order to determine the relationship

between the Heterozerconina and the Dermanyssina and differences if any in the origin of

their spermatodactyls, it is necessary to thoroughly investigate the placement of the

spermatodactyl on the fixed digit in the Heterozerconidae.

The fixed digit in the Dermanyssina usually possesses three sensillar structures. A

dorsal cheliceral seta, a pilus dentil is and an apical “pit” sensillus (Evans, 1992). The

function of the latter two structures is uncertain, but the pilus dentilis is thought to be a

mechanoreceptor and the apical pit sensillus may be gustatory in function (Evans, 1992).

An investigation of the fixed digit inNarceoheterozercon ohioensis reveals the

presence of a spot or pore at the end of the spermatodactyl which may correspond to the

apical sensilla in the Dermanyssina. The presence of this spot has not been verified in any

other members of Heterozerconidae nor in the Discozerconidae. The investigation has also

revealed the presence of three other structures on the fixed digit in the Heterozerconina.

One of these, the dorsal seta, is easily visible in both the Discozerconidae and

Heterozerconidae. A comparative study between the fixed digits in the Heterozerconina,

will focus on the remaining two structures. The results of this comparative study are

preliminary. They are based on light microscopy of available specimens and form a

hypothesis explaining the variety of spermatodactyls in the Heterozerconidae.

The structures to be compared, are most easily seen in the unmodified fixed digit of

the Discozerconidae (Fig. 1: pd and cs). The pair of structures are aligned in a vertical

row, near the base of the fixed digit. In the Discozerconidae, the distal structure is the pilus

dentilus (Fig. 1: pd). Both appearance and location of the pilus dentilis are similar to that in

other Mesostigmata. The structure below the pilus dentilis is much smaller and ends in a

curl rather than the setiform appearance observed in the pilus dentilis. The function of this

minute curled structure is not known.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. The spermatodactyl located on the fixed digit of the Heterozerconidae appears to

arise from the pilus dentilis and the lower curled structure. The varied shape and

appearance of the spermatodactyls exhibited by the Heterozerconidae, seem to be affected

by changes in these two associated structures and occasionally in some species, by a

membrane surrounding the chelicera or an individual digit. The two structures arising from

the fixed digit, can vary in length and fuse in different ways. For instance in a specimen

from Gabon (Fig. 2C: pd), the pilus dentilis appears to have lengthened and migrated to a

more ventral position. It may also appear similar in size and shape to that in the

Discozerconidae. This condition occurs in some Oriental species (Fig. 3B: pd).

In the Heterozerconidae, a structure similar to the curled structure in the

Discozerconidae (Fig. 1 A, B: cs), appears to affect the spiraling of the heterozerconid

spermatodactyl. The spiraling may result in a very tight coiled spermatodactyl as in a Cote

D’Ivoire specimen (Fig. 2A) or it may be very relaxed as in those from Thailand (Fig. 3B).

The spiraling may be confined to the base of the spermatodactyl in species from the

Philippines (Fig. 3D) in the “Old World” and that of Costa Rica in the “New World” (Fig.

4A). In the Nearctic, the spiraling may be confined internally such as in

Narceoheterozercon (Fig. 5A, C).

The varieties of spermatodactyls resulting from changes in the structures associated

with the fixed digit in the Heterozerconidae, are the basis for recognizing the four major

groups of spermatodactyls. These groups correspond to four major geographic regions: 1.

African (Fig. 2), 2. Oriental (Fig. 3), 3. Neotropical (Fig. 4), 4. Nearctic (Fig. 5).

4.3.2 Spermatodactyl Diversity in the Heterozerconidae

African The specimens from this region are similar in the degree of coiling in the

spermatodactyl and appearance of the movable digit. The spermatodactyl may assume a

tightly coiled, often spherical shape (Fig. 4.2A). The movable digit in all specimens

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. observed except Cote D’Ivoire, has a stout heavy appearance (Fig.4.2B-E). Compared to

other specimens observed from the African region, those from Gabon (Fig.4.2C) exhibited

a lengthening of the spermatodactyl.

Oriental The spermatodactyls are longer than those from the African region (Fig.4.3).

