Review Sheet (#2) -- Test 2 Biology 1224 -- Entomology; James Adams
Infraclass Neoptera -- Division Endopterygota --
around 85% of all insects are endopterygotes;
which are virtually all holometabolous. Advantage of holometabolous development? Separation
of utilization of resources between life stages. Some have larvae that are similar in body plan to
adults (Megaloptera). At the other end of the spectrum, some (dipterans, hymenopterans) have
larvae with no eyes, no legs, antennae extremely reduced, and nubby mouthparts. Includes three
superorders: Neuropteroidea, Mecopteroidea, and Hymenopteroidea.
Superorder Neuropteroidea --
Neuropteroid Orders (Chapter 16, page 333; Chapters 36-40)
Orders in this superorder are linked by similarities in larval stages of some of the included
families, though larvae of some of the included families are quite bizarre, modified for their particular
life style. The first three orders have membranous forewings and hindwings with lots of crossveins
(Neuroptera -- "net wings"), the last two use their membranous hindwings for flight.
Order Megaloptera --
Dobsonflies, Fishflies, Alderflies
Large to very large insects; prognathous; strong chewing mouthparts; large eyes; thorax
large, with segments flexibly articulated; large, membranous wings with forewings slightly longer.
Larvae aquatic (called hellgrammites), and also with strong prognathous mouthparts for their
predaceous life style; lateral extensions on abdominal segments 1 - 7 (8), some with gill tufts;
terminal segment with median filament (Sialidae), or paired prolegs (Corydalidae). Pupae are
dectitious, mobile; though non-feeding, mandibles still can be used for defense; pupation occurs in
an earthen cell.
Similar as adults to Neuroptera, though Megalopterans have an anal lobe in the hindwings
that neuropterans do not. Larvae quite different, however (neuropterans have some parts adapted
for sucking), and more similar to some aquatic beetle larvae.
Adults apparently do not feed; mandibles for defense and mating displays. Once mated,
females may lay eggs continuously for weeks, laying several thousand eggs on vegetation, etc.
overhanging the water. Larvae drop into the water after hatching, take one to several years to
300+ species worldwide; found around cool, well aerated streams (similar to Plecoptera).
Two families: Corydalidae -- Dobsonflies and Fishflies (common in GA; wings large and
held flat over back); Sialidae -- Alderflies (uncommon in GA; smaller with wings rooflike)
Order Raphidioptera --
Snakeflies; most species in U.S. in family Rhaphidiidae
Medium sized; prognathous with strong mouthparts; prominent eyes; prothorax long and
slender ("neck-like"); wings very much like Neuroptera; female with long ovipositor. Larvae
terrestrial; similar to adults (with no wings); abdominal segments with numerous bristles for added
grip. Pupae dectitious and mobile; pupation in an loose, earthen cell. Life cycle of two years.
Both larvae and adults are voracious predators; elongate, flexibly articulated prothorax
allows insects to "strike" like a snake. After mating, female lays eggs (up to 800) in small groups
in crevices in bark; larvae live under bark, rotten wood, leaf litter, etc.
Around 175 species worldwide; inhabit woodland habitats, but all in western U.S. (Sigh)
Order Neuroptera ("net"
Lacewings, Antlions, Owlflies
Small to quite large; adults with chewing mouthparts; large lateral eyes; prothorax quite
mobile (like in the Snakeflies); large wings membranous with numerous crossveins; slightly larger
forewings, with wings held rooflike over body; wing coupling mechanisms present in the stronger
fliers; abdomen long, cylindrical without cerci, last two segments with adhesive pads for gripping/
movement. Larvae with long, pinching mandibles/maxillae, modified for sucking. Pupae exarate/
dectitious; formed in a silken cocoon, produced from secretions of the Malpighian tubules; the
motile mouthparts are used to emerge from the cocoon, which typically happens before eclosion.
Adults largely predaceous, intriguing when consider the relatively soft body and not
particularly strong flight. However, most species have scent glands that release nasty smelling
compounds for predatory protection. Larvae also predatory, sucking juices out of prey, which are
largely absorbed (though not completely), necessary since larval gut ends blindly in the midgut. The
gut is completed in the pupal stage, and fecal material is voided shortly after eclosion.
Eggs deposited on a variety of surfaces. Some species stick eggs up on long stalks
(chrysopids, mantispids and berothids). Larval form is variable B long, relatively slender with long
legs and prehensile abdomen in the roving (lacewing) predatory types; globular or flattened with
huge jaws in sit and wait types (antlions, often in constructed pits; owlflies, on vegetation). A few
larvae are aquatic, such as Sisyridae (Spongillaflies) -- the larvae are similar to lacewings, but feed
exclusively on freshwater sponges. Larvae in several families may have extra bristles that not only
help anchor larvae but allow larvae to stick litter and husks of prey bodies to their own body for
camouflage. Mantispid larvae are free moving in the first instar, but find appropriate hosts (spider
egg masses, hymenopteran brood) and become parasitic and grublike in later instars. Berothid
larvae also motile in first instar, invading ant nests, eating ant larvae and subduing mature ants
with chemicals as they bloat themselves. Larvae that live on abundant prey complete development
quickly; those that feed on sporadic prey may take several years to complete development.
5000+ species, with 2000 a piece in the Chrysopidae and Myrmeleontidae; some families
considered uncommon (mantispids, berothids) can be frequently encountered in Georgia.
Likely encountered families in the Neuroptera include:
Coniopterygidae: Dusty-wings; minute, whitish powder covers body and wings.
*Berothidae: Beaded Lacewings; apex of forewing pronounced.
*Chrysopidae: Green Lacewings
*Hemerobiidae: Brown or Golden Lacewings
*Mantispidae: Mantidflies; some mimic wasps in tropical areas
Order Strepsiptera --
Twisted-Winged Parasites (Chapter 40); most similar to some beetles
Very small, with significant sexual dimorphism. Males with large, transversely protruding
head/eyes; pro-/mesothorax small; forewings small, narrow, elytriform; hindwings large and
membranous with few veins. Females are wingless and grublike. First instar larvae quite motile,
but later instars grublike for life on host. Pupa exarate; formed in cuticle of last instar larva.
These are parasites on Thysanura, Blattodea, Mantodea, Orthoptera, Hemiptera*, Diptera,
and Hymenoptera* ("*" most common); adults don=t kill hosts, and most females never leave
host body. Females release pheromones which attract male to host for mating; females produce
eggs (up to 75,000), which remain inside until hatching. Upon hatching crawl/hop until encounter
immature of appropriate host; burrows into host using cuticle softening mouth secretions. For
those species that parasitize hymenopterans, first instar larvae are deposited on flowers. The
larvae either hop onto host adults which carry them back to the nest, or are ingested with nectar
and regurgitated to the brood. Parasitized individuals are usually developmentally stunted.
Around 550 species are known, though there are probably a large number yet to be
described, with the family Stylopidae (which parasitizes Hymenoptera) being the most diverse.