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Doctoral Dissertations 1896 - February 2014
1-1-1972
Observations on the biology and control of Glyptotendipes lobiferus (Say) (Diptera: Chironomidae).
Winston Hayden Lavallee University of Massachusetts Amherst
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Recommended Citation Lavallee, Winston Hayden, "Observations on the biology and control of Glyptotendipes lobiferus (Say) (Diptera: Chironomidae)." (1972). Doctoral Dissertations 1896 - February 2014. 5612. https://scholarworks.umass.edu/dissertations_1/5612
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OBSERVATIONS ON THE BIOLOGY AND CONTROL
OF
GLYPTOTENDIPES LOBIFERUS (SAY) (DIPTERA: CHIRONOMIDAE)
A dissertation presented By
WINSTON HAYDEN LAVALLEE
Submitted to the Graduate School of the University of Massachusetts in partial fulfillment of the requirements for the degree of
DOCTOR OF PHILOSOPHY
April 1972
Major Subject: Entomology OBSERVATIONS ON THE BIOLOGY ANT) CONTROL
OF
GLYPTOTENDTPES LOBIFERUS (SAY) (DIPTERA: CHIRONOMIDAE)
A Dissertation
By
. WINSTON HAYDEN LAVALLEE
Approved as to style and content by:
,: /f- (Chairman of Committee;
Anril 1972
(Month) (Year) ACKNOWLEDGEMENTS
In appreciation for the helpful guidance and assistance in pre¬ paring this dissertation, the following acknowledgements are made to:
Dr. Frank R. Shaw, Chairman of the Thesis Committee, for
constant encouragement and patience throughout this study,
his many thoughtful suggestions and his unselfish sharing
of time and resources, particularly after his retirement
while in an emeritus status.
i Dr. T. Michael Peters, Thesis Committee member, for valuable
suggestions in preparing the manuscript and in obtaining sup¬
plies and equipment used in the study.
Dr. William G. Nutting, Thesis Committee member, for sound
suggestions in writing and organizing the manuscript.
Dr. Richard A. Damon, member. Department of Animal and
Veterinary Science, for statistical advice, patient
explanation of selected statistical methods and helpful
orientation to use of the computer.
Dr. Jonn Ii. Lilly, member, Entomology Department, for
encouraging this study initially, providing advice and
test materials and for reviewing graphs and tables and
suggesting valuable improvements therein.
• • 11 Dr. Hugo Jamnback, Entomologist, New York State Science
Service, State University of New York - Albany, for
identification of the midge species investigated.
Holyoke Water Power Co. for supporting this study in part and cooperating to the utmost in all phases of the investi gation. Particular appreciation is expressed to
Mr. Carl G. Schmidt, Manager of Operations and the late
Mr. Robert H. Walker, Vice President.
Brown Co. for cooperation in all phases of the study, particularly in those pertaining to midge control.
Special thanks is due Mr. David L. Tomlinson and
Mr. Charles L. Kirkpatrick.
Holyoke Community College for providing space in which to complete certain tests and for the loan of equipment vital to the study.
Dr. William A. Hutchinson for valuable comments on pre¬ paring the manuscript.
Mr. Carl W. 3uschner for photography assistance.
Mr. Norman P. De Bastiani for providing materials neces¬ sary for the preparation of manuscript figures.
. nichard M. Sparrow xor helpful suggestions regarding the duplication of the manuscript.
• • • m My many colleagues, students and friends at Holyoke
Community College who encouraged this study and whose thoughtfulness and cooperation made its completion possible.
My family, particularly my wife Margaret, who, having lived through the extended period necessary for com¬ pletion of the thesis, deserve special thanks.
iv TABLE OF CONTENTS
Page I. INTRODUCTION . 1
XI. REVIEW OF LITERATURE. 4
III. OBJECTIVES. 16
IV. METHODS. 17
A. Description of Study Areas .
B. Sampling Procedures for Adults . • •
C. Sampling Procedures for Larvae. 31
D. Sampling Procedures for Eggs. 3 5
E. Miscellaneous Sampling Procedures ...... 3 6
F. Midge Control Procedures - Laboratory . . .. 3 9
G. Midge Control Procedures - Field . 46
V. RESULTS AND DISCUSSION. 5 2
A. Survey of Adults. 5 2
B. Survey and Control of Eggs. 75
1. Effects of dessication on eggs - field. 77
2. Effects of dessication on eggs - laboratory. ... 77
3. Control of eggs by heat treatment. 79
4. Control of eggs by malathion treatment .. 79
C. Survey and Control of Larvae. 79
1. Field studies.
2. Lou temperature effects on survival of larvae - laboratory. 35
D. Laboratory Insecticide Studies . 37
1- %gs. 87
V Page 2. Larvae. 91
3. Adults. 9 8
E. Field Insecticide Studies on Adults. 9 8
1. Field control. 9 8
2. Longevity of malathion. 105
F. Midge Biology and Behavior . Ill
1. Description of emergence.Ill
2. Description of swarming.116
3. Description of mating.121
4. Description of oviposit!on.125
5. Midge larvae studies with acetate samplers .... 129
VI. SUMMARY AND CONCLUSIONS.137
VII. LITERATURE CITED.142
VIII. APPENDIX.149
ACKNOWLEDGEMENTS. ±±
vi LIST OF TABLES
Table Page
1. Adult midges collected in 2 "black light traps during the summer of 19^9. 5 4
2. Adult midges collected in 3 "black light traps during the summer of 1970... 60
3. Mean number of adult midges collected on six inch square adhesive traps located on mill ■window screens and on ice fenders above canal water surface. 65
4. Adhesive trap data. Numbers of midge adults trapped near canal water surface per unit time during the summer of 1970. 6 6
5. Adhesive trap data. Numbers of midge adults trapped on mill window screens per unit time during the summer of 1970... . 71
6. Number of egg masses found per 6 inch by 6 inch surface, Holyoke Study Area, August 17, 1970 . 76
7. Hatching of midge egg masses after 14 hours of exposure to drying on canal walls and on ice fender surfaces ... 73
8. Effects of brush burner and malathion treatments on the hatching of midge eggs in the Holyoke Study Area. 8 0
9. Numbers of midge larvae per square foot of sampled surface in the Holyoke Study Area during periodic drainages, 1967-71. 33
10. Effects of 22 hours of low temperature on the sur¬ vival of 4th instar larvae in the laboratory. 3 6
11. Effects of 1 ppm Abate, malathion and Naled on the hatching of midge eggs at the end of 51.5 hours exposure ...... 88
12. Effects of 1, 10 and 1000 ppm Rabon on the hatching of midge eggs at the end of 43 hours of exposure. 9 q
13. Effects of 1 ppm Abate, malathion and Naled on 1st instar midge larvae at the end of 4 hours of exposure in the laboratory. Q 9
• • vu Page Ik. Effects of 10 ppm Abate,, malathion and Naled on 1st instar midge larvae after various time exposures ..... 9 4
15. Effects of 1000 ppm Abate, malathion and Naled on field collected 2nd and 3rd instar midge larvae in tubes on acetate samplers at the end of 2 hours after treatment. 9 6 lo. Effects on adult midges of 10 hours of exposure to Rabon or malathion (0.1$) in small aluminum cages immediately after treated cages had drip-dried . 99
17. Effects on adult midges of 10 hours of exposure to Rabon and malathion (0.1$) in small aluminum cages two days after treated cages had drip-dried. ... 10 0
18. Effects of malathion applied at a rate of 1.4 lbs. actual per 100 gallons of mixed spray on the numbers of midge adults resting on 32 inch by 32 inch mill window screens in the Holyoke Study Area.103
19. Effects of Rabon applied at a rate of 1.0 lbs actual per 100 gallons of mixed spray on the numbers of midge adults resting on 32 inch by 32 inch mill window screens in the Holyoke Study Area.104
20. Longevity of malathion on brick surfaces. Recorded as numbers of midges resting on brick square foot surfaces <■.106
21. Longevity of malathion on glass pane surfaces. Re¬ corded as numbers of midges resting on glass pane surfaces (131.6 inch^) . 108
22. Number of adults emerging at various time intervals as determined by catches in emergence traps, 1970 and 1971..
23. Time of the first emergence of midge adults on six separate days in the summer of 1970 .. 113
24. Length of time in seconds required for adult to free itself from the pupal skin and become airborne. Data obtained on three separate days in the summer of 1970 . 114
25. Number of adult midges which emerged per minute in artificial light or in darkness as determined by catches in emergence traps. I97O and 1971 . . . .
• • • vxn Page Physical factors recorded at time of organized 117 swarming of midges ......
27. Samples taken in the summer of 1970 of small, organized midge swarms at dusk •••••••••• 120
28. Mating of midges. Length of time of copulation and height above the ground at separation Ox pairs • • 122
Mating data, egg laying and hatching data and 29. 124 longevity of selected midge pairs, 1971 .
30. Time required from the beginning of one female oviposition attitude to the post-oviposition flight in the field. 127
31. Egg mass sizes at the time of egg extrusion by ohe female, maximum size 01 egg mass alter absorbing water and minimum length of time required to reach maximum size.. 128
32. Numbers of selected aquatic animals adhering to acetate-faced wood samplers at the one foot depth in canals during the summer of 1970 . 132
33. Numbers of selected aquatic animals adhering to acetate-faced wood samplers at the one foot depth in canals during the summer of 1971. 185
34. Measurement of some physical and chemical variables in canal water at the South Hadley Falls study area (Overflow) during 1970 .Appendix
35. Measurement of some physical and chemical variables in canal water at the Holyoke study area (Valley Paper Co. ice fender) during 1970 .Appendix
ix LIST OF FIGURES
Figure Page
1. Holyoke and South Hadley Falls study areas 18
2. Holyoke study area. Shows location of: Adult Midge Adhesive Traps, Blacklight Traps, Adult Resting Count Areas...19
3. South Hadley Falls study area. Holyoke study area.2 0
4. Black light used in adult midge surveys located north of the Valley Paper Co. mill.2 3
5. Emergence trap used to collect adult midges shown in position near the ice fender of the Valley Paper Co. . . . 26
o. Adhesive traps located on mill window screening and near the canal water surface in the Holyoke study area .... 28
7. Square foot samplers with acetate facing used to survey selected aquatic animals in canal waters . 32
8. View of drained canal in the Holyoke study area adjacent to the Brown Co. office Building..
9. Aspirator and collecting vessel used to collect adult midges for laboratory insecticide treatments. Aluminum screen cage with collecting vessel attached used to enclose adult midges during laboratory insecti¬ cide treatment..
10. Brick wall and glass pane surfaces to which malathion was applied in studies of length of time agent remained effective.... . 49 li. Truck mounted power sprayer used to apply malathion to walls of drained canals. Malathion being applied to ice fender surface by the author . . 51
12. Number of midges collected during the summer of 1969 at the Conn. River and Valley Paper Co. black light trap station. . 53
13. Number of midges collected during the summer of 1970 at the Valley Paper Co. black light trap station. . 57
x Page 14. Number of midges collected during the summer of 1970 at the Brown Co. black light trap station. 5 8
15. Number of midges collected during the summer of 1970 at the Conn. River black light trap station . 59
16. Numbers of adult midges collected during the summer of 1970 in six inch square adhesive traps located on mill window screens or attached to ice fenders near canal water surface. 6 4
17. Mean number of midge larvae found per square foot in the Holyoke study area during periodic canal drainages . . 84
18. Effects of 1 ppm Abate, malathion and Naled on the hatching of midge eggs at the end of 51*5 hours of exposure. 89
19. Effects of 1 ppm Abate, malathion and Naled on the survival of first instar midge larvae at the end of 4 hours of exposure. 9 3
20. Effects of 10 ppm Abate, malathion and Naled on the survival of first instar midge larvae at the end of various indicated time exposures . 95
21. Effects of 1000 ppm Abate, malathion and Naled on / the survival of second and third instar midge larvae in tubes on acetate samplers at the end of 2 hours of exposure. 97
22. Effects of Rabon and malathion on adult midges at a concentration of 0.1$ when applied to the screening of small aluminum cages. 101
23. Regression analysis of the effectiveness of malathion on brick surfaces on seven days following applica¬ tion .‘.10 7
24. Regression analysis of the effectiveness of malathion on glass surfaces on seven days following applica- tion.109
xi I. INTRODUCTION
The group of insects known as the chironomid midges (Chironomidae
= Tendipedidae'1') Order Diptera, are usually rather inconspicuous and
innocuous. Although they do not attack man or animals,, mass emergences
may create an intolerable nuisance when they alight on the body or
enter homes, industries and restaurants. Many other aquatic insects
such as chaoborid midges, mayflies, and caddisflies may become troub¬
lesome on occasion, but the chironomids are one of the most frequently
cited nuisance organisms.
Because chironomids are found in many different habitats such as
eutrophic lakes, polluted streams and estuaries and include so many
different species, the development of effective control methods must be
suited to the biology of each species. Methods employed against mos¬
quitos frequently have failed or have not been practical for economic
reasons. Often, the larval breeding areas are bodies of water which
serve as sources of drinking water or for an industrial use. Radical
changes of the physical environment or the use of insecticides in such waters might create a hazard to humans and other organisms or render
the water supply useless for industrial processes through chemical con¬
tamination.
Summer nuisance outbreaks of flying insects in the City of Holyoke
have been especially intense in certain years, particularly in those
ine nomenclature used herein is based on the work of Sublette and Sub¬ lette (1965). The synonomy of Glyptotendipes lobiferus (Sav) mav be found in the Appendix.
1 2
areas 'bordering the Holyoke Canal system. This canal system in partic¬ ular, and the adjacent river as well, serves as a breeding area for the
immature stages of many aquatic insects. The canals total miles in
length, vary in width from 80 to 140 feet, and in depth from 6 to 30 feet. Water enters the system from the Connecticut River through a main gate just above the Holyoke Dam and moves through three levels, finally re-entering the river at various points through 5 overflow sta¬ tions. Total capability of the system is 10,000 cubic feet per second, but it is normally operated below this rating.
Although mayflies, caddisflies and many dipterous insects are known to be fairly numerous in the summer season, the midge, Glyptoten- dipes lobiferus (Say)2 appears to be the most significant nuisance spe¬ cies. Huge numbers of this species may emerge rather suddenly during hot weather, at times making human passage between buildings and near the canals comfortable only by holding a handkerchief over the mouth and nose. Paper industries located near the canals are severely ham¬ pered in their operations due to the inevitable entrance of the midges into their buildings. Wot only do workers complain of the mosquito- like midges alignting on their oodies, but when midges fall into pacer—
P1ocessing machines, great quantities of quality paper are down-graded by the brown stain of crushed insect bodies.
^or a number of years, control of the midge has been attempted through screening of buildings and insecticide treatment of the canal
Specimens were kindly identified by Dr. Hugo Jamnback, Entomologist Hew York State Science Service, State University of New York Albany New York. 9 “ J7 3
vails during the summer drainage vhen canal repairs vere oeing made.
These procedures have been employed vith virtually no reference to midge biology and seasonal distribution, and vith no quantitative assessment of the value of the insecticide treatments* ocieeniug a^d closure of buildings is difficult to enforce in hot veather because of inadequate ventilation for vorkers. Necessary loading and traffic operations in and around buildings compound the problem oi building closure. Thus, reduction of the midge nuisance has been limited and insecticidal control effects have been questionable.
The purpose of this study vas to investigate the biology and seasonal distribution of the midge, G. lobiferus, and to develop methods of control. II. REVIEW OF LITERATURE
A. Biology and Ecology of the Chironomidae.
The work of Brundin (1949), Thieneman (1954), Mundie (1957), Curry
(1962), Grodhaus (1963a) and Oliver (l97l) give general and detailed
information on the biology of chironomids as well as extensive bibli¬
ographies. To date, over 500C species have been described world-wide
(Oliver,, 1971)* North American chironomids total nearly 5C0 described
species (Grodhaus, 1963a). Identification is difficult because the
taxonomy of the group has been unsettled. No single work covers all
North American species, but the following are useful and reflect cur¬
rent taxonomy: Townes (1945), Johannsen and Townes (1952), adults;
Roback (1957)> Curry ^1902) and Mason (1968), immature stages. Wirth
and Stone (1956) have keys to all genera and stages except eggs.
Morrow, et al (1968) review the literature on eggs and include keys to
California species together with a bibliography.
j-i^e midge liie cycle is typically holometabolous. Eggs are gener¬
ally laid in a gelatinous, transparent or translucent packet or string wnich expands In water to several times its original size. Single eggs
or masses Oj. approximately 1000 with special suspensory stalks and
anchor cords may be deposited. The pattern of egg deposition within
the gelatin may be quite characteristic for subgroups of chironomids
(Oliver, 1971). These eggs are very susceptible to dessication.
Fellton (19^0) detected no hatching of eggs exposed for seven hours on a dry surface. The embryonic development which takes place during the short post-oviposition period is followed by immediate hatching
4 5
(Grodhaus, 1963a).
Larvae are distinguished "by the sclerotized head capsule, 12 "body segments and prolegs on the first and last abdominal segments
(Grodhaus, 1963a.). Some larvae are red due to the presence Oi hemo¬ globin "within their bodies (Eiver, 1942; Walsh, 1947a); hence the com¬ mon bloodworm for these forms. This feature is not uniform among all species (Walshe, 195l)> uor does any particular larva always possess the red pigment in all instars for these species (see Hilsenhoff,
1966). The larval period consists of four instars. It is both the longest period in the life cycle and the most resistant to winter con¬ ditions, particularly the fourth instar (Grodhaus, 1963a; Hilsenhoff,
1966). Sadler (1935) reported that low temperatures in the larval environment arrested development but he did not consider the length of the photoperiod. Engl^mann and Shappirio (1965) found that "short" days (8 hours light and l6 hours dark) initiated diapause and that
"long" days (l6 hours light and 8 hours dark) broke diapause, while temperature suitable for development during diapause did not stimulate growth.
The larvae of midges inhabit many different freshwater and marine
environments. Even terrestrial larvae (Camptocladius sp.) have been found (Lawrence, 195*0* The most usual habitats are relatively slow- moving waters where the larvae are found in the bottom sediments
(Lindeman, 1942, Oliver, 1971). Depending on the species, the larvae
may be burrowing, clinging, crawling or tube-dwelling in behavior.