Coiling may be confined to the base (Fig. 4.3D) or uniform throughout the length of the

spermatodactyl (Fig. 4.3B).

The longest spermatodactyls were on an undescribed species from Borneo

(Fig.4.3F). The spermatodactyl measured 770 |im in length, while the remaining portion

of the cheiicera is only 100 pm.. In this species, twisting or coiling of the spermatodactyl

appears to occur only near the base. These long chelicerae are stored internally, by

retraction to the posterior edge of coxae IV, similar to that inDinychus Kramer 1886

(infraorder Uropodina), (Krantz, 1978). A membrane (Fig. 4.3F: me) surrounding the

chelicerae, is visible in many Oriental species.

Neotropical Specimens from this region appear to be of two types. One, rigid and

straight in appearance, the other crooked and exhibiting a flaccid distal portion.

Zeterohercon amphisbaena Flechtmann and Johnston, 1990 (Fig.4.4B) possesses the

flaccid type and is a reptilian associate but similar appearing spermatodactyls can be found

in a species associated with millipedes (Fig.4.4A). Shape of the spermatodactyl, therefore,

does not appear to be specific to the host association. The straight, rigid form of

spermatodactyl can be seen in some specimens from Ecuador (Fig. 4.4E).

Nearctic Two genera of Heterozerconidae have so far been found to occur in North

America. Narceoheterozercon (Fig. 4.5A, C) and an undescribed genus (Fig. 4.5B).

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. These genera have a highly sclerotized, recurved spermatodactyl. This level of

sclerotization in the spermatodactyl is mirrored in the female with her corresponding

heavily sclerotized sperm access system (Fig. 4.7).

The spermatodactyls seen in these four geographic regions represents a surprising

diversity based on the proposed origin of the spermatodactyl in the Heterozerconidae.

4.3.3 Diversity of Female Reproductive Systems in the Heterozerconidae

No major secondary modifications of the female reproductive system have evolved

with tocospermy other than development of genital sclerites, such as those occurring in the

Parasitina, Uropodina amd Zerconina. The function of the genital sclerites is unknown and

they are simply defined as sclerotized structures lying beneath the genital shield and thus far

considered unique to tocospermous taxa (Evans, 1992).

Podospermy, or placement of the spermatophore into a secondary genital opening

(sgo) instead of the primary opening, requires modifications of reproductive structures in

both sexes. All male heterozerconids presently known possess a spermatodactyl. Presence

of a spermatodactyl in a male assumes the presence of the podospermous condition

(Alberti, 1984). Podospermy in the Heterozerconidae was verified in all four geographic

regions mentioned above. Light microscopy of “Old World” heterozerconids, revealed

highly sclerotized solenostomes near coxae IV in species from the African region and vague

sclerotized structures in the coxal IV region of some Oriental female heterozerconids. In

“New World” heterozerconids, a broken spermatodactyl was discovered in the female

genital ducts located in the region of the suckers of a Nearctic specimen verifying

podospermy in the Neotropical region. An analysis of reproductive characteristics for each

zoogeographic region will be discussed.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. African In the African specimens observed, the female heterozerconids possessed highly

sclerotized solenostomes in the posterior margin of leg IV or near leg IV on the closely

associated metapodal shields. In addition, indistinct sclerotized structures can be seen

anteriorly located beneath the genital shield in some species.

In female heterozerconid specimens from Madagascar, a spermatheca arises from

the posterior edge of Coxa IV (Fig. 4.8). A chain of bead-like structures emerges from one

side of the spermatheca. This chain-like structure is directed posteriorly. Towards the end

of the chain, the individual structures become more indistinct and appear deflated.

Oriental In Thailand, several species of Heterozerconidae are present. One undescribed

species has an indistinct flask shaped structure inside coxae IV. Because they are only seen

in females, they are assumed to be reproductive structures. This would suggest

podospermy. In other specimens from Thailand, the opening of the sperm access system

in the female, has not been determined. Coinciding with the lack of a visible sperm access

system or solenostome, are the presence of numerous structures resembling large

spermatophores inside the female. In Acarine taxa possessing spermatophores, the external

portion remaining outside the female is termed the ectospermatophore and the portion

entering the female is termed the endospermatophore. In the heterozerconid from Thailand,

I will use the designation spermatophores pending the verification of an

ectospermatophore. In this heterozerconid specimen, the spermatophores were located

internally, near the anterior sternal region of the female. A different location, such as near

the coxae, might have suggested they were originally placed in a spermatheca as in the

Madagascar females. These presumed spermatophores appear too large for entry through a

solenostome. In addition, a structure resembling that of the plug found in the

ectospermatophores in the tocospermous order Ixodida (Evans, 1992), appears centrally

100

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. located inside the female. Very dark genital sclerites are visible in a more posterior location

and more distinct than those of some African specimens.

