Taxonomy of Acrobasis Larvae and Pupae in Eastern North America (Lepîdoptera: Pyralidae)
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4 We. «^'«*^ 3 Taxonomy of Acrobasis Larvae and Pupae in Eastern North America (Lepîdoptera: Pyralidae) Technical Bulletin No. 1457 Agricultural Research Service UNITED STAT^JS DEPARTMENT OF AGRICULTURE in cooperation with North Carolina Agricultural Experiment Station /, ' Taxonomy of Acrohasis Larvae and Pupae in Eastern North America (Lepidoptera: Pyralidae) By H. H. Neunzig Technical Bulletin No. 1457 Agricultural Research Service UNITED STATES DEPARTMENT OF AGRICULTURE in cooperation with North Carolina Agricultural Experiment Station Washington, D.C. Issued December 1972 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $1.25 Stock Number 0100-2471 Acknowledgments This study was conducted under Agricultural Research Service Grant No. 12-14-100-9150(33). E. L. Todd and D. M. Weisman of the Systematic Entomology Laboratory, Agricultural Research Service, made available for study the collection of Acrobasis adults and immatures at the U.S. National Museum of Natural History. Additional Acrobasis larvae and pupae from Florida and Wisconsin were provided by D. H. Habeck of the University of Florida. I am grateful for the assistance of Betty W. Robbins of North Carolina State University. She reared, preserved, and measured immatures, mounted most of the associated adults, made genitalic dissections, and aided in numerous other ways in the study. A. L. Kyles, E. J. Venuto, T. R. Weaver, and J. D. Wellborn, all cf North Carolina State University, assisted in collecting and rearing. The parasites associated with Acrobasis larvae and pupae that were collected during the study were identified by the following specialists of the Systematic Entomology Laboratory : B. D. Burks, R. W. Carlson, P. M. Marsh, C. W. Sabrosky, and L. M. Walkley. I also thank J. R. Baker of North Carolina State University for preparing figures 158, 159, 161-163, 166, 167, and 170-186. Ü1 Contents Page Materials and methods 2 Key to last-stage larvae ° Key to pupae Acrobasis minimella Ragonot ^^ Acrobasis vaccinii Riley ^^ Acrobasis indigenella (Zeller) ^° Acrobasis caryae Grote ^^ Acrobasis nuxvorella Neunzig 2° Acrobasis elyi Neunzig ^^ Acrobasis evanescentella Dyar ^' Acrobasis angusella Grote Acrobasis demotella Grote ^^ Acrobasis stigmella Dyar ^^ Acrobasis exsulella (Zeller) ^" Acrobasis feltella Dyar ^^ Acrobasis juglandis (LeBaron) 5' Acrobasis caryalbella Ely ^^ Acrobasis kearfottella Dyar "' Acrobasis caryivorella Ragonot '^ Acrobasis sylviella Ely "^ Acrobasis ostryella Ely "^ Acrobasis secundella Ely °^ Acrobasis coryliella Dyar °^ Acrobasis carpinivorella Neunzig °^ Acrobasis cunulae Dyar and Heinrich ^2 Acrobasis betulella Hülst ^^ Acrobasis rubrifasciella Packard 1^" Acrobasis comptoniella Hülst ^^* Acro6asis myricella Barnes and McDunnough 112 Discussion 11° Literature cited ^25 IV Taxonomy of Acrobasis Larvae and Pupae in Eastern North America (Lepidoptera: Pyralidae) By H. H. NEUNZIG, Department of Entomology, North Carolina State University Acrobasis is one of the largest genera within the subfamily Phycitinae of the Pyralidae. Most of the known species are either Nearctic or Palaearctic in distribution, with the greatest number concentrated in eastern North America. The adults are small and cryptically colored. The larvae are secretive, usually living in parts of the host plant or in frass tubes on the host. Approximately one-half of the species in eastern North America feed as larvae on trees of the genus Carya of the family Juglandaceae, and the remaining species are associated with the genus Juglans of the Juglandaceae or with members of the Myricaceae, Betulaceae, Fagaceae, Rosaceae, or Ericaceae. Several eastern North American species are of economic impor- ta,nce, including the cranberry fruitworm (Acrobasis vaccinii Riley), the pecan nut casebearer (A, nuxvorella Neunzig), the pecan leaf casebearer (A. juglandis (LeBaron) ), the leaf crumpler (A. indigenella (Zeller)), and the birch tubemaker (A. betulella Hülst). As presently constituted, Acrobasis is not a rigidly defined genus. On the basis of adult morphology, species complexes or groups are evident. For example, with both American and Euro- pean species the primaries are smooth in some, but others possess a transverse median ridge of raised scales. Also, with males the apical process of the gnathos is simple in European species but either simple or trifúrcate in American species. Within the species groups, however, the adults of some species are very similar in appearance, and several occurring in North America can be identified only with difficulty (Forbes 1923; Hein- rich 1956).