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General Entomology EEB 286 Trichoptera and Lepidoptera Page 1 TRICHOPTERA and LEPIDOPTERA (AMPHIESMENOPTERA) Caddisflies, Moths, Skippers and Butterflies The superorder Amphiesmenoptera is one of the best supported sister-lineage relationships among the hexapod orders, with almost 20 unique traits (synapomorphies) that indicate a shared ancestry between Trichoptera and Lepidoptera. TRICHOPTERA NAME ORIGIN: Gk. trichos – hair; pteron – a wing. INTRODUCTION: Caddisflies. Larvae are important members of freshwater ecosystems (many fish eat them). Adults look similar to primitive moths. One of the largest lineages of aquatic insects, with over 7,000 species known worldwide and at least 1,600 species known from North America. An estimate places the total global fauna at over 50,000 species. The larvae are longer-lived than the adults. The adults are primarily reproductive agents. RECOGNITION: Larvae: • 2-40 mm in length • freshwater aquatics (a few terrestrial and marine forms) • 6-legged and lacking mid-abdominal prolegs with crochets of caterpillars • paired, hooked appendages at posterior end of the body • many construct elaborate cases which can often be useful when identifying specimens Adults: • mothlike, posture distinctive • long, simple antennae, often held forward • wing surfaces covered with hairs (rather than flat scales of Lepidoptera) • chewing mouthparts, palps well developed, mandibles reduced HABITATS: Larvae may be found in a diverse range of aquatic environments including springs, streams, lakes, rivers, bogs, marshes, and temporary pools. A few tolerate saline/marine environments. Cool running waters contain most trichopteran families, with less oxygenated environments supporting fewer taxa. Most larvae are leaf shredders dependent on leaf input from adjacent forests, others feed on a wide variety of food resources, including algae, organic debris, sponges, amphibian eggs and other arthropods. The crepuscular adults occur near their aquatic habitat (most fly at sunset, a few are diurnal) and are often attracted to lights. Adults feed principally on liquid food. COLLECTING: Adults can be collected at lights and by sweeping vegetation near aquatic habitats. They should be collected into and stored permanently in 70-80% EtOH. Dry collected and pinned adults are not uncommon in collections and are useful because they retain their colors better than alcohol preserved specimens. However, these are often more difficult to identify to species as a result of distortion due to drying. Larvae should be boiled in water and then permanently stored into 70-80% EtOH. If possible, collect and preserve the case with the larva. General Entomology EEB 286 Trichoptera and Lepidoptera Page 2 LEPIDOPTERA NAME ORIGIN: Gk. lepidos – scale; pteron – a wing. INTRODUCTION: Moths, Skippers and Butterflies. One of the four hyperdiverse, hexapod lineages with over 150,000 species known worldwide (in ca. 120 families). In North America there are ca. 900 species of butterflies and 15,000 species of moths (c.f. Hymenoptera-36,000 and Coleoptera-35,000), with an expected total of nearly 17,000 species including those currently undescribed. The Connecticut fauna is around 2300. It is estimated that the total world fauna will reach 250,000 species. The earliest fossil records of Lepidoptera date from the Jurassic. The success of the order was strongly influenced by the radiation of the Angiosperms during the Cretaceous. Lepidoptera have long been among favorite groups of collectors – there are more field guides for the identification of butterflies than any other insect group. Not surprisingly, butterflies have received the majority of the efforts devoted to the conservation of invertebrates. RECOGNITION: Larvae: • caterpillars (some barely distinguishable as such) • distinct head with up to 6 stemmata • labial spinneret (to spin silk) • often with prolegs on mid-abdominal segments (segs. 3-6) and on the last segment (seg. 10) • prolegs bearing small hooks termed crochets • larvae of leaf-mining taxa highly modified, many lacking legs, spinnerets, etc. Adults: • maxilla (galeae) often modified as proboscis • usually with 2 pairs of wings clothed in overlapping scales that easily dislodge • wingspans ranging from micromoths under 3 mm to saturniid moths reaching 26 cm HABITATS: Over 90% of lepidopteran species are phytophagous as larvae, very few are predaceous, and species of one superfamily are ectoparisites of Homoptera. Many are detritivores and fungivores. One of the few animal groups that can digest keratin (an animal protein in horns, finger nails, hair, and clothing) are moths. Adults feed on nectar, sap, decaying juices, urine, carrion, and dung (the latter few for sodium and other nutrients). Most leps are nocturnal, with the butterflies and skippers being the major diurnal groups. COLLECTING: Lep larvae must be dropped into almost boiling water for around a minute and then permanently stored in EtOH. Only freeze-dried specimens (that are stored frozen permanently) retain their colors with high fidelity, so another component to an ideal collection would include color photographs of living larvae. For killing leps use well charged cyanide or ethyl acetate killing jars with some soft tissue crumpled inside. Don’t use that same jar for other insects because they will end up being covered in scales. Large moths may be killed swiftly by injecting alcohol into the thorax with a hypodermic needle. Adult leps are fragile and require care in handling. Wings and antennae are easily broken off and the scales dislodge readily. If a freezer is accessible, it may also be used to kill leps. Glassine envelopes are useful to confine and transport leps; do not use the same envelopes for other insects (e.g. Odonates) because the envelope will be full of scales. Host plants are good places to find lep larvae, and adults can often be taken at flowers or at blacklights. Some species that are rarely found by any other means can be attracted to a fermenting sugar solution painted onto trees. For a quick-and-dirty faunal survey, leps can be stored permanently in envelopes, but for taxonomic purposes leps should be mounted on pins with their wings spread. A collection of fully spread leps takes more space and costs more to house than any other insect group. Small moths (wingspan <10mm) should be double-mounted with minutien pins. General Entomology EEB 286 University of Connecticut Fall 2006 Family: Pyralidae (pyralid moths) • • • • • • forewing usually narrow and triangular, often nearly triangular hindwing broad with enlarged anal area both maxillary and labial palpi usually project forward (adults often appear snouted) abdominal typanum facing thorax larvae internal feeders; some stored product pests third largest family of Lepidoptera; 1350+ spp. in NA Family: Geometridae (loopers, inchworms, geometers) • • • • • • • often slender-bodied and broad-winged, somewhat butterfly-like forewing pattern often continued onto hindwing abdominal tympanum that faces thorax subcosta bent abruptly at base in HW male antenna (bi-)pectinate or at least thickened; that of female simple larva missing first three (rarely just two) pairs of prolegs, looping in characteristic fashion second largest N.A. family with 1400 + spp. in NA Family: Saturniidae (giant silk and royal moths) • • • • • head and eyes relatively small; lacking functional mouthparts as adult medium to very large wings broad; frenulum absent or minute antennae plumose, considerably enlarged in male 68 NA spp. Family: Noctuidae (owlet, cutworm and noctuid moths) • • • • • • often stout bodied thoracic tympanum located beneath base of hindwing hindwing often with contrasting pattern, unmarked in many species subcosta + radius fused in hindwing for only a short distance beyond basal areole antenna simple, threadlike or rarely pectinate or plumose largest N.A. family with ca. 3000 spp. Family: Arctiidae (tiger moths) • • • • • 1 like noctuids1 but often brightly colored thoracic tympanum located beneath base of hindwing subcosta + radius fused in hindwing almost to middle of discal cell (usually) larvae are densely hairy, e.g., woolly bear ca. 260 NA spp. Phylogenetic studies suggest tiger moths are merely a derived lineage from within the Noctuidae