Some female specimens from Thailand contained as many as 40 eggs. It was

possible to dissect fully formed embryos from their eggs. Close observations revealed

each egg possessed a cord. Stalked oocytes occur in ovaries of some tocospermous taxa,

Uropodina and Sejina (Michael, 1892). In the Oriental region, a transition between the

primitive tocospermy and the more advanced podospermous state is hypothesized to occur.

Podospermy was found to occur in other Oriental specimens. On Leyte in the

Philippines, poorly sclerotized structures are visible in the coxal IV region. This suggests

podospermy as the reproductive method in this species.

An undescribed species from Borneo, was found to be podospermous. The

method differs from that of podospermous taxa from the African region. It does not

involve highly sclerotized solenostomes, instead a long thin structure appears to be coiled

into (Fig. 3E) the femoral region of leg IV in the female. This method is similar to that

which occurs in the rhodacarid, Geogamasus howardi Lee 1970 (Lee, 1970).

Neotropical In some Neotropical species, the secondary genital opening has not been

confirmed. In Zeterohercon oudemansi (Finnegan 1931) presents conflicting

characteristics, a faint slit on the posterior of coxae IV along with a reported genital aperture

between coxae IV. This proposed genital aperture for the genus was not supported in

Zeterohercon amphisbaena by Flechtmann and Johnston 1990 who discovered the

spermatheca lying between coxae IV (Flechtmann and Johnston, 1990) but failed to find

the location of the genital aperture. If this genus is podospermous, it lacks the easy

diagnostic highly sclerotized solenostomes as those in the African region.

In other Neotropical species, a new location for the secondary genital opening

occurs. In some specimens from Central America and Southern Mexico, the solenostome

101

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. is associated with the sucker area. In a Costa Rican specimen, it appears to lie in the cup

beneath the sucker. In a Brazilian species, structures resembling solenostomes can be

found posterior to the suckers in the females.

Nearctic One genus from North American, Narecoheterozercon appears to exhibit the

most derived podospermic reproductive system yet discovered in the Heterozerconidae.

Not only has a new secondary genital location evolved but it has become highly sclerotized.

In this system, solenostomes are located in the inner anterior comer of each female sucker

(Fig. 4.7). Arising from these solenostomes are highly sclerotized tubes-.

4.4 CONCLUSION

The Heterozerconidae exhibit an enormous diversity in spermatodactyls for a single

family. All the different shapes appear to have evolved from lengthening and fusion of

various elements of the fixed digit. This morphing of a basic design has led to recognizable

trends within regions. These regions are representative of both the Old World and New

World.

The diversity of spermatodactyls exhibited by male heterozerconids raises the

possibility of a corresponding diversity in female reproductive methods. Evidence for

podospermy includes both morphological and behavioral. Evidence also suggests a

transition state between podospermy and tocospermy in the Oriental region.

The spermatodactyl in the Heterozerconidae is confirmed as a sperm transfer device

as well as the occurrence of podospermy in a Nearctic species. Morphological evidence for

a transition state includes the presence of spermatophores, “plugs”, genital sclerites and

stalked oocytes as well as the lack of a visible secondary genital opening in some

102

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. specimens from the Oriental region. In this case the presence of a spermatodactyl may not

coincide with traditional podospermy.

Observations of mating offer behavioral evidence suggesting an intermediate state

even in taxa considered podospermous by definition. This is based on a vertical rather than

the skewed mating position typical of podospermy. Observations of mating in

tocospermous taxa such as suborders Uropodina and Parasitina reveal a similar position

(Evans, 1992). This observation of mating in the Heterozerconidae, follows closely that of

Haemogamasus ambulans (Thorell), including the initial two centrally located positions

described by Young (1968). Mating in Narceoheterozercon ohioensis differs from that in

Haemogamasus ambulans in that the male fails to take the third and final skewed position

for placement of the spermatophore. This suggests that heterozerconid mating, although

podospermous by definition, possesses elements of a transition state between tocospermy

and podospermy.