Adaptations of behavior to diverse substrata are found and locomotion 6
by swimming is well-developed. Most larvae restrict themselves to either the upper few inches of a substrate or contiguous to it
(Grodhaus, 1963a; Oliver, 197l). 1)213 ls particularly true for tube- dwellers which construct their tubes from salivary secretions and debris from the substrate. Aquatic plants may be penetrated by larvae and used both for food and habitation (Burtt, 19^0; Berg, 19^9, 1950)•
The food of larvae is gathered by filter-feeding or by browsing.
Particulate debris and phytoplankton are common sources of food. Larger
submerged plants may be penetrated or defoliated by herbivores; pre¬
daceous larvae are known to feed on other chironomids, other insects,
small crustaceans and small annelids (Grodhaus, 1903a).
Respiratory modifications permit a high tolerance for waters low
in oxygen. Oxygen is absorbed through the cuticle. Some larvae also
have tubular extensions of the posterior segments which increase sur¬
face area thus extending the respiratory surface (Grodhaus, 1963a).
Many larvae contain hemoglobin which may increase oxygen utilization
under certain conditions (Eiver, 1942). The work of Walshe (1947b) on
Tanytarsus sp. disputes this, however, and Buck (1953) agrees. Tube-
dwellers undulate the body within the tube creating water currents
which theoretically have the effect of increasing body contact with
oxygen. This activity, however, may be associated more with food
gathering as is indicated by the studies of Leathers (1922), Burtt
(1940) and Berg (l950)»
The pupa resembles some other members of the Nematocera in that
the head and thorax are fused and enlarged. Respiratory organs may be present on the thorax and the posterior abdomen may bear fin-like or paddle-type processes (Grodhaus, 1963a). The short pupal stage shows typical adult formation and gonad maturation. The pupae of the sub¬ family Chironominae are sedentary and undergo development within a tube-like case prior to rising to the water surface in preparation for emergene e (Oliver, 1971) •
The adults are rather fragile insects, many of which superficially resembling mosquitos in form and size. The antennae have no fewer than
6 distinct segments and are, in males, usually plumose. The phantom midges (Chaoboridae) have conspicuous hairs on the wing veins, but not on the membranous cells; the chironomids have hairs clothing the cells as well as the veins of the wings. The biting midges (Heleidae = Cer- atopogonidae) have wings similar to chironomids, but have piercing¬ sucking mouthparts which are lacking in the latter. Most chironomids also have a longitudinal ridge or groove on the postnotum. Body color may be yellow, brown, green, grey or black (Grodhaus, 1963a).
The four main functions of the adult midges (swarming, copulation, dispersal, and oviposit!on) may be achieved within a few days or, at most, several weeks after emergence (Grodhaus, 1963a), (Fischer, 1969),
Oliver (1971). According to Downes (1969), swarming brings the sexes together from a dispersed population and is highly useful to ensure mating by short-lived insects such as the Chironomidae. Swarms are maintained by the midges’ exploitation of swarm markers (tree-lines, etc.) which reduce swarm dispersal (Downes, 1969). Nielsen and Grieve
(1950) believe that swarming serves other than just a mating function 8
since they observed few matings in swarms.
The time interval for development of each stage is highly variable
depending on the species, ranging from about one month to two years.
Sadler (1935) investigated time intervals for Tendipes tentans Fab.
development in the laboratory and found the following;
Ego¬ 3 - 17s days ist Larval Instar 5- 9 days 2nd Larval Instar 6 - 8 days 3rd Larval Instar 6- 10 days 4th Larval Instar 4-21 days Pupa 3 clays Time from emergence to oviposition 1 - 3 days Longevity of female 3i days Longevity of male 5 days
At room temperature this species took approximately 26 to 52 days to
develop from hatching to adult emergence.
Adult emergence peaks are known to occur in the spring (Fischer,
19£>9 )> (Thut, 1969) when an overwintering population of larvae may
transform to pupae and emerge as adults in response to warming water
temperatures. Summer emergence peaks may result from temperature and
lignc intensity changes with considerable variation between these exo¬
genous factors depending on geographical location and whether the spe¬
cies in question is bivoltine or multivoltine (Oliver, 1971),
Fiommex and Rauch (1971) report that maximum daily emergence of
adults of Picrotendipes californicus (Johannsen) occurs in a half hour period commencing shortly after sunset at 8 P.M. during July and August.
Counts of pupae were extremely low after the period of maximum emer¬
gence. Darby (1962) found that total numbers of various midge species
collected in a lignt trap declined from 8:30 P.M. to 1:30 A.M, in 9
August. Summer habits of adult Glyptotendipes paripes (Eduards) were
studied by Nielsen (1959, 19&2a) who found that emergence occurred dur¬ ing a one hour period, about an hour after sunset. Winds carried adults to shore where they remained close to the water until sunset of the next day at which time swarming and copulation took place. Copu¬ lation occurred both in flight and after adults had alighted. Sperm transfer was accomplished by a spermatopkore. Female midges, 30 to 40 hours after emergence, laid eggs and then died during the night or the next day. Young females mated and oviposited the following evening.
Fryer (1959) detected a lunar rhythm of emergence 3 to 5 days after a full moon in the African midge, Chironomus brevibucca (Kieff.).
Chironomids are attracted to lights at night, but in the daytime they seek shaded areas such as in or on man-made structures and vegetation.
Weather conditions and species differences may modify this typical adult behavior. (Nielsen (1962a) suggests that day-resting midges move into contiguous vegetation or fly repeatedly for brief periods to avoid heat. Despite this activity, he found that these adults never moved far from the areas initially selected each day.
Nuisance outbreaks of adults have often been correlated with high organic loads in waters inhabited by the immature stages. Eutrophica¬ tion is generally a favorable condition for phytoplankton and rooted plant development because of an abundance of nutrients such as nitro¬ gen and phosphorus. In such an environment midge larvae obtain both food and shelter. Euorophic conditions may result in sharp fluctuations of the oxygen concentration, particularly at the mud-water interface. 10
thereby limiting or excluding some predators or competitors of the lar¬ vae (Grodhaus, 1963a). Burrill (1913) and Hilsenhoff (1966, 19^7) re¬ ported large numbers of Tendipes plumosus (Linn.) from the eutrophic
Lake Winnebago in Wisconsin. Johnson and Munger (1930) found the same species in high numbers in Lake Pepin, an expansion of the Mississippi
River, which received sewage. Fell ton (19^-0, 19*1-1) found that nutrient- rich artificial lakes at the World's Pair, Flushing, New York were breeding Glytotendipes spp. Gerry (1951* 195*0 examined sludge beds in a polluted Massachusetts tidal stream (Merrimack River) and found
Glyptotendipes lobiferus (Say). Jamnback (195*0 studied Moriches Bay,
Long Island, New York which yielded massive numbers of Tendipes attenn- atus (Walker) when the salinity decreased and duck farm waste into the bay increased. Conditions in eutrophic lakes in Florida, where
Glypotendipes paripes (Edwards) bred, were described by Lieux and
Mulrennan (1956). Tidal creeks, spreading areas for ground water supply recharge, flood control channels and sewage oxidation ponds in Cali¬ fornia have been mentioned as sources of adults in the papers of Usinger and Kellen (1955)* Grant (i960), Anderson and Ingram (i960), McFarland, et al (1962), and Grodhaus (1963b).
Considering these diverse adaptations and habitats, it is clear that, as a group, fresh-water chironomids are not limited to any dis¬ tinctive water sources. Indeed, either new water impoundments or the re-establishment of water habitats after drainage may result in rapid colonization (Paterson and Fernando, 1969). Brumbaugh et al (1969) sug¬ gests that midge development in new bodies of water apparently diminish 11
as the ecosystem ages. Anderson, et ad (1964) found that 10 times as many midges developed in acrolein algicide-treated water-spreading
■basins as in adjacent check basins. These evidences indicate that factors influencing rapid population increase are poorly understood, and that certain broad spectrum toxicants may affect population dynam¬ ics in such a way as to create more problems than are solved.
Most female chironomids produce large numbers of eggs. Morrow, et ad (1968) reported Chrionomus stigmaterus Say as having a mean num¬ ber of 1319 eggs per female (based on lo masses). Sturgess and
Goulding (1969) recorded 1500-2000 eggs per mass for G. barbipes
(Staeger). Various environmental factors reduce larval survival in¬ cluding parasitism by bacteria, fungi, protozoa, nematodes and trema- todes, and predation by leeches (Hilsenhoff 1963), fish, insects, snails, and other natural controls such as disease agents (Hunter 1969) and competition for food. Chapman and Ecke (1969) reported mermithid nematode parasitism as contributing to a decline in Tanytarsus sp. populations, and also a cause of sexual abberation in parasitized adults. The effects of other environmental factors are in need of clarification.
B. The Mature of Chironomid Nuisance.
The effects of midge nuisance on man are of concern only when there are mass emergences and flights of adults (Bonnel and Mote, 19)4.1).
Dense dawn and dusk swarming flights may restrict human recreation or sporting activities out of doors and may reduce the visibility of auto drivers. Adults are drawn to lights after dark and will enter homes 12
and eating establishments radily. Industrial establishments may be invaded and annoy "workers or ruin industrial products (Grodhaus, 1963b).
During the day,, great numbers of resting midges are unsightly; they
■will often fly if disturbed. Under such conditions, outside painting
(Grant, i960) or finishing operations (Bonnell and Mote, 19^2), are virtually impossible. Midge corpses and unattractive stains from body exudates may accumulate. Predatory spiders and their webs become com¬ mon.
Direct effects on man's health have been reported. Weil (19^-0) and Lewis (1956) point out the possibility of chironomid body frag¬ ments causing allergic reactions when inhaled. Contradictory evidence exists on the question of mechanical disease transmission by midges from polluted waters (Steinhaus and Brinley, 1957)> (Lysenko, 1957).
C. Control of the Chironomidae.
The control of chironomids has often been met with either limited effectiveness or outright failure. Although chemical control by lar- vicides has received the most emphasis, physical and biological control methods have been employed. Reduction of water sources on a permanent or temporary basis is an obvious control measure. Kimball (1968) obtained control by fluctuating water in impoundments so that a 7 day drying period occurred every 30 days. Usually the water source cannot be so easily manipulated, however. deMeillon and Gray (1937) pumped sea water into a small South African lake to increase salinity and thus reduced midge populations. Tidal action destroyed midge larvae in estuarine creeks studied by Grant (i960). Brown (1933) used covers to 13
exclude midges from small water-storage reservoirs.
Biological control of larvae by fish predators has been attempted
Bay and Anderson (1965) Mezger (1967) and Kimball (1968) reported gooa
control with carp and goldfish, so long as the area searched by the
fish was not extensive. Control efficiency drops drastically when the
area is increased, as in large lakes. In xhe laboratory °- Cc'°“
(1962) the little aeneus catfish, Corydoras aenens (Gill) was nearly
100 per cent effective against chironomids. Anderson, et al (l9of+)
reported good control by carp, but poor control by catfish, bluegills,
sunfish and bullheads in water-spreading basins. Trout and suckers are
listed as predators by Leathers (1922), but Grodhaus (1963b) considers
trout as poor in this regard. Bay and Anderson (i960) found thas
Gambusia affinis fed on larval and adult stages of midges but 1 ailed
control populations. Since the rate oi adult emergence in any °i^e
depends on the original numbers of immatures and their rate Oj. develop¬
ment and replacement (Hayne and Ball,, 1956), fish predation as an ef¬
fective control measure is difficult to assess.
Control of larvae by other predators and parasices nas oeen men¬
tioned: (Ping, 1917 (cyclops); Leathers, 1922 (salamanders, dragonfly
naiads); Bonnel and Mote, 1941 (fish-roach and chub); Hunter, 1969
(microus paridian); Darby, 1962 (other midge larvae); Hilsenhoff, 1967)
hut no estimation of effectiveness has been made. The least sandpiper
(Erolia minutilla (Vieillot)) and American pipits (Anthus spinoletta
(Linn.)) were found by Anderson, et al (1964) to feed on midge larvae
in shallow water. Hilsenhoff (1963) obtained 98 per cent control of
\ 14
fourth instar larvae with the leech, HeloMella stagnalis, (Linn.;.
Chemical control of larvae has "been attempted by using many dif¬ ferent larvicides in a number of formulations, me oooanical insecti¬ cide rotenone was used at rates of 6 ppm and 10 ppm by j? ell ton (1940) to achieve control of G. lobiferus (Say) and other midge larvae. The same author (1941) obtained effective control with cnlorii-iaoed oenzeiiC.^ at rates of 16 to 25 gallons (192 to 275 Lbs of standard technical grade) per acre. Bonnell and Mote (1942; tested inorganic compounds in Klamath Lake, Oregon with little success. The chlorinated hydro¬ carbon insecticides have been used extensively for control. Elentje
(1945), Grant (i960), and Brown, et al (1961) achieved good to limited success using DDT in various midge habitats. TDE (Rhothane) was used effectively by Lindquist et al (1951) against the Clear Lake gnat
Chaoborus ostictopus Dyar and Shannon in a California lake and by Gerry
(1954), Jamnback (1954) and Brown, et al (1961) in ponds, a tidal stream and a river. The use of BHC in lakes is reported by Lieux and
Mulrennan (1956). The latter reported resistance in Glyptotendipes paripes (Edwards) to EPN and BHC gamma isomer. Jamnback (195*0 applied heptachlor to a tidal stream with no success. Anderson et. al (1964) tested lindane, dieldrin, DDT, methoxychlor, toxaphene and TDE in various formulations and achieved high to no success in water spreading areas in California. Although sometimes effective, the chlorinated hydrocarbon compounds have serious limitations in that many are moder¬
ately or highly toxic to fish and their residual activity may contam¬
inate food webs through the mechanism of biological concentration as 15
demonstrated "by Hunt and Bischoff (i960). Emphasis in recent years Has, therefore, turned to other chemicals, particularly the organophospnafce group. Malathion is often regarded as most promising for control but results of its use have been erratic. Grant (1960), Hilsenhofi ^19o2), and McFarland et al (1962) reported partial to no success in salt marshes, polluted 'waters, lakes and flood control channels. lTeadlpcs_ plumosus (Linn.) showed 96 per cent mortality five days after treatmeno with malathion granules at one pound per acre (Hilsenhoff, 1959)-
Hitchcock and Anderson (1963) reported similar control of Chironomus atrella (Townes) in a Connecticut tidal cove at the same dosage and for¬ mulation. The latter also found that Abate granules at rates of 0.1,
0.2 and 1.0 lbs. actual per acre was effective as was malathion gran¬ ules at 0.5, 1.0 and 2.0 lbs. actual per acre. Haled emulsifiable con¬ centrate absorbed on sand grains gave 90 and 93 per cent control at rates of 2.0 and 0 lbs. actual per acre, respectively. In no case in their study were all larvae killed by any treatment, strongly suggest¬ ing that there was an irreducible limit to larval mortality. Brumbaugh,
et a!L (1969) obtained excellent control in both field and laboratory tests with methyl parathion and fenthion quick breaking emulsions at rates of 0.44 ppm and 0.88 ppm, simulating 0.1 and 0.2 lbs. per acre. Ill. OBJECTIVES
The objectives of this study were:
1. To determine, by means of periodic surveys, the seasonal distribution and peaks of adult and larval populations of G. lobiferus
(Say).
2. To ascertain aspects of biology and behavior which might be of value in arriving at a method of control and/or an understanding of the seasonal fluctuations of populations.
3. To explore various methods of control of the egg, larva, and adult stages of the midge in the laboratory and in the field, and to evaluate the effectiveness of such controls.
16 IV. METHODS
A. Description of Study Areas
Two study areas were selected in the Holyoke - South Hadley Falls area (Figure l). Both were man-made canal environments and similar xn construction with regard to wall surfaces and wood piling structures.
The South Hadley canal area is located northeast of and adjacent to the Holyoke Dam on the east side of the Connecticut Fiver. Samples were obtained at a site approximately 100 feet long where the canal is approximately 3^ feet wide and b feet deep (Figure 3) • Fnis site is characterized by an overflow area where f lasnboards hao. been ins ocxlleo. to raise the water level. The flashboards and adjacent rock walls served as sites for egg deposition and larval habitation. The Holyoke
Canal area is a section of the second level Holyoke Canal approximately
2000 feet long situated on the west side of the Connecticut River just
t east of Route ll6 and adjacent to the Valley Paper Company and Brown
Company properties (Figures 2 and 3). The canal at this point is ap¬ proximately 100 feet wide and 30 feet deep. This site contains a
number of wooden ice fenders which jut out into the canal.
The South Hadley Falls site was slightly more than one-half mile
northwest from the Holyoke site in a straight line relationship. Pre¬
vailing winds generally were from the northwest or from the South
Hadley Falls site towards the Holyoke site. All specimens taken for
laboratory study were obtained at the South Hadley Falls site, whereas
all attempts at chemical control in the field occurred at the Holyoke
site. Since the wind direction was predominately down-river it seemed
17 Figure 1. Holyoke and South Hadley Falls study areas.
Scale : 1 inch = 625 feet. f
South Hadley Fails study area
i igure 2. Holyoke Study Area. Shows location of:
Adult Midge Adhesive Traps (Nos. 1 through 15 plus I and II located on canal ice fenders and traps A through N located on mill window screens).
Blacklight Traps (indicated by © )•
Adult Midge Resting Count Areas (screens observed in making analyses of insect¬ icide effects).. The adult resting count areas were subdivided as f ollows: Rabon treated - areas C,D,E,G malathion treated - areas H,I,K,N controls - areas A,3,EjJjM
A zone lp feet wide was left untreated between areas G and H to reduce the possibility of spray drift contamination of either treated area. Control areas were no less than 20 feet wide for the same reason.
Scale : 1 inch = lpO feet. Va!2ey pa?Q Co.
\ typewriter G\ Mill
Albion Mill
/ Srown Co / Office
^onotuck Twill Figure 3. South Hadley Falls study area
Holyoke study area.
21
unlikely that immigration of insecticide-treated adults into the South
Hadley Falls site from the Holyoke site was important.