^ Not only is the color pattern of the primaries and body similar, but the male and female genitalia of most species are of limited diagnostic value. Many of these similar species also occur ' The year in italic after the authors' names indicates the reference in Literature Cited, p. 125. 2 TECHNICAL BULLETIN 1457, U.S. DEPT. OF AGRICULTURE on the same or closely related hosts as larvae. A number of the species listed by Heinrich in his revision v^ere included on a tenta- tive basis inasmuch as he could not, by examining the adults, es- tablish with certainty whether he was dealing with discrete taxa. Literature on the appearance of the larvae and pupae of Aero- basis is mostly of limited value because of inadequate descriptions and drawings or photographs with insufficient detail (Saunders 1870; Grote 1881a; Riley 188J^, 1885; Beutenmuller 1889, 1890; Hülst 1890; Ragonot 1893; Felt 1909; Herrick 1909; Gill 1917a, 1917b, 1925; Scammel 1917; Weiss 1921; Forbes 1923; Bilsing 1927; Franklin 1928,19JÍ8; Quaintance and Siegler 1931; Daviault 1937; Moznette et al. 19W; Craighead 1950; Peterson 1956; Phil- lips et al. 196Í; Osburn et al. 1966; Balduf 1966). The only de- tailed comparative studies of larvae have been reported by Hinten {19Jf3) andHasenfuss {I960), B.mion ir^^i^á Acrohasis juglandis and A. nuxvorella (caryae), Hasenfuss did not provide informa- tion on American species but included solely European species of the genus. Mosher {1916) in her study of Acrobasis {Mineóla) indigenella and A. rubrifasciella Packard gave limited but useful data on pupal morphology within the genus. There is considerable information available on the biology of the immature stages of Acrobasis species. Most of it, however, applies to species of economic importance. Information on the biology of many of the noneconomically important species, partic- ularly those in North America, is very fragmentary. The purpose of this bulletin is to provide keys and descriptions for the last-stage larvae and pupae of most of the Acrobasis spe- cies in eastern North America. Data are also given on the host plants, distribution, biology, and associated parasites of these spe- cies. In addition, the status of several nominal species is clarified, and affinities within the genus, as suggested by the morphology and biology of the immature stages, are discussed. Materials and Methods Most of the larvae and pupae studied were obtained in collecting trips from 1966 to 1970 in North Carolina, New England, and Florida. Usually last-stage larvae were collected. About one-third were preserved and the remainder were reared on a part of the host plant to obtain pupae and associated adults. Preserved larvae and pupae were initially fixed in KAAD (a mixture of kerosene, alcohol, acetic acid, and dioxane) and later transferred to 80-per- cent alcohol. TAXONOMY OF ACROBASIS LARVAE AND PUPAE 3 Larvae were reared in 1-pint paper enclosures, which contained 2 to 3 cm. of moist sand. The sand was necessary to keep the plant material palatable for several days and also to provide a medium for those species that normally pupate in the soil. Following pupa- tion the insects were transferred to small transparent plastic con- tainers so that adult emergence could be readily detected, and the insect was killed shortly after eclosión. Some larvae and pupae from the U.S. National Museum of Nat- ural History were also studied, but only immatures that could be definitely identified by reference to reared adults were included. Most of the biological data were obtained when the last-stage larvae were collected in the field. However, several separate field trips were also taken to establish the time of occurrence and behavior of the early-stage larvae, time of pupation, and other phenomena. Genitalia slides were prepared of representatives of most reared series, and specimens were identified by referring to Heinrich {1956) and by studying the adults in the National Museum collec- tion. Some reared adults differed from all species previously de- scribed, and one nominal species was established to be a complex of several species. These new species have recently been named (Neunzig 1970) and are included in this bulletin. Numerous hymenopterous and dipterous parasites were reared from the Acrobasis larvae and pupae and these were sent to spe- cialists at the National Museum for identification. The names of these reared parasites are included here along with the names of Acrobasis parasites previously recorded in the literature. It was difficult to identify in the literature some of the Acrobasis species parasitized, particularly such species as Acrobasis caryae and A, nuxvorella, whose identities have been confused until recently. With these insects, parasites were assigned wherever possible on the basis of geographical distribution of the Acrobasis species and insect-plant relationships. Descriptions of larvae