Further support is found in the fine structure of the spermatozoa which appears to

support the transition between tocospermy and podospermy within the family. Two main

types of spermatozoa have been described in the Mesostigmata, with an intermediate type

found in Celaenopsis badius (C. L. Koch, 1839) (Antennophorina) andMegisthanus

floridanus Banks 1910 (Mesostigmata: Megisthanidae) (Alberti and Klompen, 2001). The

vacuolate type is found in those taxa exhibiting tocospermy. Another type of spermatozoa,

the ribbon type, has been discovered in those exhibiting podospermy (Alberti, 1984).

Spermatozoa in Narceoheterozercon appear to be derived from the vacuolate type (Alberti

pers. comm.), yet podospermous taxa are present in all 4 zoogeographic regions.

Both tocospermy and podospermy occur in the order Mesostigmata. A transition

from tocospermy to podospermy should occur somewhere in this order. Thus far, there

are no documented cases of these two methods occurring together in any related taxa.

103

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. These data on the Heterozerconidae, suggest podospermy and a transition form of mating

occur in Heterozerconina.. The results of this study have suggested an origin for the spermatodactyl in the

Heterozerconidae, which explains its unusual position on the fixed digit. It appears to be

derived from existing structures associated with that digit, including the pilus dentilis. If

this hypothesis is correct, the development of the spermatodactyl on the fixed digit would

suggest that it arose independently from that in the Dermanyssina.

4.5 ACKNOWLEDGMENTS

Thanks to the ODNR for providing permits (#RP-120,260). My sincere

appreciation to the Fulbright Foundation and the Philippine-American Educational

Foundation. Thanks to those who provided specimens: Dr. Deiter Mahsberg, Universitat

Wurzburg; Dr. Gary Mullen, Auburn ; Drs. Petra Sierwald, Dan Summers, Phil Parillo,

Field Museum of Natural History; Dr. Ron Ochoa, National Museum of Natural History;

Dr. Barry OConnor, U. of Michigan; Dr. Gerry Krantz, Oregon St. U.; Dr. Magdelena

Vasquez, Quintana Roo; Dr. Phaibul Naiyanetr, Chulalongkom U.; Dr. Mercedes

Delfinado-Baker, Dr. Leonila Raros and Rufino Garcia, UPLB, Philippines.

4.6 REFERENCES

Alberti, G. 1984. The contribution of comparative spermatology to problems of acarine systematics. In D.A. Griffiths and C.E. Bowman (eds.) Acarology VI. Vol. I. Chichester: Ellis Horwood, pp. 479-489.

Alberti, G. and C. Blaszak, 1995. Further observations on spermatozoa in gamasid mites. In D. Kropczynska, J. Boczek, and A. Tomczyk (eds.) The Acari - Physiological and Ecological Aspects of Acari - Host Relationships. Warszawa: Dabor, pp. 15- 22.

104

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Alberti, G. and L.B. Coons, 1999. Chelicerata Arthropoda. Vol. 8C. In F.W. Harrison and R.F. Foelix (eds.) Microscopic Anatomy o f Invertebrates. New York, NY. pp.515-1265.

Alberti, G. and J. H. Klompen, 2001. Fine structure of unusual spermatazoa and spermiogenesis of the mite, Megisthanus floridanus Banks 1904 (Acari: Gamasida: Antennophorina) Acta Zool. (Stockh.) In press.

Athias-Henriot, C. 1968. L’appareil d’insemination laelapoide (Acariens anactinotriches, Laelapoidea. Premieres observations. Possibility d’emploi a fins taxonomiques. Bull. Sci. Bourg., 25: 175-228.

Domrow, R„ 1956. The family Discozerconidae (Acarina, Mesostigmata) in Australia Proc. Lin. Soc. N.S.W., 81 (2): 192-196.