Chemical control studies were made on the northeast side of the
Holyoke Canal area and involved the canal walls and ice fender
surfaces as well as the building faces and peripheral areas of these buildings. Care was taken to prevent chemical contamination of any sampling device or control area. 22
B. Sampling Procedures for Adults.
Light Trap Description and Method of Use
Commercial hlack light traps (Onarnia Manufacturing Co., Onamia,
Minnesota) were modified by attaching a large (15 inch by 18 inch) heavy duty plastic bag in place of a standard burlap bag, beneath the
1 intake fan of each trap (Figure 4). Plastic bags permitted much more effective collection of the midge catch than did the burlap in that specimens were more visible, fewer specimens were damaged, and more ac¬ curate counts were obtained.
A corner of the plastic bag was opened and the catch transferred to a smaller plastic sack, using the air blast from the fan to drive insects through the opening. The opening was then securely closed by fastening with a wire clip. The plastic sack was also secured with a wire clip and the catch transported to the laboratory for counting.
The location of light traps follows:
Canal Traps - 1. In front of the Valley Paper Company on
a frame 5 feet above the canal penstock opening (Figure 2).
2. In front of the Brown Company’s Albion
Mill in the same manner as 1. (Figure 2).
Fiver Trap - Located behind the Valley Paper Company on a
frame five feet above the ground adjacent to County Bridge
which spans the Connecticut River below the Holyoke Dam
(Figures 2 and 4).
The traps were operated continuously during the sampling periods except for infrequent cleaning and repair during daylight hours Figure H. Black light trap used in adult midge surveys.
i 23 24
after the catch had been removed.
In the laboratory the total catch of insects per each trap was removed from the plastic sack to a white enamel pan. The catch was
spread evenly in the pan and insects of other species larger than 1 cm were removed. (Size range of midges was 0.8 to 0.9 cm based on 100 measured specimens). A 1 oz. capacity measure filled level full (not packed) with a portion of the catch was found to contain 500 specimens
(actually 580 i 25, a 5$ error, based on 10 fillings). The number of measures of catch x 500 was used, therefore, as the total catch per unit time.
The number of midges in a total catch was obtained by counting the number of midges per measure (or per 500 insects) times the total number of measures. This method was selected after counting 10 meas¬ ures of the same catch. For this each measure of 500 insects was spread in the wnice pan and counted. Results indicated a maximum vari¬ ation of 10io between measures. In the first part of the sampling period mold developed in some catches held more than 2 days after col¬ lection and prevented accurate use of this counting procedure. Sub¬ sequently, all counts were made within 2 days of collection and any catches contaminated with mold were omitted from the study.
Adult Resting Counts
Adulu resting counts were made when measuring the effects of insec- tioide treatments. Initial observations indicated that many adults pre-
1 erred window screens as resting sites during the day. Reasons for this selection are unknown, but the screens may have had a lower temperature 25
than the surrounding surfaces. Except when screens were in direct sun¬ light, very little movement to and from these screens was observed.
Counts were made only on screens isolated from mill operations,, only when screens were shaded and only when wind effects on the screens were similar. Screens were 32 inches by 32 inches in size and located zero to ten feet above the observer. Accurate counts above this height could not be made because the small size of the midge made discrimina¬ tion difficult. Attempts to place a ladder in the area for better viewing were abandoned because they disturbed the resting midges.
In areas where high numbers of midges were found, both brick and glass surfaces as well as screens were observed (Figure 10). Records of adults resting on brick and glass were kept in a study of insec¬ ticide longevity on these surfaces. Square foot areas on the brick were inscribed in chalk. Numbers of midges resting per square foot were included in the square foot area. Glass pane resting areas were
13 1/2 inches by 9 3/^* inches (131.6 square inches).
Adult Emergence Trans
Energence traps were constructed of pine and 18 mesh aluminum window screen. A four-sided cone of screen two feet high was attached to a pine frame, having a basal opening two feet by two feet (so that four square feet of water surface would be sampled). At the small end
Ox the cone a pine block k inches by 4 inches was attached. The device
-was floated large end down in canal waters (Figure 5) and removed periodically for examination to determine the number of adult midges.
Ai-ter recording the counts all midges were removed and the sampler Figure p. Emergence trap used to collect adult midges shown in position near the ice fender of the Valley Paper Co. 26 reset for the next determination.
In studies measuring the influence of light on emergence, a 75 vatt incandescent light -was suspended immediately beneath the 4 inch by 4 inch pine block. Measurement of foot candles of light striking the water surface was accomplished by holding the trap 3 inches off the water surface and slipping the sensing element of a light meter between the trap and the water surface to a point where it intersected with the center of the trap. Preliminary test readings averaged 26 f.c. illumination. The trap was then floated on the water. Samples were collected at one minute intervals. After recording the number emerged, the trap was cleared of all insects and again floated, but this time with the light off. Subsequently, alternate samples were taken in the light and in the dark.
Adult Adhesive Traps
Adhesive traps were prepared by cutting l/4 inch unfinished ply¬ wood into 6 inch squares and painting one surface with Stikem Special
(Michel & Pelton Co., Emeryville, California) in a layer 1/8 inch deep. These traps were placed in both the South Hadley Falls and
Holyoke areas in attempts to provide an index of the number of midges per o inch square per 24 hours. From these data, seasonal distribu¬ tion and peaks of emergence were calculated and the timing of insec¬ ticide applications to the buildings were made for the Holyoke area.
In the South Hadley Falls area one bank of five traps, each two feet apart, was set 6 inches above the water surface. Each trap was nailed to a plank set 2 feet above the water on a platform overhanging Figure 6. Adhesive traps located on mill window screening and near the canal water surface in the Holyoke study area. 28 29
the canal. Counts of midges per 24 hours were kept from June 11 until
August 1; 1970> when an explosive emergence in the Holyoke area forced termination due to lack of time in which to service traps adequately.
In the Holyoke area two hanks of traps were set (Figures 2 and 6).
One set of 20 traps was nailed to wood surfaces 6 inches to 2b inches above the water surface (water fluctuations in this area prevented establishment of a standard distance; however,, except at times noted -
August 9 and l6, water level was maintained within these 2 distances).
The actual sites selected for position were the six ice fenders
1 located within the study area (Figure 2). Beginning at the north end of the area, ice fender No. 1 held four traps (traps 1 to 4). This pattern was repeated on the next two fenders (traps 5 to 8 and 9 to
12). Fenders Nos. 4 and 5 held three traps each and fender No. 6 held two traps. None of the traps above on any fender was closer than 4 feet nor greater than 12 feet from any other trap. The ice fenders are spaced approximately 350 feet apart.
Another bank of 15 traps (A through N) was set on the screens of the mill windows which were located 30 feet from the edge of the canal
(except for 2 traps (J and K) located approximately 60 feet from the canal). All of the traps on the windows were 6 feet to 10 feet above the ground or 9 feet above the water surface. These traps were held in place on the 18 mesh/inch screening by means of a wire hook which was forced through the holes of the screen. The purpose of the traps was to obtain an estimate of the number of adults alighting on the screens per 24 hour period. Every 24 hours, or other period noted, counts and records of
trapped midges were made. All insects on each trap were removed by means of a small metal spatula and discarded. (When numbers per trap
exceeded 200, only 1/4 or l/2 of the trap was counted and cleaned).
Numbers were recorded as number per 6 inch square after multiplication by 4 or 2). Each time a trap was read, an inspection was made of the sticky surface and either existing Stikem was redistributed or more was added to obtain the l/8 inch coating. Damaged or weathered traps were replaced.
In the Holyoke area, whenever insecticide treatments were made, either the traps were removed and placed in a sheltered location, or sites containing the traps were not sprayed and spray drift was care¬ fully controlled to prevent contamination (Figure 2).
Method of Sampling Swarms:
Dusk swarms of mating midges were sampled by means of a trans¬ parent plastic cup 4.8 cm in diameter and 4.4 cm deep. The cup was held in che paim oi the hand and swept briskly through the swarm at the 6 foot level above the ground. At the end of the sweep the other hand was clamped over the opening prior to cessation of the sweeping motion. Counts of catch were made through the transparent sides of tne cup with the aid of a flashlight. Withdrawal of the hand from the open end and slight shaking freed any midges caught and the device was ready for the next sweep. 31
C. Sampling Procedures for Larvae.
Square Foot Samplers:
Twelve samplers were constructed of 1 inch unfinished pine hoard cut to square foot size (Figure 7). A3 foot long handle was fastened to one side of the pine hoard leaving the other surface free from obstruction. A square of transparent acetate was attached to this sur¬ face hy means of staples. These devices were lowered into the canals in various locations at depths of 6 inches to 12 inches and nailed in position through the handle. After prescribed time intervals the samplers were raised and b or more one inch square samples of acetate were cut off with scissors. During the time the sampler had been sub¬ merged, various organisms and debris had become attached to the acetate. Removal of the sampler from the water and cutting the acetate into inch squares failed to dislodge this adherent life and each sample thus collected was placed in 20 ml of distilled water in separate containers; and transported to the laboratory where a daily examination for organisms was made. Midge larvae in tubes could easily be seen and counted by simply turning the square of acetate so that the debris-covered face lay on the bottom of the collecting container. The entire midge tube with midge, if present, could be examined with ease through the transparent acetate. Considerable shaking and turning of cue sample failed to dislodge these larvae so long as they remained sub¬ merged in water. The numbers of larvae adhering, plus those free in the sample water, constituted a record of larvae per square inch. Lar¬ vae attached in approximately equal numbers to the acetate and un¬ covered submerged areas of the sampler and adjacent ice fender surfaces. Figure 7. Square foot samplers with acetate facing used to survey selected aquatic animals in canal waters. 32 33
Method of Survey in Drained Canals:
In the period October 19^7 to July 1971> during eacn of one tnree regularly scheduled drainages per year of the canal in the Holyoke
% study area, a survey of the numbers of larval midges was made. These larvae inhabited the rock “walls, rip-rap, stone footings and wooden ice fenders in the canal which were inaccessible for inspection except when the canal was empty (Figure 8). Samples were taken at eight locations and represented no fewer than three inch square subsamples at each location. These subsamples were not randomly selected and no statis¬ tical analysis was made of the data. Numbers of larvae present were ascertained by carefully scraping inch square areas with a scalpel so as to remove completely adhering debris and larval tubes. All active
larvae in the 2nd or later instars were counted and recorded. Average numbers per square foot were obtained by averaging readings taken and multiplying by ikk. This transformation did not imply that each square
inch in the square foot yielded similar numbers but did convert the
readings to a surface area measurement more easily visualised by paper mill and power company managers to whom regular reports of the survey were sent. Figure 8. View of the drained canal in the Holyoke study area adjacent to the Brown Co. office building. # 3h 35
D. Sampling Procedures for Hggs.
Egg masses laid on the canal wall and ice fenders were countea when the Holyoke canal was lowered on August l6, 1970. Areas o incnes by 6 inches were measured and marked out by scratching lines in one debris found around the masses. Numbers of egg masses per uni o were counted and recorded. Where canal walls were uneven, the o inch by
6 inch areas were estimated. Sampling areas were not randomly selected and no statistical analysis was made of the data recorded. 36
E. Miscellaneous Sampling Procedures.
Method of Measuring Wind Velocity, Light Intensity, Relative Humidity and Temperature:
Wind velocity was estimated using the Beaufort Wind Scale modified for use on land. A Canadian hemlock tree 10 feet in height adjacent to the study site was observed for twig and branch movement and the wind speeds estimated from this movement.
Light intensity was measured with a Weston Illumination Meter -
Model 756 with quartz filter (Weston Electrical Instrument Corporation,
Newark, N.J.). This instrument measures intensity in foot candles, or lumens per square foot evenly distributed. Readings were taken at the same site and same position every time. Method of use involved turn¬ ing on the instrument and allowing at least a one minute warm-up. With sensing element held parallel to the surface of the ground at a height of 6 feet, at least three readings were made in the low range. Other readings at times of adult emergence were made while holding the sens¬ ing element parallel to the water surface at a height of 3 inches.
Relative humidity was measured by a sling psychrometer (Bacharach
Co., Pittsburgh, Pa.). Again, three readings were converted to per cent relative humidity using a nomogram.
Temperature readings were made with an armored thermometer (-30°F to +120°F in 1 degree divisions, Taylor Instruments, Asheville, N.C.).
Air temperatures were taken at breast height (5 feet above ground) and canal water temperatures at a depth of 6 inches below the surface. measurement of Dissolved Oxygen, gH, and Turbidity of Canal Waters:
Dissolved oxygen was measured by means of the Standard Winkler 37
Method (Alsterberg modification using phenylarsene oxide (PAO) instead of sodium thiosulfate for the titration of iodine because PAO is completely stable). A portable field type testing kit (Model 0X-2-P,
Each Chemical Company, Arnes, Iowa) was used for all determinations.
All readings were taken at the same locations at a depth of 6 inches.
Temperatures were taken at the same time and depth by means of an armored thermometer so that per cent oxygen saturation of the water could be computed.
Studies of pH and turbidity were made from water samples taken from the same sites as the dissolved oxygen samples. A 250 ml Erlen- meyer flask was filled with water from the 6 inch level by thrusting the empty inverted flask to this depth, righting it, allowing it to fill completely, then quickly pulling the sample out and stoppering it immediately. No samples containing air bubbles were retained. The sample was then transported to the laboratory and tested for pH and turbidity. No attempt was made to maintain water temperature of the sample, but exposure to high temperatures and direct sunlight was avoided.
The pH of the sample was measured by means of an electronic pH meter (Central Scientific Co., Chicago, Ill.) laboratory model No.
21660. Before each measurement, the instrument was standardized, using a standard buffer mixture having a pH of 7.
Turoidity was measured by means of a colorimeter (Hach Direct Read¬ ing Model No. 5S5, battery operated, Hach Chemical Co., Ames, Iowa).
Ine amount of turbidity was read in Jackson Turbidity Units - Formazin 38
Standard, and was compared to a distilled water control which had been adjusted to zero units. Since water samples were never highly colored,, filtering vas unnecessary- 39
MjLdp;e Control Procedures - Laboratory,.
The insecticides Abate, malathion, Waled and Rabon, all emulsifi able concentrates, were tested in the laboratory. None of these in this formulation had been tested against this species of midge before as revealed "by a search 01 "the lioeiaouie.
and Drying Effects on Eggs: Method of Testing Insecticidal
Eggs were collected for all laboratory tests at the South Hadley
Falls study site. Egg masses were removed by forceps from samplers
and/or rock surfaces and placed in collecting containers in 25 ml ox
distilled water. Only eggs three or more inches below the canal waters
were selected in order to exclude those which might have become deo-
sicated due to changes in the canal water level. During transit to
the laboratory, n0 attempt was made to control temperature of eggs,
but high temperatures and direct sunlight were excmudea.
In the laboratory egg masses were examined by means of a low power
dissecting microscope to detect mechanical damage, Mie misc g 01. pi
tion and the approximate stage of development, Eggs selected for
treatment were those which showed positive signs o^. development (darken¬
ing of center of egg) but had not progressed to a prehatch stage in
which the egg undergoes elongation. Ho other attempts were made oO
determine egg age.
Egg masses selected for treatment were removed from the collecting
vessel and placed on a clean microscope slide. Under 10X magnification,
each egg mass was sliced into clusters of eggs (replications) by means
of a razor blade. Each cluster was examined for physical damage before 40
placement in a one ounce paper cup. Transfer of the cluster was made by a small acetate point which facilitated fixing the sticky matrix in the bottom center of the cup. Clusters adhering to the sides of the cup could be observed only with difficulty. Every attempt was made to reduce the amount of egg cluster movement once it was placed in the cup so as to reduce physical damage. The egg mass on the microscope slide was bathed in distilled water as needed to prevent drying, except in dessication studies when eggs were air dried for 1, 1.5 and 2-hour time periods at 72° to 76°F and 65$ relative humidity. Insecticide solutions to be tested were adciea. to the cups ^10 ml in eacn) genolj/
so as not to disturb the position of the egg cluster in the center,
count and record of the numbers of eggs per cluster was made prior to
covering the cups with plastic film to prevent evaporation.
After incubation at 72 to 7^°E for the prescribed time interval,
or until all controls had hatched, the plastic vapor barrier was re¬
moved and the eggs counted under the dissecting microscope. Numbers
hatching were recorded and the cups were again placed under the vapor
barrier for a minimum additional time period of 10 hours to ascertain
any delayed hatching. Hatching was defined as any extrusion of the
larva’s body through the covering of the egg.
Method of Testing Insecticide Effects on Larvae:
Eggs were collected as indicated in the egg studies. Eggs were
allowed to hatch in the collecting vessel, and the larvae were allowed
to free themselves from the surrounding matrix. Once free, the larvae
could be pipetted up in a small amount of water (estimated at l/20 ml) 41
Ten ml of the solution to he tested were pipetted into each l/2 ounce uaper cup# Larvae were then added with a pipette ana tne numbei s
counted and recorded, after which all cups were covered with a plastic
vapor harrier to reduce evaporation. After the prescribed treatment
time each cup was examined for the number of larvae still living.
Death was defined as a lack of body undulations and absence of move¬
ment of body appendages of digestive tract when gently probed.
Modifications of the above procedure were necessary when treating
larvae which had built tubes on the square foot acetate samplers.
Square inch sections of acetate containing larvae in tubes were col¬
lected in the field and placed in collecting vessels in 25 ml of
distilled water. These samples were transported to the laboratory and
each sample immersed in a prescribed insecticide emulsion (1000 ppm)
prior to being placed in a paper cup containing 15 ml of distilled
water. The cups containing the samples were then covered with the vapor
barrier as in other tests. After specified time intervals the larvae
were examined for lethal effects of treatment and possible behavior re¬
actions to the chemicals. Examination involved turning the acetate
film over to view both sides as well as observing all specimens which
had left the tubes.
Method of Testing Insecticide Effects on Adults:
Adults used in tests were collected at the South Kadley study
site. Resting adults were aspirated into 1 ounce polystyrene plastic
collecting vessels (Eigure 9). When the number to be used in each
replication of the tests (usually 10) was reached, the aspirator was 42
removed from the vessel and the opening quickly closed with a cardboard
cover, 'transportation to the laboratory and subsequent treatment occur¬
red without further transfer of specimens. This technique reduced
chances of escape by adults and reduced mecnanicaj. injuries.
