Review Sheet -- Test 1 (Week 5) Biology 1224 -- Entomology; James Adams
Infraclass Neoptera (90 % of all insects) -- wing flexing (over back) and folding; direct mating.
Division Exopterygota -- externally developing wings in immature instars and hemimetabolous.
Superorder Orthopteroidea --
Orthopteroid Orders (Chapter 16, page 331; Chapters 22 - 30)
Characteristics: typically have chewing mouthparts (not sucking); long antennae; long cerci;
numerous Malpighian tubules in the excretory system; large anal lobe on hindwing.
The relationships between the orders contained here are difficult to ascertain, though
certain orders have features that clearly link them (such as the roaches, termites and mantids; see
below, and Table 22.1). The rest of the orders included here, although sharing the characters
mentioned above, are not easy to place in an evolutionary tree. The placement of the Zoraptera is
uncertain to the point where it is not even clear whether they are orthopteroid or hemipteroid.
Order Blattodea (including former Isoptera) --
the roaches and termites (Chapter 22)
Roaches -- Broad, flattened body; hypognathous head with large compound eyes; prothorax
with shield-like notum. Wings with numerous longitudinal (and parallel) veins, with smaller cross-
veins; forewings somewhat sclerotized (protective tegmen); hindwings membranous with longitu-
dinal pleats (for folding), which allows for expanded area for flight. Legs typically spiny, with 5
tarsal segments. Scent glands on top and/or bottom of some middle abdominal segments; male
genitalia strongly asymmetrical. Courtship typically involves male pheromones and stridulation.
Females lay multiple groups of eggs in two rows in a semi-protective ootheca, often carried by
the female for some time. This egg arrangement is seen in mantids (with ootheca) and primitive
termites (without ootheca). Eggs often slow to hatch, sometimes taking over a year. However,
some females actually exhibit live birth. Adults also relatively long lived, with some species living
four years or more.
Not known to pass diseases, but often associated with unkempt circumstances. Indirect
wing muscles quite reduced, with the direct muscles normally involved in pitch control apparently
involved in downstroke (same in mantids and termites). Life styles quite varied, including some
semi-social, wood feeding species with internal, wood-digesting protozoan symbiotes (similar
to termites). A few species parthenogenetic. First instar non-feeding, molts quickly.
About 4000 known species, 50 in the U.S., with some 30 species commonly inhabiting
human buildings in some part of the world.
Families likely to be encountered in GA:
Blattellidae: Includes most outdoor ("wood") roaches and the German Cockroach.
Blattidae: Includes the large pest species American and Oriental Cockroaches.
Termites -- Social, with only the reproductives being winged, and then only for a short dis-
persal flight. Frons with frontal pore in most, extremely enlarged into a "squirt gun" in some
species that have nasute soldiers. Thorax with weakly sclerotized tergites and membranous ster-
nites. Legs short; cerci typically short. Wing musculature as in mantids and roaches.
Life style specialized to feed on cellulose (including dead wood), the most abundant
terrestrial organic compound; may include crop plants and seeds, dried foods, paper, hides, etc.
Important decomposers, so not really "bad". Like the few wood-feeding roaches, have cellulose
digesting intestinal protozoan symbiotes. Reproductive females become large, and in some
species huge, non-mobile egg-laying machines. Females control caste of individuals with
reproduction suppressing pheromones. Castes may include nasute and mandibulate soldiers
(with large, sharp mandibles) -- soldiers most important in defending against ants -- and workers.
The more primitive termites seek out chambers that may never contain more than a few thousand
individuals; more advanced species build tunnel galleries, containing millions of individuals.
Workers and soldiers may live for four years, reproductives for fifteen. The galleries may be
inhabited by successive generations for half a century. The nests may control humidity and
temperature, enough so that a few species farm fungi.
Termites are a principle food for a number of vertebrate predators -- anteaters, armadillos,
aardvarks, pangolins, meercats, marsupial anteaters and spiny echidnas.
Other insects, particularly staphylinid (rove) beetles, share space in termite colonies --
these are called termitophiles. Some species consume eggs or brood, others simply scavenge
what they can.
About 2300 species known, but few species from U.S.
Families in GA include: Termitidae, Kalotermitidae, Rhinotermitidae
Order Mantodea --
the mantids (Chapter 23); one family only (Mantidae) in North America
Head typically small (but with large eyes); incredibly mobile on narrow, sclerotized
prothorax (neck); antennae narrow; raptorial front legs; wings similar to cockroaches -- forewings
toughened, hindwings pleated and much broader for flight; females often have somewhat more
reduced wings (poor flyers); tarsi 5-segmented. Short cerci; male with asymmetrical genitalia.
Wings and wing-musculature similar to roaches, as are the male genitalia; ootheca protects
eggs. Adults predatory, some large species occasionally feeding on vertebrates. Males must be
careful during courtship, females occasionally consume male after or even during copulation. First
instar nymph is non-feeding (also like roaches), and quickly molts.
About 2000 species worldwide, with most species in the tropics.
Order Grylloblattodea --
the rockcrawlers or rockhoppers (Chapter 24)
Somewhat elongate in body, looking a bit like a cross between a roach and a cricket;
reasonably long antennae (similar in length to thorax); reduced (sometimes absent) eyes and no
ocelli; prognathous mouthparts; no wings; long legs (for walking, of course) with 5 tarsi; long
cerci; straight, short ovipositor in female. Nymphs quite similar to adults (no wings).