Evans, G. O., 1992. Principles of Acarology. Wallingford: C.A.B.I. International, 563 pp.

Flechtmann, C H.W. and D.E. Johnston, 1990. Zeterohercon, a new genus of Heterozerconidae (Acari :Mesostigmata) and the description ofZeterohercon amphisbaenae n. sp. from Brasil. Int. J. Acarol., 16: 143-147.

Finnegan, S. 1931. On a new heterozerconid mite parasitic on a snake. Proceedings of the Zoological Society, London, 4: 1349-1357.

Krantz, G. W. 1978. A Manual of Acarology. Ed. 2. Corvallis: Oregon State University Book Stores, 509 pp.

Lawrence, R. F. 1939B. Notes on the habits of the two mites living on South African millipedes. Trans. Roy. Soc. S. Africa., 27: 233-239.

Lee, D. C. 1970. The Rhodacaridae (Acari: Mesostigmata); classification, external morphology and distribution of genera. Rec. S. Aust. Mus., 16: 1-219.

Young, J. H. 1968. The Morphology of Haemogamasus ambulans II. Reproductive system (Acarina: Haemogamasidae). J. Kansas Entomol. Soc. 41: 532-543.

105

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. B

pd cs . & i ; 50nm

Figure 4.1: Discozercon sp. Australia. A. Discozerconidae chelicerae, B. fixed digit, (cs) curled structure, (pd) pilus dentilis.

106

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 4.2: African zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Cote D’Ivoire, B. Tanzania, C. Gabon, D. Central African Republic, E. Madagascar, (cs) curled structure, (pd) pilus dentilis.

107

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. urn

50 u m me

Figure 4.3: Oriental zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. India, B. Thailand, C Thailand, D. Philippines, E. Malaysia, F. Borneo.

108

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 4.4: Neotropical zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Costa Rica, B. Brazil, C. Venezuela, D. Southern Mexico, E. Ecuador.

109

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 4.S: Nearctic zoogeographic region. Heterozerconidae chelicerae and spermatodactyls. A. Narceoheterozercon ohioensis, Ohio, USA. B. Heterozerconidae, Alabama, USA. C. Narceoheterozercon sp., Florida.

110

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 4.6: Narceoheterozercon ohioensis. Male spermatodactyl storage beneath dorsum.

■Y

V \ ' ■ V ■‘ns n £

Figure 4.7: Narceoheterozercon ohioensis. Female secondary genital opening (sgo) and associated ducts.

I ll

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Figure 4.8: Heterozerconidae female, coxa IV. Madagascar, (sp) spermatheca.

112

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. LIST OF REFERENCES

Alberti, G. 1984. The contribution of comparative spermatology to problems of acarine systematics. In D.A. Griffiths and C.E. Bowman (eds.): Acarology VI. Vol. I. Chichester: Ellis Horwood, pp. 479-489.

Alberti, G. and L. B. Coons. 1999. Chelicerata Arthropoda. Volume 8C. New York. NY: John Wiley & Sons, Inc., pp. 515-1265.

Athias-Henriot, C. 1968. L'appareil d’insemination laelapoide (Acariens anactinotriches, Laelapoidea. Premieres observations. Possibility d’emploi a fins taxonomiques. Bull. Sci. Bourg., 25: 175-228.

Athias-Henriot, C. 1975. Nouvelles notes sur les Amblyseiini, 2. Le releve organotaxique de la face dorsal adulte (Gamasides protoadeniques, Phytoseiidae). Acarologia, 17: 20-29.

Baneijee, B. 1967. Seasonal changes in the distribution of the millipede Cylindroiulus punctatus (Leach) in decaying logs and soil. J. Animal Ecol., 36: 171-177.

Barlow, C.A. I960. Distributional and seasonal activity in three species of diplopods. Ark. Neerlandaises Zool., 13: 108-133.

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Reproduced with permission of the copyright owner. Further reproduction prohibited without permission. Berlese, A. 1888. Acari Austro-American quos collegit Aloysius Balzan. Bull. Soc. It., 20: 171-222 (pi. XI, fig. 1).

Bhattacharyya, S. L. 1962. Laboratory studies on the feeding habits and life cycles of soil inhabiting mites. Pedobiologia, 1:291-298.

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