Tests of insecticides in the laboratory were conducted by first
treating aluminum 18 mesh screen cages with an emulsion of insecticide.
Cages were constructed (Figure 9) by cutting 6 inch oy 3 laCii rectan¬
gles of screening and rolling each into a 3 inch long cylindei opu. a^
both ends. The cylinder was fastened with SF - 1 staples using a com¬
mon paper stapler. A plastic collecting vessel was inserted inuO ^ne
open end of the cylinder to get a proper size measurement for later at¬
tachment to a vessel with midges. The opposite end of the cylinder was
pressed flat and fastened together with more staples. This completed
cage was now immersed completely in insecticide solution for 3 seconds,
then removed and allowed to dry until drip-free. In studies involving
longevity of insecticide effects, the cages were allowed to air dry for
48 hours before use.
Collecting vessels containing midges were unsealed by removing the
cardboard cover and quickly fitting the open end of the vessel into the
open end of the cage. (See Figure 9 for a view of the assembled test
chamber.) Each test chamber was placed on a sheet of plastic film to
prevent absorption of the insecticide from the screen. The entire
apparatus was fixed on the plastic at a slight angle so that midges in
the collecting vessel could enter the cage section either by flying or
progressing down a 25° slope. Only those insects which could move out
« Figure 9. Aspirator and collecting vessel used to collect adult midges for laboratory insecticide treatments.
Aluminum screen cage with collecting vessel attached used to enclose adult midges during laboratory insecticide treatment. hj IV . 44
of the collecting vessel were counted and recorded as alive in each replication.
Tests on the adults were run for 10 hours exposure time. At the end of this period, the number of live adults was counted ana re¬ corded. Live was defined as the presence of movements of the body or appendages when cages were shaken and the specimens were gencly probeu..
At the start tests were conducted to compare controls which had been treated by immersion in distilled water and those wnich had no treat¬ ment. Since no differences between these were found, all controls in subsequent insecticide tests were left untreated.
Method of Testing Effects of Cold on Larvae:
larvae were exposed to a sub-freezing temperature to see if canal
drainage during the winter would be a practical approach to reducing midge numbers. Larvae in the 4th instar were collected in the Holyoke
study area during the October 24, 1970 canal drainage. Stones approxi¬ mately four inches in diameter were taken from the bottom of the canal which still contained several inches of water. A water temperature of
56°F was recorded. The stones were removed to the laboratory in flat
pans containing enough canal water to keep all tubes submerged. This
method ensured that the larvae remained relatively undisturbed in their
tubes and were never exposed to prolonged dessication. The stones were
not randomly selected and no statistical analysis was made of the data.
In the laboratory gentle probing confirmed the presence of active
larvae in the tubes. The stones remained submerged and were divided
into twolots, designated either as treated or controls. Ten square 45
inches of stone surface were selected and marked in each lot and counts of the numbers of larvae were made and recorded. The square inch sites were not randomly selected.
The control lot was covered by a plastic vapor barrier and left in the laboratory at a temperature of jk ± 2°F. The treated lot was placed in the freezer compartment of a refrigerator for 22 hours where the temperature was 3°F. At the end of 22 hours the treated lot was removed from the refrigerator and allowed to thaw at a room tempera¬ ture of 74 + 2°F. At the end of 24 hours both lots were counted and the number of live larvae recorded. Both lots were then maintained at
74±2°F. i or an additional 32 hours when another count was made to ascertain any delayed recovery. G. Midge Control Procedures - Field.
Mechanical Control - Adults:
This involved screening and ensuring that openings into "buildings remained closed. The security lighting patterns around the buildings were altered in order to reduce illumination of buildings and adjacent areas after dark when emergence was occurring. Quantitative data were not obtained here, with the exception of records of numbers of midges found in adhesive traps located on windows before and after ’’blackout'1 conditions existed. ’’Blackout" was defined as complete exclusion of all artificial light from fixtures on the outside of buildings facing the canal, with the exception of a single light trap sampler located in the Valley Paper Company area. Artificial light within the building was not altered, and passage to the outside through windows, doors, and other apertures was not controlled.
Physical Control - Bggs:
Physical control of the egg stage involved the withdrawal of water from around deposited egg masses located in the canal. This was done by lowering the canal level by a given amount and stranding the egg masses on the peripheral areas. After lb hours drying the canal was refilled, samples being collected just prior to refilling. Control egg masses were collected only from areas which had remained submerged.
Another physical method tested was heat treatment of stranded egg masses designed to speed up the drying process and/or alter the proto¬ plasm of the eggs to a point where they would not hatch. This was ac¬ complished by beat treating a limited number of egg masses for varying lengths of time. The heating device used in these trials was a kero¬
sene-burning brush eradicator capable of producing a flame up to 15
inches long. hTo attempt was made to calculate temperatures of either
the burner or the egg masses treated. All treatments were made hold¬
ing the burner no closer than 6 inches from the egg mass. The col¬
lection and handling of egg samples was accomplished in the same fashion
as previously described under laboratory studies on eggs.
Insecticidal Control - Adults:
Two insecticides,, malathion and Rabon (see Appendix for chemical
descriptions and sources) were used in attempts to control adults.
Both were emulsifiable concentrate formulations. Because of the habit¬
ual seleccion by adults 01 screen resting sites,, treatments which were
analysed concerned only these surfaces. Actual application of these
chemicals was made to the entire face of all buildings bordering the second level canal up to a height of 20 feet. Any structures tempo- xa-i.-i.ly located in the area were also treated (boxcars, wooden crates, etc.). Loading platforms, ramps, adjacent vegetation, fencing and other likely resting sites between the building zone and the berm of the canal were included for treatment. In short, an attempt was made to create a barrier zone of insecticide so that midges alighting anywhere in the zone would contact either Rabon or malathion.
Treatments with the insecticides were made repeatedly on a daily or several-times-weekly basis, timed as nearly as possible to times uhen midge emergence was greatest as determined by adhesive traps in the area. Amounts of chemicals applied were at the following rates: 48
Rabon - 1.0 lb. actual chemical per 100 gallons of spray. 25 gallons of finished spray used each application.
malathion - 1.4 lb. actual chemical per 100 gallons of spray. 25 gallons of finished spray used each application.
All window screens except controls were sprayed to point of run-off.
The application period extended from July 14 to August 30^ but quanti¬ tative data were recorded for only six applications because of either a failure to record resting counts of adults on screens or because environmental conditions were not favorable for such counts. After
August 8, the treatment dosages were doubled. Application to both treated and control areas was made in an attempt to combat an explo¬ sive outbreak of midges which had successfully breached the insecti¬ cide barrier zone. Quantitative data on these treatments were not obtained.
Limited tests were made in a selected area some distance from the canal (Figure 10) to assess the longevity of malathion on brick and glass surxaces. After treatment with 1.4 los. actual malathion in
gallons ox finished spray_, sprayed to point of run-off, resting counts were made on seven successive days.
Insecticidal Control - Fggs:
a total Ox 40 gallons Ox malathion emulsifiable concentrate as a mixed spray (1.12 lbs. actual) was applied to point of run-off on egg masses stranded above the water level in the drained canals. A zone four feet wide and approximately 1000 feet long was actually treated.
Samples were collected after one hour exposure and unsprayed eggs were collected for comparison. Collection and handling methods were the 10. Brick wall and glass pane surfaces to which malathion was applied in studies of length of time agent remained effective.
50
same as those previously described for the laboratory procedures.
Insecticidal Control - Larvae:
Malathion emulsifiable concentrate was applied at a rate of 1.4 lbs. actual per 100 gallons of finished spray to the canal walls and ice fender surfaces on four dates (July 1, 1968; Jul 2, 19^9* May 10 >
1970; July 6, 1970) at rates ranging from 20 to 100 gallons. Applica¬ tion was made with either a back-pack fogger or a truck-mounted sprayer (Figure ll), after canals had been drained for at least 2b hours. The treatment area boundaries were the Brown Company (Gill
Mill) ice fender and the Route ll6 bridge beside the Valley Paper
Company. Only the paper mill property side of the canal was treated.
The insecticide was applied to point of run-off on ice fender surfaces and to canal wall areas showing evidence of occupied larval tubes. A pre-spray survey of larval numbers was made and numbers were recorded.
No quantitative data on numbers surviving the treatments was recorded, ■ j but observations on the condition of larvae which had left their tubes because of either the spray, dessication or both were made shortly after the treatments were applied.
It is important to note that insecticide tests of larvae in the laboratory were made by immersing the larvae in the test emulsion, while in the field studies exposed larvae were sprayed with insecticide Figure 11. Truck-mounted power sprayer used to apply malathion to walls of drained canals.
Malathion being applied to ice fender surface by the author. 5l V. RESULTS AND DISCUSSION
A. Survey of Adults.
Numbers of adult midges present at sites near the Valley Paper
Company in the Holyoke study area and near the adjacent Connecticut
River were measured by two black light traps during the period 10 June
to 1 September in the summer of 1969* Results of this survey are sum¬
marized in Figure 12 and Table 1. In both areas numbers were highest
in mid-June and mid-July with a final and smaller peak in late August.
Numbers were consistently higher in the Valley Paper Company trap after
July 1, 1970, suggesting the importance of the canal as a source of
adults in mid and late summer.
During the period 28 April to 6 September, 1970, the two black
1-tgho traps were again operated in the same areas. An additional trap
was operated in the Brown Company area adjacent to the Holyoke study
area from 27 May to 11 August, 1970. The results of I970 are found in
Figures 13, lb and 15 and Table 2. Again the numbers caught were
higher in the canal traps than in the river trap during the times of
maximum emergence after the first week of July.
During both summers the numbers caught near the river and near the
canal appeared to fluctuate equally with respect to each other. The
reasons for these fluctuations are unknown, but the data suggest that
the factors promoting population increases are common to both river and canal habitats. Therefore, control methods concentrated only in canal areas would at best, provide only partial relief from the adult midge nuisance.
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Mill Window Traps Ice Fender Traps Mean No. Mean No. midges midges Dates trapped trapped June 19-25 6 15 June 26 3 6 July 2-3-9 5 7 July 10-16 13 26 July 17-23 29 99 July 24-30 21 39 July 31 360 599 Aug 6-7-13 1,038 2,253 Aug 14-20 688 1,333 Aug 21-27 403 877 Aug 28 448 1,288 Sept 6-7-12 129 346 Table 4. Adhesive trap data (6 inch by 6 inch panels set on ice fenders 6 inches to 24 inches above canal waters - Holyoke study area). Actual numbers of midge adults trapped per unit time during the summer of 1970* « ■p 0) w ctf No* NO 00 vo vo < VO c- NO VO VO CO VO NO CVI CO 1 I ft ON CVJ 2 3 o voco rH r-J CVJ ft-4 5$ CO CO VO co -4 VO NO 4 CO NO CO CO -4 co I—J o o ITN on I—1 o o o CVJ OJ CVJ CVJ CVJ rH on ON ON o rH CVJ o on CVJ o on ITN CVJ CVJ o 5 6 L CO Oht—ON-4NO ft O -4CVJ _4 I—I ,4- vo vo o vo ON VO LTN -3- CVJ vo o 8 00 CO -4 VO -4 co co vo -4 CVJ vo o CO VO CVJ rH i—I O co ON CVJ CVJ rH rH r—i on rH CVJ r—I LTN o CVJ co O -4 O rH o cvj O co o O co O VO CVJ rH CVJ o CVJ rH o LTN CVJ LTv ft CVJ NO on cvj O ON O CVJ O -4 on on OJ ft 6 CO CO rH 0 ft CVJ CVJ o ft ft CVJ vo -4 CO -4" co co CO CO CO -4 CO I—1 rH ON CVJ o o ft on o ft o CVJ CVJ LTN cvj o on CVJ ft CVJ o on CVJ CVJ o o on CVJ on on CVJ ON CVJ O CVJ ft ft onH4 -4 co CO vo co CO co co vo co LTN CVJ CVJ ft CVJ OJ rH ON CVJ t CVJ LTN OJ CVJ O O ft o on OJ O O -Si¬ ft CO rH o ft LTN cvj rH on ojoltn CVJ rH O CONO-4 on ITN-4ft ft H LTN ftVO CO VO CVJ -4 8 vo o -4 -4 -4 ft -4 VO CO VO CVJ -4 00 ft OJ rH on CVJ LTN CVJ o co c— OJ CVJ ft on ft CVJ CVJ CO OJ o c— VO CVJ on -4 on o on ft ON LTN -4 O O VO IN- NO on ON rH o on OJ o ft OJ -4 vo -4 CO vo CO vo vo 1—l rH o rH vo OJ CVJ O rH vo LTN CVJ rH o o o CO O CO rH c o ft ft 1-4 O' co co oj NO • -4 VO NO O -4 VO -4 • -4 CO CVJ -4 -4 -4 K4 oj -4 • -4 co NO -4 • LON • i—I r—I -4 CO -4 _4 • i—1 ft CVJ OJ ON OJ o • IfN [— LTN ft CVJ • o • -4 CVJ o • ft OJ -4 CVJ OJ OJ -4 o on ON c OJ O CVJ ON CVJ o CVJ CVJ ft O co ON CO on-4 OJ on CVJ OJ ft OJ rH CVJ Eh < o NO H p bJD o -3" • OJ ft OJ -4 O rH O > I I—I • co CO -4 VO VO NO rH i—i on on! on on cvj o ft OJ on OJ 1-1 ft OJ on cvj ft OJ OJ ft cvj on on on ft ft • • • 70 Table 5. Adhesive trap data (6 inch by 6 inch panels set on mill-window screening - Holyoke study area). Actual numbers of midge adults trapped per unit time during the summer of 1970. OQWP^OWh^W OOOHOnH HOJWHOHon rH OpH O «H 1—I OrH OOOOOr—IOOO 000000000 000000000 OOCVJOOCUOOCVJ OHOOOHdlrlH ojcvjoncnojOiHcvjvo H OOJ O -4-00 O rHo o 000 OJ rHoO »H * P td P -P •H td rG € P -p P •H •H P 0 p -p ■p G G G td o G 0 td G G 0 to ,C -P *H rG td O cd G £ & o p to G cd 0 £ G td G rG 0 cd O to •H G a 8 -P 0 to to td G cd P ps >3 td 0 G •H td pf -P rG to G similarity. The 19&9 data show a higher peak in mid-June,, then a gradual decrease and another peak in mid-July. The 1970 data show a small June peak; a sudden decrease in late June and a gradual increase through July, and a final, extended high peak throughout the month of August. This latter peak created intolerable nuisance conditions in the Holyoke study area and was not responsive to insecticidal treat¬ ment after August 8, 1970* The reasons for these differences between the two years are un¬ known. Hilsenhoff (1966) records a variation in yearly life histories of C. plumosus in Wisconsin. Reiss (1968) reports similar July and August emergence peaks and Darby (1962) records a similar year to year variation in emergence numbers. Data collected over a number of years would be essential in order to arrive at any accurate generalizations. The value of the light trap technique was in indicating when nuisance levels of adults might be expected and in pin-pointing the Connecticut River as a major source of midge reinfestation. B. Survey and Control of Eggs. A survey of the number of egg masses found adhering to wooden ice fenders and canal walls was conducted on August 17, 1970. These data are summarized in Table 6. The upper two feet of the drained canal contained 71$ and 79$ of the egg masses counted on ice fenders and canal walls, respectively. The 2 to 4 foot level contained the remain¬ der of the egg masses counted. Ifeg masses were observed below the k foot level, but their jaumbers were insignificant in comparison with Table 6. Number of egg masses found per 6 inch by 6 inch surface, Holyoke Study Area. August 17, 1970. Wood Ice Fenders Rock Canal Wall Surface to 13 n Two Foot Level 12 10 14 13 18 32 15 27 18 17 25 9 30 44 12 24 10 37 Total T&f 225 Mean 16.7 22.5 (71$ of samples (79$ of samples taken in both taken in both levels) levels) Two Foot to 7 8 Four Foot Level 1 4 2 5 0 3 6 4 3 5 10 6 12 3 4 4 77 those above. On rock wall surfaces masses tended to cluster into bunches of 20 masses or more,, particularly where rockwork was irregular or where there was debris. Egg masses sink in water unless they en¬ counter an obstruction to which they may adhere by means of the gelat¬ inous matrix or the suspensory stalk. This observation corroborates Fischer s (1969) findings on Chironomus nuditarsis Str. E^jgs deposited in open water presumably would sink to the bottom of the canal, but this was not ascertained since the canal was lowered only four feet. Observations in drained canals on other dates did not yield egg masses attached to the bottom of the canal. Effects of Dessication on Eggs - Field: On August 8, 1970 egg mass samples were collected from ice fender and canal wall surfaces after being exposed to air for 14 hours. These samples were treated in the same fashion as those mentioned previously m the laboratory study. The results are given in Table 7. A mean per cent hatch of 50$ was obtained as compared to a 99 $ hatch in controls. Much variation between clusters existed, ranging from 0.0$ hatch to 91.9$ hatch. This may be the result of differential drying rates of clusters based on the amount of moisture available at the collection site. Egg masses located within rock crevices, for example, were ex¬ posed to pools of moisture for longer periods than masses found on flat rock faces. — e-c-fc-g- — Dessication on Eggs - Laboratory: Egg masses collected in the field were divided into clusters of 5 to 32 eggs, each cluster having a surrounding film of gelatinous matrix Table 7. Hatching of midge egg masses after 14 hours of exposure to drying on canal walls and on ice fender surfaces. Number of eggs Number Per cent ReP in cluster hatched hatched 1 89 T7T 44.9 2 73 65 89.0 3 79 2 2.5 4 60 0 . 0.0 5 36 27 75.0 6 75 0 0.0 7 86 79 91.9 8 110 93 84.6 9 53 42 79.3 10 63 0 0.0 11 47 .... 39 83.0 Total 771 387 i§ LT\ Mean 70" ...... 35 Control A 47 47 100$ Control B Co .. 57 99 i Total 105 104 Mean a . 92 99 f 79 When exposed to air in the laboratory for 1, 1.5, or 2 hours on clean microscope slides, the following results were obtained. 1. At the end of 1 hour des si cation only 1 Gjo of the exposed eggs hatched. 2. At the end of 1.5 or 2 hours exposure no hatching occurred. 3. Controls showed 100$ hatch at the end of 2 hours. These field and laboratory results involving the egg stage support Kimball's (1968) findings that dessication may be an effective control procedure. Control of Eggs by Heat Treatment: This is the first known report on the control of midge egg hatch- ing by this method. Heat treatments of egg masses using a flame throw¬ ing brush burner were extremely effective in preventing egg hatch. Both 10 and 20 second exposure to the flame resulted in zero hatch as compared to 91$ hatch in controls. These treatments are summarized in Table 8. 1 Control of Ij^ggs by Insecticidal Treatment: Malathion was applied to point of run-off at a rate of 1.12 lbs. in 40 gallons of water to exposed egg masses. The results are found in .table 8. A mean of 84% hatch of malathion-treated eggs indicated that the chemical was quite ineffective. However, larvae hatching from these eggs succumbed within 2 days after hatch. Controls showed 91% hatch and all larvae were alive 2 days after hatch. A search of the literature revealed that no previous attempts at midge egg control by malathion E. C. had been made. c• Survey and Control of larvae. 80 Table 8. Effects of brush burner and malathion treatments on the hatching of midge eggs in the Holyoke Study Area. Number Number hatched Per cent Delayed Treatment Rep . eggs after 2 days hatched hatch 1 48 2 39 3 42 Heat - 10 sec. 4 37 exposure 5 21 none none none 6 4l 7 47* 8 47 9 44 10 66 1 37 2 51 3 4l Heat - 20 sec • 4 56 exposure 5 68 none none none 6 47 7 54 8 57 9 102 _10 o 93 2 39 24 62 3 46 32 78 Malathion 4 51 46 90 none 1.12 lbs. ap¬ 5 45 38 84 all hatched plied in 40 6 44 4o gallons of 91 larvae dead* 7 44 36 82 by Aug 20. water 8 32 29 91 9 28 93 10 19 '9 1 23 100 2 48 46 98 3 34 33 97 none 4 53 52 Control 98 all hatched 5 59 56 95 larvae alive 6 32 31 97 on Aug 20. 7 24 22 8 92 17 12 71 9 47 43 92 10 62 4o 65 is • 81 1. Field Studies: Records of numbers of second, third and fourth instar larvae in the Holyoke study area we re kept from October 1967 through July 1971. Table 9 and Figure 17 indicate levels found per square foot of sampled sur¬ face. These records were obtained during periodic drainage of the canals and represent a minimum of 3 subsamples, each a one inch square collected at each sampling station. Samples were not randomly col¬ lected and no statistical analysis was made of the data. Larval numbers were at their highest levels during the October inspections vita the exception of 1969 when the yearly peak was reached in May. Lowest levels were found in July in all years sampled except 1970. During this 3 l/2 year period, k treatments of malathion were applied at the rate of 1.4 lbs. actual malathion per 100 gallons of finished spray. These treatments occurred on July 1, 1968, July 2, 1969, May 10. 1970 and July 6, 1970. Although larval midge populations were gener¬ ally at lowest levels in July, this was the only practical treatment time since drainage was extended beyond 2k hours only during the July drainages (except for May 1970). When canals were empty 2k hours or less, it was impossible to apply a satisfactory treatment because of the dilution effect of either residual or inflowing water. Also, there was insufficient time to make valid before and after treatment inspections unless canals were empty at least 2 days, tte institution of small scale treatments based on a randomized design of sample col¬ lection would be a valuable adjunct to these studies. Spot checks in the canal after treatment indicated that the malathion and dessication 82 reduced larval populations to near zero in every inspection. Larvae we re declared dead if they were immobile or if they exhibited erratic movements and tremor when probed. Although Hitchcock and Anderson (1968) report successful field control of Chironomus sp. larvae with malathion granules, the emulsion treatment reported here apparently was unsuccessful. In fact, after the insecticide applications, numbers of larvae increased sharply and exhibited characteristic peaks at the time of the October 1968, 1969 and 1970 inspections. This suggests that recolonization of treated habitats by larvae was rapid (larvae built tubes on untreated acetate samplers within 5 days after immersion in canal waters) and that the malathion treatments were either ineffective or of brief duration. Although rate of colonization of treated areas was not measured, egg maoses reappeared in the filled canals within 5 days after treatment. Since larvae in the first instar could not be identified by the survey method used, survivors in this stage may have contributed to the sub¬ sequent sharp increase in larval numbers. Larvae washed in from un¬ treated areas and the progeny of immigrating females may also have in¬ fluenced these numbers. No malathion emulsion treatment was made in 1971. Mean numbers of larvae found in the October 1971 inspection were slightly higher than the numbers found in October 1969, but con¬ siderably lower than numbers found in the October inspections of 1967, 1968, and 1970. This information further suggests that the malathion treatment has a limited effect on seasonal populations and that other variables in the environment have at least as much effect in reducing larval numbers. 5 Table 9« Numbers of midge larvae per square foot of campled sur¬ face in the Holyoke study area during periodic drainages 1967-71 •P •H Sampling rN r— O 0 CO ON Oct. o rH o Station i— 1970 \ CO(N-0000OLfNCO-H- -=t OLfNVO rH CMOO-cfLfNV0C^-00 rH vo VOOCM O COCM rH HON- -cfIN- gN Opj-3-CM CM 00O oo OOCOC0C0-3- CM CO00-H- LfN N-f N— CM-cr VOOOOO-4- ovo CM OOCOO 00 LfNrHC—VOVO-Cfj ON OIN-ON-M-rH H rHCM CM OC—CD4-^OM VO CMO[>-V0OO! -H- O-3--H-C0V0-3-CM ON OCMvoi—1 H i—1rH O LTNLfN00ON-M~rH O LTN^tCMVO t— OVO-3"IN-o-LfNI ON COCM-d-LfN (MOPOVOOIACM O rHCO rH O O V v rH rH rH o o V rH H rH LfN CM IN— IN-N- CM o CM rH rH 1 -ch VO vo -cf -4- V vo $ vo O0 LfN I—I CO CM o -=J- o o VO LfN t- CM O o CM oo -3- oo I—f -d- o o V LTN o oo ON o 00 vo Lf\ 21 ON CM VO 00 i—I ON CM ir\ On 83 Figure 17. llean number of midge larvae found per square foot in the Holyoke study area during periodic canal drainages, October 1967 to October 1971. fclean number of larvae/ftz (hundreds) Sampling Dates 84 85 2. Low temperature effects on survival of larvae - laboratory: The effects of exposure of 4th instar larvae for 22 hours to a temperature of 3°F* is summarized in Table 10. No larvae survived this treatment as compared to 91$ survival in controls. No delayed re¬ covery was apparent when larvae were examined 32 hours after return to room temperature (74 ± 2°F.). Controls showed 74$ survival when examined at the end of the same time period. Hinton (i960) reported that Polypedilum variderplanki Hint, larvae survived temperatures to -270°C and Downes (1969) suggests that chironomid larvae in Arctic regions survive freezing temperatures by dehydration of tissues. Paterson and Fernando (1969) noted that G. barbipes larvae survived 100 days of freezing after an initial period of 50 days exposure to above freezing temperatures in a drained Canadian reservoir. It is important to note that the larvae in the present Holyoke study had not undergone low temperature conditioning prior to the 3°F exposure. Water temperature of their natural habitat on October.25, 1970, the day of collection, was 56°F. Considering this fact, the treatment would appear to be extreme. However, the purpose of the test was to determine if exposure to sudden freezing temperature would reduce the chances for survival of overwintering larvae. Sub¬ freezing temperatures have never been recorded in the canal habitat of the larvae and it would seem worthwhile to investigate temperature as a means of control since flow of water in the canals can be manipulated or completely excluded at any season of the year. These laboratory re¬ sults suggest that winter canal drainage may be an effective way to re¬ duce larval populations. 86 Table 10. Effects of 22 hours of low temperature on the survival of 4th instar midge larvae in the laboratory. Lot 1 - Treated. (number of larvae per inch square) Number of living Number of living Number of larvae re¬ larvae at start larvae after 22 hrs covering after re¬ of tests at 3°F. turn to 74° for 32 hrs 11 0 0 8 0 0 7 0 0 6 0 0 5 0 0 8 0 0 7 0 0 10 0 0 9 0 0 9 0 0 Total 8o 0 0 Mean 8 Lot 2 - Controls (number of larvae per inch square) Number of living Number of living Number of larvae larvae at start larvae after 24 hrs surviving after 32 of tests at 7l+°P. additional hours IT 8 7 6 6 5 9 8 5 4 3 3 10 7 6 5 5 4 3 3 2 9 9 8 8 7 7 7 7 4 Total 69 "r 63_ 51 Mean 6.9 - 5.1 87 D. Laboratory Insecticide Studies, A search of the literature revealed no previous laboratory studies •with midges on the effects of the emulsifiable concentrate formulations tested here. 1- Efess: Eggs were exposed for 51*5 hours in solutions of 1 ppm Abate, malathion and Naled. The results of these treatments are found in Table 11 and Figure 18. Analysis of variance based on per cent hatch trans¬ formed to arc sine values revealed highly significant differences be¬ tween treatments at the 95$ probability level. Controls were utilized in all experimental schemes, but were not included in the statistical analysis. All treatments and controls were randomized. Controls showed 100$ hatch as compared with malathion at 98$, Abate at 50$ and Waled at 34$. This data suggests that malathion is quite ineffective for pre¬ vention of egg hatch. In only one test did any depression of hatching occur. In additional tests of malathion at a concentration of 10 ppm no hatching occurred at the end of 35 hours. Accompanying controls showed 82$ hatching. Both Abate and Waled effectively reduced hatching at the 1 ppm concentration. No additional tests on these two agents were made. Rabon was tested under similar conditions, but for 43 hours expo¬ sure at concentrations of 1, 10, and 1000 ppm (Table 12). Analysis of variance showed a highly significant difference between treatments. Controls were not included in the statistical analysis. Raton was the least effective insecticide in the prevention of egg hatch. At 88 Table 11. Effects of 1 ppm Abate, malathion and Naled on the hatching of midge eggs at the end of 51.5 hours exposure. ABATE MALATHION NALED CONTROLS 1 l8 1 5.5 16 16 100.0 23 1 4.4 12 12 100,.0 2 19 6 31.6 14 14 100.0 18 3 16.7 9 9 100,,0 3 21 16 76.2 12 12 100.0 16 5 31.3 10 10 100, .0 4 17 7 41.2 9 9 100.0 9 3 33.3 16 16 100, .0 5 15 11 73.3 12 12 100.0 12 2 16.7 l4 14 100,,0 6 28 1 4.4 15 15 100.0 11 4 36»4 7 15 11 73.3 13 13 100.0 13 7 53.9 8 17 14 82.4 9 9 100.0 11 9 81.8 9 9 7 77.8 18 15 83.3 15 10 66.7 10 10 10 100.0 13 13 100.0 14 4 28.6 Total 169 84 131 128 142 48 61 61 Mean jo hatch_£0!l__IQOyo Figure 18. Effects of 1 ppm Abate, malathion and Naled on the hatching of midge eggs at the end of $1.5 hours of exposure. 89 i. ■ • i '' ■ 1 • . ' • i \ i 90 Table 12. Effects of 1, 10 and 1000 ppm Rabon on the hatching of midge eggs at the end of 43 hours of exposure. rabon rabon rabon controls 1 ppm 10 PPM 1000 PPM to to I to CQ Pi 3 M 1 £ a . oo oo oo on -d* -cb -rh -d- r~1 • • • • • P • • • Pi p Ph Pi 0 o o 0 0 O O 0 O o 0 O o Pi 525 Pi S3 Pi P3 S3 Pi 52! P3 1 "TT £T 100.0 i4 i4 100.0 13 0 0.0 12 12 100,,0 2 22 22 100.0 15 14 93.3 11 0 0.0 21 21 100,,0 3 11 11 100.0 15 15 100.0 9 0 0.0 22 22 100,,0 4 l6 16 100.0 9 9 100.0 11 0 0.0 16 16 100.,0 5 • 13 13 100.0 9 9 100.0 16 0 0.0 16 16 100,,0 6 6 6 100.0 16 l6 100.0 7 0 0.0 10 10 100,,0 7 20 20 100.0 11 11 100.0 19 0 0.0 8 22 22 100.0 12 12 100.0 19 0 0.0 9 15 15 100.0 24 23 95.8 30 0 0.0 10 14 14 100.0 8 8 100.0 16 0 0.0 Total 147 147 133 131 151 0 97 97 Mean hatch_100$22h_2$iqq$ 91 concentrations of 1 and 10 ppm hatch was 100$ and 99$ respectively. At 1000 ppm no hatching occurred. Further tests of intermediate concentra- tions were not made in this study. 2. Larvae; Tests were conducted on 1st instar larvae. The effects of 1 ana 10 ppm concentrations of Abate, malathion and Naled on larvae at the end of 4 hours exposure to 1 ppm and various time exposures to 10 ppm are shewn in Tables 13 and 14. Analysis of variance based on $ kill transfored to arc sine values revealed highly significant difierences between treatments at the 99$ probability level for both concentra¬ tions. Controls were not statistically analyzed. A comparison of per cent mortality in controls (9$) versus Abate (4$) and malathion (2$) treatments at the 1 ppm concentration suggests ineffectiveness of these insecticides. Naled at 1 ppm resulted in 1 8$ kill, making it the most effective agent of the three tested at this concentration. At 10 ppm all three insecticide treatments reflected much higher mortalities (Abate 60$, malathion 93$> Naled 48$) as compared with controls (9$). Hiese results imply that malathion, in particular, is effective at 10 ppm under laboratory conditions on 1st instar larvae. Field collected larvae in the 2nd and 3rd instar in tubes on acetate inch squares were treated in the laboratory to a single im¬ mersion in a solution of 1000 ppm of Abate, malathion, or Naled. See Table 15 for results of these treatments. Analysis of variance revealed a significant difference between treatments at the 95$ probability level. Percentage kill was Abate 34$, malathion 95$, and Naled 71$ as 92 Table 13. Effects of 1 ppm Abate, malathion, and Naled on 1st instar niidge larvae at the end of 4 hours of exposure in the laboratory. ABATE MALATHION NALED CONTROLS 1 PPM 1 PPM 1 PPM 01 cn 01 U1 p P P a ft ft U1 P P P P 0 O -zt- O o O p •rH •H •H •H -P *H -P *H -P P CfH cd o cd O cd O cd o o o o o •H •H H3 •H 'd td rH P rH p rH p P ft i> P > > ft > > ft > f> P cd P •H P P •H P P •H P P •H P o cd rH CD cd rH 0 cd rH 0 cd rH 0 •H •—l Cd O rH cd O rH cd O rH Cd O rH ft • • • • p • • P O 0 0 0 0 0 h9 sg O Per ft IP rs-r £5 £ ft ip Per £ IP ft 1 24 22 8.4 23 22 4.4 25 24 4.0 27 27 0.0 2 24 11.1 27 15 15 0.0 14 14 0.0 22 22 0.0 3 27 26 3.7 36 36 0.0 6 3 50.0 17 17 0.0 4 9 9 0.0 6 6 0.0 20 17 15.0 9 9 0.0 5 14 14 0.0 9 9 0.0 8 5 37.5 9 7 22.2 6 31 30 3.2 12 11 8.3 14 10 28.6 10 9 10.0 7 28 28 0.0 8 8 0.0 6 4 33.3 8 20 20 0.0 30 29 3.3 9 7 22.2 10 10.0 10 10 0.0 8 12.5 Total 190 182 1^9 146 90 71 94 91 Mean Kill Figure 19* Effects of 1 ppm Abate, malathion and Naled on the survival of first instar midge larvae at the end of b hours of exposure. oC ' \ 100 :] 95 i 90 — 05 >_ ti> 30 . i 75 — 70 ,1 i • . 05 60 i 55 50 - .tt (. • * 45 cent 1 1 o 40 Ci. r c (VI i ' I ; ■ • • !■ • 30 — S ■ I i 25 - 20 —■ 15 10 L 5 - i o L Abate Malathion Naled Control Treatment it, - .1i 94 Table 14. Effects of 10 ppm Abate, ma lath ion, and Naled on 1st instar midge larvae after various time exposures. Abate Malathion Naled Controls 10 PPM 10 PPM 10 PPM w 03 d 03 03 ,d iJ •P il 03 d oo d d d 0 o OJ o C— o oj O -P •H •H •H •H -P «H -P «H -p 1 6 3 50.0 13 0 100.0 7 4 42.9 8 6 0 .0 2 11 5 54.5 8 0 100.0 10 9 10.0 9 8 11 .1 3 12 l 91.7 7 2 71.4 11 2 81.8 6 6 0 .0 4 4 2 50.0 9 0 100.0 12 6 50.0 7 7 0 .0 5 9 5 44.4 7 0 100.0 13 13 0 .0 6 10 15 33-3 16 4 75.o 23 17 26 .1 4 l 7 75-0 7 0 100.0 13 13 0 .0 8 10 l 90.0 5 0 100.0 9 2 l 50.0 5 0 100.0 10 10 0 100.0 Total r 73 29 87 6 40 21 79 72 Mean °/o Kill 6ofo b&jj Figure 20, Effects of 10 ppm Abate, malathion and Naled on the survival of first instar midge larvae at the end of various indicated time exposures • ' J. ' i Treatment i 96 Table 15. Effects of 1000 ppm Abate, malathion and Naled on field collected 2nd and 3rd instar midge larvae in tubes on acetate samplers at the end of 2 hours after treatment. Abate Malathion Naled Controls 1000 PPM 1000 PPM 1000 PPM CO CO CO CO d d P 4d M d d d d O OJ 0 OJ • 0 OJ 0 OJ •rH •H •H •H 43 1 13 12 7.7 6 0 100.0 TT 8 0.0 10 10 0,,0 2 5 2 60.0 12 0 100.0 20 0 100.0 19 19 0..0 3 11 9 18.2 6 0 100.0 4 4 0.0 6 6 0,,0 4 20 18 10.0 14 4 71.4 5 0 100.0 5 10 7 30.0 14 1 92.9 10 0 100.0 6 4 0 100.0 10 0 100.0 12 0 100.0 i § 5 0.0 12 1 91.7 7 0 100.0 \ Total 68 6 53 74 66 12 35 35 Mean t Figure 21. Effects of 1000 ppm Abate, malathion and Naled on the survival of second and third instar midge larvae in tubes on acetate samplers at the end of 2 hours of exposure. i I! i! 100 1*7“' I 98 compared to zero mortality in controls. Considerable variation in per cent kill within each treatment was evident, but the data indicates that all treatments were somewhat effective, with malathion showing the most promise. 3. Adults: Field collected adults were exposed for 10 hours to either 0.1# Rabon or 0.1# malathion in aluminum screen cages which had been pre- treated by dipping. Two types of exposure were compared to assess the lasting effects of the insecticide treatments. Results of these tests are found in Tables 16 and 17. Analysis of variance indicated no significant differences between treatments. Controls were not in¬ cluded in the statistical analysis. Comparison of controls with treat¬ ments shows that all treatments were effective in killing adults. Rabon killed 88# and malathion killed 100# of the adults exposed to screening which had become drip-free of insecticide solution. Two days after treating the screening the agents were still effective with Rabon show¬ ing 94# kill and malathion showing 100# kill. Controls in the above experiments showed 36# and 43# mortality, respectively. Since no published studies of the insecticidal effects on midge adults of the four chemical agents tested were found, comparisons of the author’s results with those of other investigators were not made. Field Insecticide Studies on Adults. These were the first known attempts at adult midge control with malathion and Rabon. 1. Field Control: Table 16. Effects on adult midges of 10 hours of exposure to Rabon or malathion (0.1$) in small aluminum screen cages immediately after treated cages had drip-dried. Rabon Malathion Controls CO CQ CO Jj h M O O O rH i—1 I—1 d d p P p p P P o •H •H •H -P -p ft -p ft ft Cd cc3 cd cd cd cd O o o •H (U •H Total 12 0 39 Mean 100 Effects on adult midges of 10 hours of exposure to Raton Table 17• and ma lathi on (0.1$) in small aluminum cages two days after treated cages had drip-dried. 1 10 0 100.0 9 0 100.0 nr 3 62.5 2 10 0 100.0 9 0 100.0 10 4 60.0 70.0 3 10 2 80.0 12 0 100.0 10 3 4 14 0 100.0 7 0 100.0 11 10 9.1 5 11 3 72.8 9 0 100.0 12 9 25.0 6 9 0 100.0 10 0 100.0 13 9 30.8 7 11 0 100.0 9 0 100.0 8 10 0 100.0 10 0 100.0 9 8 1 87.5 9 0 100.0 10 10 0 100.0 9 0 100.0 Total 6 0 38 o Mean jo tan_2ii£ Figure 22. Effects of Rabon and malathion on adult midges at a concentration of 0.1$ when applied to the screening of small aluminum cages. Recorded as mean per cent kill at the end of 10 hours of exposure. A. Exposure to treated screening begun immediately after cages had drip-dried. B. Exposure to treated screening begun 2 days after cages had drip-dried. Mean percent kill ft abon Treatment f»«a Iathion A B A IS Control 101 102 t On seven dates between July 25 and August 8, 1970 the insecticides nialathion at a rate of 1.4 lbs. actual per 100 gallons of finished spray and Rabon at a rate of 1.0 lbs. actual per 100 gallons of finished < spray were applied to mill windows, screens, building walls and canal periphery as previously described. The results of these treatments axe shown in Tables 18 and 19. A least squares analysis of variance by V Harvey (Fortran program for unequal frequencies) was made of the data obtained using actual numbers of resting adults found in treated and untreated (control) areas. This analysis indicated highly significant differences between treatments, dates and the interaction of treatments and dates. Of the two chemical treatments, malathion demonstrated a higher level of control than Rabon, at least during the five final dates (31 July - 8 August 1970) of the tests. Midge adults were exception¬ ally numerous during this period and may have obscured the apparent ef¬ fectiveness of the malathion. It is important to note that the word "control" as used in these tests meant a failure of adult midges to alight and rest on insecticide treated screens. That kill actually oc¬ curred was demonstrated by the piles of dead adults on treated screen ledges and their absence on control screen ledges. There also very well could have been a repelling effect by the insecticides. Killing or repellancy would have achieved the goal of the control program which was exclusion of midges from building interiors. There exists much variation between resting counts made on July 25 and 29 and the remainder of the sampling dates. Light trap survey Table 18. Effects of malathion applied at a rate * of 1.4 lbs. actual per 100 gallons of mixed spray on the numbers of midge adults resting on 32 inch by 32 inch mill window screens in the Holyoke study area. a o o o 3 o H a & ft lx! •P -P to 0 0 C/3 < -p < -p H OJ ft On w 3 03 ft 0 VO 0 >» on 03 5) VO >> 2 CM CO CO (—1 CO Lf\ CO ta- CVJ CO CO CM LP\1 PS ft 0 p OnOn co coco p CMCO J-VD OP-P- CO -PCM CO LTNCMVOOft CO VOOPCM ft o o voinON O VOCOP CM CO ft VO00CM ft pO CM ftCO O CMftLTN O C—VO LTNC0 COONCOCOLTVVO CM PLf\VOftCOP CM OftOP H fOH(O LTN COfti—Ii—1 0- OnCOOPPOnCMOn00 ONCO ftVOCMOnUMOLTN ft i—1CMCO ft CO O COLTNftCM OOOOftOOPftO o ft CMCOPLTNVOt-COONO CO ft ft p 00 00 CO oo vo vo CO ft O o CM o CM LTn CO a o iH O CTn ON 1—1 i—1 rH CM ft CM rH ov ■ CO ft CM 1—1 LT\ o rH ft -p O Cj vo vo p p VO VO p CO CO vo vo o O o o o LTN O' CO ft i—1 O CM CM CM ft CM Qn CO ft LO CM l/\ n- rH CM CO CO O CO O o S cd 0 • • • 0 • • • • • . • • • • • *A total of 25 gallons of finished spray was applied to point of run-off on the screens, building faces and adjacent areas on each day prior to recording resting counts. 103 Table 19. Effects of Rabon applied at a rate * of 1.0 lbs. actual per 100 gallons of mixed spray on the numbers of midge adults resting on 32 inch by 32 inch mill window screens in the Holyoke study area. o o B o a a Q <3 -P ■P CO 0 03 records indicate that the test period included the early part of the sudden, sharp increase in adult numbers which began on July 31 (Table 2). It seems likely that this accounts for the highly significant F ratios noted for dates and interaction in the analysis above. Neither insecticide was effective in preventing midge adult entry of buildings % in August. Longevity of Malathion: Malathion was applied to brick and glass pane surfaces in a single treatment on August 5, 1970 at a rate of 1.4 lbs. actual in 25 gallons of finished spray. The results of this application measured as number of adult midges resting on brick or glass are summarized in Tables 20 and 21. Regression analyses of insecticide results on both types of sur¬ faces were plotted. Figures 23 and 24 indicate positive linear re¬ gression. Ninety-five per cent confidence intervals were calculated and in all but one case, the points in the scatter diagrams fall within these limits. This data suggests that the controlling effects of malathion last longer on glass surfaces than on brick. At the end of seven days a mean number of one adult was observed on glass versus ten prior to spraying. A mean number of seven midges was found on brick surfaces versus seven prior to spraying. However, up to three days may elapse before a noticeable increase in number of midges resting occurs. This being true, malathion treatment of -buildings on a thrice weekly basis should provide a sufficient barrier to midges attempting to enter. The Table 20. Longevity of malathion on brick surfaces. Recorded as numbers of midges resting on brick square foot surfaces. -P •p a •P P H « p •H •H CD P S3 Sh The mean number of midges resting per square foot of brick surface on the day prior to malathion application was 6.5. £iean number of midges restin Days after spraying 4 4 4 4 107 Table 21. Longevity of malathion on glass pane surfaces. Recorded as numbers of midges resting on glass pane surfaces (131.6 in^). rH ♦H <3 •H •P -P *P •p (D O P4 o P c5 to !>; U CD The mean number of midges resting per square foot of glass surface on the day prior to malathion application was 9*7* fclean number of midges resting Days after spraying 109 110 0 practicality of such a spray program from an economic point of view is questionable, however, and a chemical having a longer effective con¬ trol period should be considered. c Ill F. Mld^e Biology and Behavior. 1. Dpr,rrrl'otlon of emergence: Data pertaining to adult midge emergence vere collected during the summers of 1970 and 1971. Tables 22 through 25 summarize these find¬ ings. Adult emergence rarely occurred between the hours of o:30 A.M. and 7:30 P.M. on the dates recorded. Emergence was most common during the time from 7:30 P.M. to about 10:00 P.M. After 10:00 P.M. emergence appeared to decrease although quantitative data stipulating this vere not obtained. These findings are similar to those of Frommer and Rauch (1971) and Nielsen (1959, 1962b) who worked with other genera and species of Chironomidae. First emergence occurred when natural light reached a mean intensity of 27 foot candles based on six separate day's samples (see Table 23)* At this intensity, pupae begin to arrive at the water surface by means of thrashing motions with the paddle- shaped posterior abdomen. Upon breaking the surface film., the notum split and the fully-formed adult emerged in a mean time of 8.6 seconds (see Table 24). After freeing itself from the pupal skin, the adults flew away immediately or rested on the water surface for a short time. The cast pupal skin remained buoyant to be swept away by the surface currents. A comparison of numbers emerging in total darkness and under the influence of 26 foot candles of artivicial light revealed a positive phototaxis by unemerged adults (see Table 25). Data collected on three separate evenings indicated that from four to seven times as many adults entered emergence traps in the light as in the dark. This is the 0 P rH p P •H fp CO 0 P 0 <—< 0 bC ^ OOO LA VO oo CVI OJ 0 p •H >> g 43 r-s p •h co 0 m 0 •P P rH 0 0 *0 <•0 p p p. 0 OOOOCOCOOOOOO CO M O OOOOA A H V crt CVJ OJ CVI CVI P P A A A CO P O 1—1 bQ c 0 •H CH > t—( " P 0 P P *H 0 1—! •H 0 P t> P <0 0 —- P P IQ ooooooo ooo o P 0 OJ i—1 VO i ! rl i 1 i I i 1 i 1 i 1 •H H P rH LA LA p • p 0 rH 0 P t> D'- 0 -H OV •H g P H Eh ^ 0 •0 bO P p 0 •H hQO P t 0 CO 2S^pHp^PnP-ifMPMp-i S 1 Date Time - PM ^Illumination Water (foot candles) Temp.°F. 7 Aug 8:15 38 79 10 Aug 8:15 Ik 78 11 Aug 8:10 Ik 79 12 Aug 8:15 32 79 13 Aug 8:10 28 79 19 Aug 7:40 36 79 Mean = 27 foot candles ^Measured at a height of 3 inches above surface of canal waters. Table 24. Length of time in seconds required for the adult to free itself from the pupal skin and "become airborne. Data obtained on three separate days in the summer of 1970- Time - Seconds 7 Aug 9 Aug 11 Aug 5 6 15 4 8 9 6 4 5 9 5 10 6 10 11 7 12 9 5 7 17 12 8 11 5 4 8 9 4 11 15 12 7 b 7 12 8 6 12 9 5 5 9 5 9 10 9 8 7 13 8 10 8 10 13 17 13 9 6 7 7 7 11 5 8 10 12 11 5 6 5 9 9 10 13 Total 201 197 245 3 day mean - 8,6 seconds Tab3-e 25. Number of adult midges -which emerged per minute in artificial light or in darkness as determined "by catches in emergence traps j 197^ and 19 fl* I '^ i—i ft 1—1 ON L n ON oo CO on ft s «j-D •*H ON p ft <1 Lf\ 2 CO O P CO p ft 2 §> i go ONft ON <; ir\ ft •• CvJ 00 co On P 2 to 1 i O ftp HrP 1—1 ft o O O ft* O LT\ CVJ ft • P ft* • ft ft -P i—i ft •H •H •H •H P o ft -p p i—! •H < CVl •H •H ft O UD 2 P Vl ft c3 _ feO O cd M VO •rH < CVJ •H O ft • u ft oj -H ft P CO O • Vi VO Vi cj 1 Light VO ft CVJ' ft O ft o O O ft • ft o o CO LCNmvoLf\P p ft o ononHcvj inpoo ocnp LT\ I—VOCOft cvj cn P rlOJp vo cvjpCNft-on cvj cnonft-volcn VO LCNP p LTNft- oPCVJ on pcoltno VO ft- co CO p p p ON cn CVJ vo CVJ p LT\ p P EH o C5 vo p p on CVJ on p cn ON £ on o\ p I—l cvi S sd 0) c5 ft p ft .p p> ft -p •H -p •H -P •H -P ft P-« ft -P fti ft ft -P O Vi a o o /—t 2 O 2 o ft Vi 0 0 2 sd ft ^ U2 0 0 to 2 W 2 _ O c-1 •H Vi ft 0 O 0 ft -P Vi •H CO o ft Vig O Vi 0 £ ft 2 CO 2 * P *H firsts known report of such behavior in the Chironomidae. 2. Description of swarming: Swarming occurred twice daily at dawn and dusk. Observations were made of a number of physical factors which mignt affect swarming be¬ havior (Table 26). The most consistent factor of those measured which could be correlated with this activity was the mean number of foot candles of light at which time organized swarming took place. For dawn swarms this was 9.3 foot candles and for dusk swarms it was 6.2 foot candles. This data strongly suggests that the triggering device which initiated swarming was light intensity. Nielsen and Greve (1950) re¬ ported that 7 Lux (O.65 foot candles) illumination initiated and dis¬ persed a mixed swarm of Aedes cantans and Chironomus plumosus. They also reported that humidity was of minor importance and that low temper atures may delay swarming. No swarming occurred below 50°^• Dusk swarms: Swarming began with short flights of males in small groups of 4 or 5 or even singly. These flights were typical of later swarming in that the insect flew in a "box” pattern covering an air space of perhaps one square foot, forward, to the rear, up and down, and often diagonally across the box. Syrjamaki (1965) describes this activity as ”pre- swarming." Light intensity during these flights was recorded at l40 - 150 foot candles. Small groups clumped together in an irregular hovering pattern which returned to the box pattern periodically. As light intensity diminished, an irregular pattern developed during which activity was 117 Table 2o. Physical factors recorded at time of organized swarming of midges. . V jjabiv uwcuuj O * Light Wind Temp Relative Intensity Op Date Time Speed Humidity in Foot mph per cent Candles 8-04-70 8:35PM none 72 65 6 8-05-70 8:15PM 8-12 72 74 5-6 8-07-70 8:20PM none 73 77 6-7 8-08-70 8:20PM none 72 81 6 8-10-70 8:15PM none 78 51 5-6 8-11-70 8:10PM 5-8 72 57 6-7 8-12-70 8:08PM none 78 70 6 8-13-70 8:13PM none 80 64 4-5 8-19-70 8:00PM 13-18 77 50 5-6 9-10-70 7:25PM 8-12 74 90 10 Mea n light intensity = 6.2 f.c. Dawn Swarms: 8-09-70 5:30AM 2-3 62 90 6 8-12-70 5:4-5AM 0-2 64 90 20 8-13-70 5:35AM none 66 86 r - 7 8-14-70 5:40AM none 05 95 6-7 8-18-71 5:42AM none 65 86 7 Mean light intensity = 9-3 f.c. 118 increased by members of the swarm which often increased to 25 - 50 so¬ bers. This pattern was characterized by a lack of direction and rapid flying. At a mean light intensity of 6.2 foot candles the swarm, now grown to many members by the joining of many small swarms or, in some cases, remaining as a small swarm, began an "organized" pattern. This pat¬ tern was characterized by all members flying forward and backward in essentially one direction, but changing altitude and position in the swarm. Some members flew in opposite or oblique directions, but the appearance of the swarm was that the vast majority were facing in the same direction. Slowly, altitude was gained and the swarm often rose to 50 feet or more off the ground. Massive swarms of thousands often oriented themselves above trees, buildings, or other structures. These great swarms usually resembled columns of smoke against the setting sun and could be heard by an observer standing beneath the swarm. . Not all swarms rose. Some remained 6 to 25 feet above the ground orienting on objects such as bridges, autos, and humans. It was not unusual to have a swarm of several hundred midges orient at head height to several feet above the head of the observer. These "low" swarms would regroup de¬ spite collecting efforts of the investigator. On several occasions swarms developed above the raised tailgate of a station wagon. If the auto was then moved at a speed of 10 mph to a site 50 feet away, the entire swarm moved to the new site and continued orienting abc tailgate. Downes (1969) describes this phenomenon well as "the swarm seems indeed to be merely a special case dominated by a relatively 119 rare "but strongly preferred feature of the landscape." (p* 2(u). Samples of the composition of the dusk swarms were taxen liable 27)• Results of sweepings at the 6-7 foot height always indicated fcnau G. lohiferus was the only species present. Nielsen and Greve (19re¬ port mixed swarms of Chironomus plumosus and Aedes cantans and Chiang (1963) working with Cecidomyiidae recorded Anarete johnsonii (Felt) and . a closely related form swarming simultaneously. Downes (1969), how¬ ever, suggests that such mixing is rare. Males were the only sex in these swarms. Gibson (19^5) attributes this masculinity to the fact that any females which originally may have been present have mated and flown off. Although swarms flew in such tight formation that occasional contact occurred, no attempts at copulation were made between males. Contact appeared to generate an avoidance reaction and both males rapidly flew to separate areas of the swarm. Downes (1969) states that the culiciformes do not exhibit darting behavior between males in swarms, but this study suggests that such behavior does exist and that contact somehow releases the male from the pattern. Dawn swarms: Dawn swarming followed a similar pattern sequence to the dusk swarm¬ ing, but was of shorter duration in the initial patterns. A mean light intensity of 9.3 foot candles stimulated swarming and an organized pat¬ tern was achieved almost immediately. At 50 - 60 foot candies swarms ■were 25 feet above the ground. Mating occurred at 60 to 180 foot candles. Swarms became disorganized at 260 - 270 foot candles. At a light intensity of 380 foot candles the swarms had dispersed. On one 120 Table 27. Samples taken in the summer of 1970 small,, organized midge swarms at dusk. Counts recorded as number per sweep. All sweeps taken at six feet above ground level. Only males were collected. Aug 7 Aug 8 Aug 10 Aug 11 Aug 12 12* 6 2 6 7 *3 15 3 0 2 5 7 3 8 1 2 9 2 5 3 2 10 3 8 1 3 11 5 6 5 4 12 3 4 4 5 9 6 4 7 7 5 3 3 2 1 10 4 5 2 2 Total 100 38 48 33 38 Mean = 5.14 midges ^Actual number of midges collected per sweep with a transparent cup 4.8 cm in diameter and 4.4 cm deep. 121 occasion swarms dispersed at 180 foot candles. Dawn swarms were noo sampled for composition. 3. Description of mating: Observations of mating in swarms were made at dawn only. Dark¬ ness precluded observation during the evening swarming. Mating occur¬ red at light intensities "between 60 and 180 foot candles and one owarms observed were at a height of 10 to 20 feet. Accurate observation Oi mating above this height was impossible. Most members of the swarm flew in the organized pattern as previously described. Mating occurred when a female entered the swarm from below and was seized by a male. Coupling involved the attachment of the male claspers to the female's posterior abdominal segments in some fashion yet to be described. Coupled pairs slowly descended from the swarm, maintaining a horizontal plane in flight. The only site of attachment was the tips of the abdomen, the remainder of each body assuming what appears to be a nor¬ mal flight position, each member facing in an opposite direction. Mean time for copulation was 6.07 seconds. Pairs separated at a mean height of H.51 feet above the ground (see Table 28 for mating data). Downes (1969), in reviewing the data of others, states that mating often oc¬ curs within a few seconds and that separation occurs prior to reaching the ground. After separation, females flew away from the swarm, presumably to resting sites. Males reentered the swarm. It was impossible to observe whether these males mated again because of the intense activity in the swarms. 122 Table 28. Mating of midges. Length of time of copulation and height above the ground at separation of pairs. Copulation Separation (Height above Pair (Duration in sec.) the ground in feet) 1 .. 6 10 2 4 15 3 5 6 4 5 ' 6 5 10 8 6 6 8 7 5 15 8 8 10 9 7 12 10 5 12 11 5 15 12 10 10 13 6 10 14 5 12 15 8 12 16 6 15 1? 5 12 18 7 10 19 8 10 20 5 15 21 7l 10 22 7 8 23 7 12 24 8 12 25 6 8 26 5 12 27 7 12 28 6 12 29 5 15 30 6 10 31 6 15 32 3 12 33 3 20 34 6 12 35 5 12 36 5 10 37 5 10 38 5 12 39 4 15 40 6 15 41 5 10 42 12 3 43 6 15 44 8 8 ^5 4 15 Total 273 Total 518 _Mean = 6.07 seconds_ Mean = 11.51 feet 123 Mating also occurred "between newly emerged virgin females and low- flying males after dark. On five different evenings "between 9 and 10 P.M. this type of mating was observed "by means of flashlight illumina¬ tion. Virgin females, standing on the water surface or not yet free of the pupal skin were approached from "behind and mounted by males flying alone in an undirected fashion some 6 to 12 inches above the canal waters. Nielsen (1959) reports that males mount from behind in G. paripes at rest. Attachment of abdominal tips was achieved rapidly, the female often becoming airborne upon contact with the male. Airborne pairs descended, often landing on the water surface before separating. These matings often occurred in one second or less. After separation, males attempted to copulate with other females. Females were not observed in a second copulation. A number of the coupled pairs were collected from the water surface ana returned to tne laboratory for observation. These results are sum¬ marized in Table 29 and indicate the following: -L. Females may oe lertilized by males immediately after emergence. 2. Fertile eggs may be laid within 24 hours after mating. The above observations are the first known for G. lobiferus. 3. These eggs may hatch at the end of 3 days. Thus, within 4 days after emergence, progeny of this species of midge may be reestablished in the tube environment under water. This suggests that control proce¬ dures directed against both the egg and adult stage must be carefully timed and of sufficient frequency to ensure contact within successive life cycles. Table 29. Mating data, egg laying and hatching data and longevity of selected midge pairs. 1971* * I ft ft & ft •p -p ft -P ft ft -P •H rd •P ft •H ft rd CD 0 0 to tO CD CD 0 £ CD to-p 0) 03 to to CD CD CD' crj ft CD P <0 CD a c3 Ctf o3 ='h^ ft •H ■ft ft ft ft ft ft ft i—1 M ft ft ft CD {ft O 0 0 a O 0 0 CD o3 s CT) CD P O CD O 0 «—4 pj {ft P 0 —J VO ■ ft ft l—i ft O ft ft on ft- ft ft ft LTN 1—1 ft O CO •• ft ON —u CO •* ft 2 to P MS P {ft p {ft p P ft fcOS {ft CO CO -ft VO 00 ft ft ft ft O ft ft ON D— CO •• 1—1 ft ft 0 1—l ft ft ON 00 •• C\J P {ft 2 {ft P P-< tos p 2 P-* tpS to P {ft OO CO -4- •• 00 -ft •• CO ft ft ft LTN LT\ ft ft ft ON ft ft ft LTN ft ft ft ON D— OO to MS p P Ph to P £*» tos to p to CO CO ft“ •* CO ft •• ft ft 1—1 LTN ft ft ON ft LTN ft ft LTN ft ft ft ON ft- 1—! ft ON p to p P-1 to s p to 3 P P^ tos to to CO CO VO CO ft IjCN ft ft ON ft ft LTN *• ft ft 0 ON ft ON ft LTN •• ft 1—i 0 CM LTN p P-1 tos p to p P Ph tos to P t0 3 to ft CO 124 125 Females are shorter lived than males. In these studies, females lived an average of 2.8 days after emergence, while males lived an aver* ge of 4.1 days after copulation. Fellton (1940) records males as living nine days from time of emergence. Kb attempt was made in this study to determine the age of males at mating. 4. Description of oviposltion: All observations in this study were made after dark under flashlight illumination between the hours of 9 and 10 P.M. on 5 different nights. Females ready to oviposit usually took up a position on a moist vertical or near-vertical surface near the water surface. Ko females were ob¬ served selecting dry surfaces. The oviposition attitude began with a waggling and rotary movement of the posterior abdomen. The metathoracic legs were raised and the abdomen was stroked by the tibiae, the weight of the body shifting onto the messo- and prothoracic legs. Eggs were extruded as a curved dense mass 3 to 5 mm long (mean of 10 samples was 3.6 mm) onto the posterior surfaces of the metathoracic tibiae which were now held horizontally just below the female opening and, in this position, served as a receiving platform. Fischer (1969) describes a similar pattern of egg extrusion for C. nuditarsis Str. After egg de¬ position, the female made a post-oviposition flight. Eggs were usually released during this flight either by dipping the metathoracic legs in the water, as recorded by Grodhaus (1963b), or by simply dropping the egg mass. Nielsen (1962a) observed that G. paripes females dipped the tip of the abdomen in water while in flight to lay eggs. This behavior is probably the equivalent of dipping the legs. Egg masses were found 126 in large numbers on damp rocks and wood as well as on light trap and ad¬ hesive trap surfaces up to 8 feet away from any moiso surxace. n^gs also were deposited in collecting vessels and cages where no water existed. No females were collected hearing eggs on the tibiae after the post-oviposition flight. The time required for egg laying was 6.09 minutes (mean of 11 observations - see Table 30)• Egg mass enlargement: Egg masses enlarged by taking in water when deposited on a moist surface. A size of 10 - 20 mm may be reached as determined by 10 obser¬ vations of masses in the study area (Table 3l)» In the enlarged state the eggs were enclosed by a sticky gelatinous matrix described previ¬ ously by various authors. The number of eggs per mass averaged 1500 based on actual counts of 5 egg masses. Newly laid egg masses sink in water, but may attach readily to any floating or submerged structure by means of a long, slender suspensory stalk or the gelatinous matrix. The stalk may stretch to 18 inches or more. This data generally supports the findings of Morrow, et al. (1968) and Sturgess and Goulding (1969) for other genera and species of Chironomidae. Computation of the sizes of egg masses and the time periods re¬ quired for masses to reach maximum size were made. Females in the egg extrusion attitude were collected in culture jars containing a small amount of water. These females did not attempt to fly and could easily be scooped into the jar. Jars without water were used to contain other females which proceeded to deposit eggs on the sides and bottom of the container. These masses were measured and the results recorded in Table 30. Time required from the beginning of the female ovi- position attitude to the post-oviposition flight in the field. Time in Female Seconds A 315 B 400 C 360 D 305 E 378 F 413 G 428 H 347 I 415 J 307 K 356 Mean time ; 365*5 seconds or 6.09 minutes 128 Table 31. Egg mass sizes at the time of egg extrusion by the female, maximum size of egg mass, after absorbing water, and mini¬ mum length of time required to reach maximum size. Sizes of egg Maximum size of Minimum length of mas s extruded egg mass after time required to (m.m.) absorbing water reach maximum size (m.m.) (minutes) 4 15 28 3 11 25 3 13 35 3 11 38 4 11 30 3 15 23 3 14 30 4 13 29 5 20 35 4 12 31 Total 36 135 304 Mean 3.6 13.5 30.4 129 Table 31 • The egg masses deposited in jars containing water were meas¬ ured several times during the enlargement period. The maximum sizes oi egg masses and minimum length of time required to reach these sizes were recorded in Table 31 • 5. Midge larvae studies with acetate samplers : Acetate faced wooden square foot samplers (Figure 7) were exposed to canal waters at a depth of 6 - 12 inches in order to study the micro- habitat of midge larvae. These investigations took place during the summers of 1970 and 1971 in the Holyoke and South Hadley study areas. Results are summarized in Tables 32 and 33. Physical and chemical variables including water temperature, dissolved oxygen, per cent oxygen saturation, pH, and turbidity are reported in Tables 3^ and 35 in the Appendix. After only one day's exposure to South Hadley canal waters in 1970, the crustaceans Cyprodopsis sp. and Sida sp. were found on the acetate surface. Both of these are transient, free-swimming forms and appeared to use the surface for either food or shelter purposes. At the end of 5 days exposure (South Hadley, 1971), midge larvae -were found on the surface of samplers and had completed construction of several tubes. xn the observations at the end of 10 and 12 days1 exposure (1970 and I971) it was noted that there were far more tubes constructed than were actually occupied. Laboratory observations of first instar larvae revealed a similar propensity for larvae to build many tubes. Moreover, larvae exchanged tubes regularly under laboratory conditions suggesting i-hat in uhis instar they are highly transitory and planktonic. Oliver (1971) reports planktonic behavior in first instar larvae until a 130 suitable habitat is found. Later instars were rarely observed leaving their tubes except when exploring the area in the immediate vicinity of the tube for food. The reasons for this excess tube building are un¬ known ^ although it may prepare the substrate for more successful and elaborate tube building by the development of a rugose surface. This may serve as an attractant (through a build up of phytoplankton and detritus) for exploring first instar larvae of the same or a later generation. Hilsenhoff (1966) reports that the first instar is photo¬ positive. This behavior pattern may explain the activity of these larvae. Photopositive reactions ot the larvae were not examined in this study, however. Massive mats of tubes, not all occupied, in excess of one inch thick have been found adhering to rock canal walls and on the bottom of canals in the Holyoke study area. These may be the work of overlapping generations rather than excessive tube building by a single generation of later instar larvae. Also present at the end of 10 and 12 days were the same crustacean species, noted above, a cyclops specimen, an unidentified pupa of Diptera, and annelid worms (Lais sp.) burrowing through the debris on the sampler. An unmeasured quantity of green algae, sand grains and organic debris composed the remainder of the material present. Samplers exposed for longer than 12 days bore a similar appearance although the animal life varied in numbers and species. At the end of 15 days exposure both midge larvae (1970 and 1971) and crustaceans (1970) were well established. In addition, annelids and the eggs of the snail (Anicola sp.) were found in small numbers. 131 The 2b day exposure in 1970 occurred early in the season (May 16 to June 9) and perhaps because of this, feu larvae were found, Many snail eggs, annelids and mayfly naiads were present. In 1971> the 2b day exposure occurred from July 21 to August 1^- and midges were more numerous. Large numbers of larvae were found at the end of 3J days exposure. Chrprodonsis sp. were present in moderate numbers, as were annelids and a single specimen of Hydra sp. which had attached to the debris. The samples taken after 51 and 57 days exposure were obtained early in the summer prior to July 6 and yielded few to many midge larvae and none to moderate numbers of crustaceans and snails. Cyclops, a mayfly naiad, and Hydra sp. specimens were also found. The data reported for ail of the exposure period above is meager at best, but does suggest that new habitats may be rather quickly colonized by larvae building many tubes often in excess of the number of larvae actually present on the surface. The tubes may prepare the surface for more successful tube building or to attract other larvae. A number of organisms live in association with the larvae, but their roles were not ascertained in this study. Table 32. Numbers of selected aquatic animals achering to acetate - faced wood samplers of the one foot depth during the summer of 1970. Each replication = one square inch of acetate O 0 Cd (D rH d rH 02 *d> ,p o i—! 02 <; & PH •H d •p CO ■p .a rH CO d O -P rd a o o o £ O 0 0 S3 CM CM ft ft -=3* CM CO ft ft 0 0 ft < >> Cj ft CD ft CQ CQ 0 a to 10 tiG CQ CQ CQ CQ CQ CQ tiO ■0 CO CD 0 to to to to to to to to 0 CD CD ft to to to to to to 0 to tO-WMO to ft taD to tO S3 bO ’ 0 0 0 0 0‘ 0 t- 0 0 0 0 0 CM r $> r*i ft «N r CQ o 00 CO CO VO o 0 -I CM 1—i I—i CO rl OJ H H H H fft (D ft ft "0 r-' ft ft 0 0 o ♦H *H Oj t§ 0 0 0 to ft ft ft I to I 0 !>■} ftj >5 i—i i—I i—I i—! 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SUMMARY AMD CONCLUSIONS Adult midge surveys "based on "black light trap data lor two sum¬ mers indicate that nuisance levels of midges may "be expected within the period from early June through mid-September with peak numbers most likely during July and August. The survey also points out that the Holyoke canals are the main source of adult midges creating summer nuisances for adjacent paper mills. Factors promoting midge abundance, however, appear to be present in both the canal environment and in the Connecticut River which flows nearby. The possibility cannot be excluded that adult and immature midge immigrations from the river into the canal may reestablish midge populations and amplify the nuisance. Numbers of midges alighting on mill window screens appear to be in direct relation to the numbers emerging from the canals. Midge flight occurs at both dawn and dusk and adults are strongly attracted to light after dark. Adults in the pre-emergence stage are also strongly attracted to light at least during the period from sunset to 11 P.M. Therefore, reduction of exterior mill illumination and proper screening of all mill portals would contribute to lessening the nuisance effects of the adult midges. Most midge egg masses are located in the upper two feet of canal waters and adhere to the canal wall and various obstructions. Here they are particularly vulnerable to stranding by lowering the canal water level. Control, therefore, by desoication and/or other mechani¬ cal treatment such as heat may he a fruitful approach. Descication for as short a period as one hour in the laboratory and Ik hours in the 137 138 field was effective in reducing egg hatch. Heat treatment of egg masses for 10 seconds in the field prevented egg hatch. Although malathion at a concentration of 10 ppm prevented egg hatching in the laboratory., field studies with this agent were not suc¬ cessful at the rate tested. Laboratory tests on eggs with Abate, malathion, Haled and Rabon revealed that Haled was most effective in preventing hatch at the 1 ppm concentration. Laboratory tests on 1st instar midge larvae with Abate, malathion and Haled showed that the latter was most effective at the 1 ppm level, but that mortality was only 22$. At 10 ppm malathion was highly ef¬ fective and produced a mortality rate of 93$• Laboratory tests on 2nd and 3^d instar larvae within tubes using malathion and Haled at 1000 ppm resulted in effective control. Laboratory exposure to freezing (3°F) was wholly effective in killing 4th instar larvae. Despite this laboratory success with malathion, summer and spring treatments in localized areas of the drained canals did not effectively reduce numbers of larvae developing later in the same season. This in¬ effectiveness may have been more apparent than real in that larvae de¬ veloping later in the season may have been the progeny of immigrating females rather than larvae that survived the insecticide treatment. Under laboratory conditions adult midges exposed in screen cages treated with either 0.1$ Rabon or 0.1$ malathion experienced high mortality even when two days had elapsed between cage treatment and midge exposure. Field insecticide studies with Rabon revealed that 139 this agent was ineffective in reducing midge adult numbers resting on mill window screens. Malathion, however, appeared to he effective at the concentration tested except in the latter days of the treatment period. A major factor influencing these field tests was the sudden emergence of high numbers of adults at the same time the tests were con¬ ducted. Malathion also had an effective longevity of 3 days on brick surfaces and 7 days on glass surfaces as measured by numbers of midges resting on these substrata. The evidence pertaining to survey and control presented above sug¬ gests the following: 1. Mechanical control by means of dessication, heat, cold or all three is effective in reducing numbers of midge eggs and larvae. Thus, draining canals in winter, fluctuation of water level in other seasons and incineration of egg masses should be further investigated. 2. Chemical control with malathion at a rate of 1.4 lbs. actual per 100 gallons of spray on a thrice weekly basis as a spot treatment of window screens and mill portals is effective in excluding midge adults except during periods of massive emergences. 3» Screening of mill portals and control of exterior illumination at night to reduce adult attraction to lights would effec¬ tively supplement these control measures. Data obtained concerning the biology and behavior of G. lobiferus corroborates and enlarges upon information gathered by other 140 investigators (Felffcon, 19^0; Nielsen, 1959^ 1962; Grodhaus, 1963a; Sturgess and Goulding, 1969; Downes 1969; Oliver 1971) on other genera and species of Chironomidae. New information obtained for G. lobiferus includes: 1. Adult emergence occurs mainly in the period from sunset to 10 P.M. 2. The process of adult extrication from the pupal skin and initial flight is a rapid one occurring in a mean time of 8.6 seconds. 3. Adults are attracted to a light intensity of 26 foot candles even when still enclosed in the pupal skin. After emergence, accj.acuion go booh slacK and yellow light is pronounced. 4. nwarming occurs daily at dusk and dawn. Dusk swarms consist entirely of males except when a female enters the swarm for mating. Swarming appears to be triggered by light intensity. Ax xer initial grouping phases near the ground, the males reach an organized swarm at a mean light intensity of 6.2 - 9.3 foot candles and usually rise to a height of $0 or more feet above the ground in a dense cloud. 5. Mating may occur in the dawn swarm and lasts about 6 seconds. Maying may also occur after dark as virgin females emerge from one pupal skins. This post-emergence mating may last only 1 second and viable eggs have been oviposited by the females the day after mating. 6. Oviposition by females was observed after dark and occurred in 141 a mean time of 6 minutes from onset of oviposition attitude to postoviposition flight. 7. Egg masses are usually deposited on a moist surface or in water and measure 3.6 mm in mean length when extruded by the female. After approximately 30 minutes of enlargement by uptake of water they reach a mean length of 13*5 8. The eggs hatch in 3 days at a laboratory temperature of 72- 7o°F. 9. Ovipositing females die 2 to 3 days after mating; males die 3 to 5 days after mating. 10. Field studies made with acetate samplers suggest that new habitats may be invaded by midge larvae within 5 days. Few invasions are characterized by excessive tube building by larvae and the accumulation of debris. Concurrently, other fauna, particularly crustaceans and snails may occupy the habitat. These data suggest that chemical control measures against the adult ■s stage should be timed so as to ensure maximum contact at dusk and at dawn when the midge is most vulnerable to exposure. Control of lighting patterns after dark in and around buildings so that emerging adults would not be attracted into the mill areas would help in reducing the nuisance. y II. LITERATURE CITED Anderson, L. D. and A. A. Ingram, i960. 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Anderson. 1968. Descriptions and key to egg masses of some aquatic midges in southern California (Diptera: Chironomidae). Calif. Vector Views 15: 99-108. Mundie, J. H. 1957* The ecology of chironomidae in storage reservoirs. Trans. Roy. Entomol. Soc. London 109:149-232. Needham, J. G. and P. R. Needham. 1962. A Guide to the Study of Fresh¬ water Biology, Holden-Day Inc., San Francisco. 108 p. Nielsen, E. T. and H. Greve. 195C. Studies on the swarming habits of mosquitoes and other Nematocera. Bull. Entomol. Res. 4l: 227-58. Nielsen, T. T. 1959. Copulation in Glyptotendipes paripes Edwards. Nature. 184:1252-3. 147 . 1962a. Contributions to the ethology of^Glyptotendipes_ (Phytotendipes) paripes Edvards, Oikos 13:48-75. 1962b. A note on the control of the chironomid^ ^ ^ Glyptotendipes paripes Edvards. Mosquito Nevs 22.114-5* Oliver, D. R. 1971. Life history of the Chironomidae. Annu. Rev. of Entomol. 16:211-30. Paterson, C. G. and C. H.-Fernando. 1969. The effect of vinter drainage on reservoir benthic fauna. Can. J. Zool. 47:509-95* Ping, C* 193-7. Observations on Chironomus decorus Johannsen. Can. Entomol. 49:418-26. Reiss, F. 1968. Okologische und systematische Untersuchungen an Chironomiden des Bodensees (in German, English summary) Arch. Hydrobiol. 64:176-323* Roback, S. S. 1957. The immature tendipedids of the Philadelphia area (Diptera: Tendipedidae). Acad. Natur. Sci. Philadelphia Monogr. 9, 152 p. Sadler, W. 0. 1935. Biology of the midge Chironomus tentans Fabricius, and methods for its propagation. Cornell Univ. Agr. Exp. Sta. Mem. 173> 25 p* Steinhaus, E. A. and F. J. Brinley. 1957* Some relationships betveen bacteria and certain sevage-inhabiting insects. Mosquito Nevs 17:299-302. Sturgess, B. T. and R. L. Goulding. 1969* Species of Chironomidae recovered from three Oregon stabilization lagoons. Calif. Vectors Vievs l6(l):10-3. Sublette, J. E. and M. S. Sublette. 1965* Family Chivonomidae (Tendipedidae), p. 142-81. In A. Stone et al (eds.) A catalog of the Diptera of America North of Mexico. Agricultural Handbook No. 276, USDA, Wash. D.C. Syrjamaki, J. 1965. Laboratory Studies on the svarming behavior of Chironomus strenzkei Fittkau in litt. (Diptera, Chironomidae). Ann. Zool. Fennici 2:145-52. TBiol. Abstr., 1966:49753)* Thienemann, A. 1954. Chironomus. Leben, Verbreitung und virtschaftliche Bedeutung der Chironomiden. Die Binnengevasser, Band 20, 834 p. Thut, R. N. 1969. A study of the profundal bottom fauna of Lake Washington. Ecol. Monogr. 39:79-100* Townes, H. K. Jr. 1945. The Nearctic species of Tendipeaini ’/felptera, Tendipedidae (= Chironomidae^}/. Amer. Midland Natur.” 34:1-206. Usxngcx'j R. L. and. W. R. Ksllsn. 1955. The role of insects in sewage disposal beds. Hilgardia 23:263-321. Walshe, B. M. 1947a. On the function of hemoglobin In Chironoims after oxygen lack. J. Exp. Biol. Cambridge 2i-.329“ • 1947b. The function of hemoglobin in Tanytarsus_ (Chironomidae). J. Exp. Biol. Cambridge 245343-51* 1951. The function of hemoglobin in relation to filter ‘ feeding in leaf-mining chironomid larvae. J. Exp. Biol. 28:57-61. Weil, C. K. 1940. Summer hay fever of unknown origin in the south west. J. Allergy 11:361-75* Welch, P. S. 1948. Limnological Methods, McGraw-Hill Book Co. Inc. New York, p. 366. Wirth, W. W..and A. Stone. 1956. Aquatic Diptera, p. 372-482. In R. L. Usinger, je&J, Aquatic insects. Univ. Calif. Press, Berkeley and Los Angeles. VIII„ , APPENDIX A. Svnonomy of Glyptotendipes lohiferus (Say). G. lohiferus (Say), 1823* (1859b) (Chironomus). caliginosus Johannsen, 1905* (Chironomus; preocc. Meunier, 1904). ithacanensis Johannsen, 1908. (Chironomus; n. name for caliginosus Johannsen). americanus Kieffer, 1917* 149 150 B. Composition of Insecticides Tested: The following insecticides were selected to test their effects on egg, larval, and adult stages of the midge; 1. Malathion JE (emulsifiable concentrate) Agway Inc., Syracuse, N.Y. Active Ingredients: *Malathion.55$ Petroleum Distillate.30$ Inert Ingredients. 15$ *0,0, dimethyl dithiophosphate of diethyl mercaptosuccinate \j 2. Abate 4E (emulsifiable concentrate) American Cyanimid Co., Princeton, N.J. Active Ingredients; 0,0,0',0’-tetramethyl p,0'-thiodi-p-phenylene phosphorothioate.43$ Aromatic Petroleum Solvent.39$ Inert Ingredients.18$ 3. Naled (emulsifiable concentrate) Chevron Chemical Co., San Francisco, Calif. Active Ingredients; 1,2,-dibromo-2,2-dichloroethyl dimethyl phosphate . . . 25.4$ Xylene Base Solvent ...... 54.0$ Inert Ingredients.. ..20.6$ 4. Rabon (emulsifiable concentrate) Shell Chemical Co., Princeton, N.J. Active Ingredients: 2-chloro-l-(2,4,5-trichloropheyl) vinyl dimethyl phosphate . 24.3$ Petroleum Distillate . 60.9$ Inert Ingredients.14.8$ 151 C. Computation of Insecticide Dilutions: The following formula was used to compute dilutions of insecti¬ cides for use in laboratory studies: *X = C - 1 X = number of parts of diluent (water) S to add to one part of concentrate. C = per cent active ingredient of concen¬ trate . S = strength or per cent active ingredient in finished spray Calculations for the four insecticides tested: Contents of Yjo Stock Solution Malathion X = 55$ 1 = 55 - 1 = 54 1 part chemical 1 in 5^ parts water. Abate X = 4^ - 1 * 43 - 1 = 42 1 part chemical 1 in 42 parts water. Naled X = 25.4- 1 = 25.4 1 * 24.4 1 part chemical 1 in 24.4 parts water. Rabon X = 24.3- 1 = 24.3 - 1 = 23.3 1 part chemical 1 in 23.3 parts water. *from CDC Training Guide - Insect Control Series, Insecticides for the Control of Insects of Public Health importance, PHS Publica¬ tion #772, 1962 by Pratt, H. D. & Littig, K. S. p. II-33. 152 I ) DILUTION TABLE To prepare solutions of concentrations .indicated at left, take Concentration Desired number of milliliters of stock solution shown below, and make up to one liter with suitable dilution water. L 1,1 ppm PP*> Stock sol Stock sol: Stock sol Stock sol; Stock sol: Stock sol % or or 10% 1% . 1% . 01% . 001% .0001% mg/L pg/L 100 grn/L 10 gm/L 1 grri/L .1 gm/L . 01 gm/L . 001 grn/L loo. IToooTooU * 10. 100, 000 1000 5, 6 56,000 560 . * 3. 2 32, 000 320 1. 0 18,000 180 1 1.0 10,000 100 1000 . 56 5, 600 56 560 f . 32 3, 200 32 320 '. 18 1, 800 18 100 • . 1 § 10 100 1000 I 0 . 05G 560 5. 6 ,56 560 .032 320 3. 2 32 320 . 018 • 180 1. 8 18 180 . 01 100 1. 0 10 100 1000 . .0056 56 5. G • 56 560 . 0032 32 3. 2 32. 320 . 0018 18 1. 0 18 180 . 001 10 .-. 1. 0 10 100 1000 .0005G 5. 6 1 ' . , 5. 6 56 560 1 .00032 3. 2 ‘ / 3. 2 32 320 / .00018 1. 8 ’ /t 1. G 10 180 O O O » i 1. 0 1000 1.0 10 100 1000 .00005G . 56 560 • 5. 6 56 560 .000032 . 32 320 3. 2 32 320 .000018 . 18 180 , 1. 8 18 i. 180 .00001 .10 100 1. 0 10 100 1 .000005G . 056 ; 56 . 5. 6 56 . * .0000032 . 032 32 3. 2 32 .0000018 . 018 18 1. 8 18 __ .000001 . 010 10 1. 0 10 .00000056 . 0056 5. 6 5 6 .00000032 . 0032 3. 2 • ■ 3 0 . 00000018 I, , . 0018 1. 8 1 8 . 0000001 1 . 0010 1. 0 - 1. 0 »*. i. * - ! \ •. * r • i . -- -L- zr •j PHS' Training Guide - Bioas'say and Pollution Ecology*M 1963. Taft Sanit ary Engineering Center, Cincinnati, Ohio, p* II-10-6. 1 u> O mSZ •- c *- -r: O ' ^O ° w o - ~u 2 «> V'Z ° 5 ° to ».uy *1) > O' ^ <*) *rj »— ciaI — r« 153 *» ■ L. • 0 o *r JE *** "= t— • ■> u *3 U) o UJ O ,i— $ r- (D o > ^ •v- > „0 5 LO .-!v- ' ,,Yi-'I -J n- « 'u rr O- -2 Jr e ® ^ (J *w o < S*5<‘ S m _£ o _2 ^ ml-. <0 o 0) • • ^ :• w p cc U -PI cu P) Cl. rr1" w( o p •H •H W •Q t: p to P 0 o' •H c_> to o> u_ LU & o Ll. o;; cC_ co CO 1 ”T co; «M li O ■i'r , . o i Q p 1 3 o i -1 -p CL. c j ^ ** © ® tl g. Results of Statistical Analyses: 1. Laboratory insecticide studies. a. Eggs: Effects of 1 ppm4. J. Abate,/ malathion and Naled. ALOVA TABLE Sum of Mean Squares D F Square F Ratio Between Groups 14056.9228 2 7028.4614 23.5535** Within Groups 8056.9054 27 298.4039 Total 22113.8281 29 The F Ratio of 23.5535 is highly significant at F.01 level. Effects of 1, 10, and 1000 ppm Rabon. ANOVA TABLE Sum of Mean Squares D F Square F Ratio Between Groups 18586.1633 2 9293.0817 6.7769** Within Groups 37025.0462 27 1371.2980 Total 55611.2095 29 The F ratio of 6.77^9 is highly significant at F.01 level. 155 b . Larvae: Effects of 1 and 10 ppm Abate, malathion and Haled on first instar larvae. ANOVA TABLE 1 PPM Tests Sum of Mean Squares D F Square F Ratio Between Groups 2360.4155 2 1180.2077 11.2996** Within Groups 2506.7236 24 104.4468 Total 4867.1391 26 The F ratio of 11.2996 is highly significant at F.01 level. 10 PPM Tests Sum of Mean Squares D F Square F Ratio Between Groups 7176.8305 2 3588.4152 17.5594** Within Groups 4087.1757 20 204.3588 Total 11264.0062 22 The F ratio of 17*5594 is highly significant at F.01 level. Effects of single immersion treatment with 1000 ppm Abate, malathion and Haled on field-collected second and third instar larvae in tubes adhering to acetate samplers. ANOVA TABLE Sum of Mean Squares D F Square F Ratio Between Groups 8690.9738 2 4345.4869 4.2884* Within Groups 18239.5177 18 1013.3065 Total 26930.4915 20 The F Ratio of 4.2884 is significant at F.05 level. 156 c. Adults: \ Effects of malathion and Rabon at 0.1$ concentration on adults in aluminum screen cages, ANOVA TABLE Sum of Mean Squares D F Square F Ratio Between Groups 39398.4541 3 13132.8180 1.4741 Within Groups 320735.0541 36 8909.3071 Total 360133.5082 39 The F ratio of 1.4741 is not significant at F.05 level. 2. Field insecticide studies on adults. Effects of malathion and Rahon at concentrations of 1.4 Tbs actual and 1.0 Tbs actual per 100 gallons of finished spray, respectively. on the number of adults resting on mill -window screens. ANOVA TABLE Source ■ D F Sum of Squares Mean Squares F Treatments (T) 3 249639.447819 83213.149273 34.415** Dates (D) 6 629528.752899 104921.458817 43.393** Interaction (TXD) 17 242885.196667 14287.364510 5.909** Error 152 367527.328827 2417.942953 All three F ratios are highly significant at the F.01 level. 157 OVble 34. Measurement of some physical and chemical variables m canal water at the South Hadley Falls study area (Over- • flow) during 197°• H20 D.O. °jo Oxygen* pH Turbidity Saturation (in J.T.U.) Date Time Temp. °C ppm 3/7 noon 6 12 95 3/9 12:30PM 6 3/11 4:30PM 6 3/24 9:30AM 7 12 99 86 7.8 20 3/25 4:30PM 6 11 64 7.8 30 3/27 10:45AM 7 11 7.6 25 3/28 10:19AM 6 12 95 O 4/1 5:30PM 7 12 64 8.0 8 4 /4 10:30AM 6 14 58 7*8 45 4/7 4:30PM 7 11 64 8.4 15 4/10 1:30PM 9 11 80 8.4 32 4/11 3:00PM 8 11 71 7.3 16 4/13 4:30PM 9 13 85 8.3 4/20 4:30PM 8 12 74 4/25 1:00PM 9 12 83 7.8 7 4/29 12:45PM 11 12 109 7.9 11 5/2 12:30PM 13 11 ill 7.8 6 5/4 4:30PM 13 11 111 7.8 9 5/6 7:45PM 12 9 83 7.8 is 5/8 2:30PM 13 11 111 8.2 3 5/11 6:30PM 16 10 100 7.6 21 5/16 12:05PM 16 9 90 7.8 5 5/19 5:30PM 15 8 79 8.0 20 5/23 10:30PM 17 8 82 8.0 10 5/24 4:00PM 18 9 95 8.4 11 5/26 2:45PM 17 8 81 8.4 10 5/27 11:00AM 18 8 84 7.8 15 5/28 7:30PM l8 8 84 8.0 15 5/31 2:15PM 20 9 98 7.8 15 6/l 5 :00PM 22 9 100 7.8 10 6/8 8:15PM 22 9 100 8.0 10 6/12 9:30AM 23 7 80 8.6 8 6/22 9 :30AM 22 8 90 7.6 15 7/2 11:30AM 8 8.8 12 I/lp. 9:30AM 22 8 90 ns 18 *from Hawson*s nomogram, in Welch, P. S. 1948. Limnological Methods, McGraw-Hill Book Co. Inc., New York. p. 366 158 Table 35* Measurement of some physical and chemical variables in canal water at the Holyoke study area (Valley Paper Co. ice fender) during 1970* H20 D.O °Io Oxygen pH Turbidity Date Time Temp. °C . ppm Saturation (in J.T.U 4/7 4:30PM 11 4/28 3:00PM 8 5 A 4:30PM 12 11 100 7.6 19 5/19 5:30PM 14 9 86 8.0 15 5/21 1:00PM 14 9 86 5/23 10:45PM 15 9 88 8.4 11 5/26 3:00PM 16 8 80 8.3 3 5/27 11:30AM 16 8 80 8.0 10 5/28 8:00PM 17 8 81 7-8 5 5/31 2:45PM 17 9 93 7.8 1 6/1 4:30PM 20 10 109 7.8 5 6/3 4:00PM 21 9 100 8.0 1 6/4 2:15PM 21 8 89 7.8 1 6/8 9:00AM 20 8 86 7.4 4 6/12 8:15PM 23 8 94 8.0 2 6/22 9:00AM 21 9 100 7.6 10 7/2 11:00AM 10 -4- 9.2 • 20 H 2:00PM o 7/15 23 9 7.6 419 10:15PM 8/3 27 7 86 7.7 22 8/io 9:00PM 26 8 96 8.6 34 8/25 4:00PM 8 23 94 8.4 25 9/6 2:00PM 21 8 89 8.2 5 i O 0 vo O OOOOO(MCUO4-O(MC04-OC0O CO bO • • • • • • • •• 0 § P d rH HO O 0 0 4 iH VO bO P 0 Pi rd d P S •H Pi O s 0 O _P 0 p &H p p o o O O O O O H OOO 0000000-4* 0 i—1 o o O O OOOOOOOOCVJ P H Pi 0 0 LTN LTN LTN LfUTM/MAlA LTN O d 0 0 P 0 C P P P P 0 EH M -4* O • 0