Mostly found at higher elevations, in cool, moist habitats, often near snow fields. Activity
is almost always at low temperatures; omnivorous, eating plants and small animals (other insects);
eggs laid in protected moist locations, with long period (up to a year) before egg ecloses. Add
antennal and cercal segments with each molt; adult instar typically at eight years!
16+ known species in one family (Gryllobattidae), found only in northern and western
areas of North America and eastern Asia, usually at high elevation. No species in GA (sigh . . .).
Order Mantophasmatodea -- the heelwalkers or
gladiators (Chapter 25)
Elongate body (like phasmids -- stick insects), predaceous on other insects (like mantids),
hence the name of the order. Molecular data suggests relationships with grylloblatids or phasmids.
Found only in southern Africa, living members of this order were only recently discovered
(2001). Only a few species known.
Order Dermaptera ("skin winged") --
the earwigs (Chapter 26)
Small to medium size, and typically elongate and somewhat flattened; prognathous; eyes
can be normal in size or absent in some species; long antennae; prothorax typically large and
flexibly articulated with mesothorax; small mesothorax with typically small elytriform (sclerotized)
wings, which are held together at rest by bristles on the median mesonotum; metathorax with
large membranous wings with radiating venation; hindwings can folded up like an accordion, and
tucked up under the small elytra when not in use; some species without wings, or dimorphic
(males with wings, females without). Legs adapted for walking with 3 tarsal segments; abdomen
with 8 segments in female, 10 in male. Cerci heavily sclerotized and pincher like. In the more
primitive families of earwigs, the males have paired parts (two aedeagi), the only group other than
mayflies to exhibit this feature.
Adults look a bit like the dipluran family Japygidae, species of which have pincher-like
cerci (but never wings), and also Rove Beetles (Coleoptera, family Staphylinidae) which have
similar wing arrangement but no pincher like cerci. The pincher-like cerci can be used for
defense, courtship, and even prey capture. Known species are omnivorous or predatory. Some
species are parasitic or commensal (living with another animal but only to the benefit of the
earwigs) with vertebrates and these species never have pincher-like cerci. The parasitic species
typically also lack wings, have reduced eyes, very flattened body, and internal embryonic
development (which means they give birth to live young).
Dermapterans are retiring species, finding crevices to hide in during the day, aided by the
smooth cuticle, flattened body, and tucked-away wings. Females lay eggs in shelters; protects
both the eggs and first-instar nymphs; nymphs must leave soon after or mom gets cannabalistic.
About 1800 species worldwide, with most species in the tropics.
Families in GA: Forficulidae, Carcinophoridae, Labiidae, Labiduridae (1 species)
Order Plecoptera --
the stoneflies (Chapter 27)
Body typically softly sclerotized and flattened; head with long antennae; often
prognathous (though sometimes hypognathous); mouthparts similar to Orthoptera, chewing and
rather nondescript, with distinctive palps on both maxillae and labium; large laterally protruding
eyes; long membranous wings with longitudinal veins and frequently lots of crossveins; wings
extend past the end of the abdomen when folded; forewings narrower than hindwings; hindwings
pleated for folding; some species (especially semi-aquatic species or cold weather species) are
wingless; legs well developed with 3 tarsal segments. Thorax and/or abdomen sometimes with
remnants of nymphal gills; thoracic pleura have no distinctive sutures (no episternite and
Naiads are similar in body structure to the adults, but with longer cerci, and (of course) no
wings. Respiration in the naiads of some species is through the body surface; other species have
gills in various places (head, thorax, legs, abdomen, even inside rectum in different species).
Naiads in last instar crawl out of the water for imaginal molt. Most frequently encountered in
cool streams; need well oxygenated water, and are therefore good pollution indicators (often
disappear quickly in polluted streams).
Adults typically stay near cool streams. Even though the wings are large, they typically
are weak fliers and often run instead. Activity periods vary between species (some diurnal,
others nocturnal and will come to lights). Herbivorous as adults (though some nymphs are pre-
daceous on mayfly nymphs), feeding on algae, lichens, foliage, pollen (though some don't feed).
Some species are active during the coldest months, a useful ability to have to reduce predation.
Mating may involve courtship with male "drumming"; may mate multiple times. Females
may lay several hundred to several thousand eggs, typically carried briefly on venter of curled
abdomen, then dropped into the water. Emergence within a few months, though some can
survive in dried streambeds for an extended period. Lifespan after hatching is one to four years.
About 3700 species worldwide, with a significant (700 species) fauna in U.S. and Canada.
Common families (though encountered only near pristine bodies of water) include: Perlidae,
Perlodidae, Pteronarcyidae (biggest species), Chloroperlidae, Peltoperlidae, Nemouridae,
and Leuctridae, though few species fly during the fall (sorry!).
Order Embiidina or Embioptera --
webspinners (Chapter 28); in three families
Social; superficially similar to stoneflies and/or earwigs; cynlindrical body for living in
tubular web structures; prognathous; relatively small eyes and no ocelli; males typically with
wings (with simple venation), females with narrower thorax and without wings in females; legs
short with 3 tarsal segments; forelegs with enlarged basal tarsal segment, which contains glands
for silk production; short, two-segmented cerci. Nymphs similar to adults.
Since only males winged, dispersal is limited, and males do not feed after dispersal to new
colonies. After mating, males may be consumed by females. Eggs are laid within galleries, and
newly emerged nymphs are tended by mothers. Life is spent in self-constructed silken galleries,
which are expanded as individuals grow. Adults and various nymphal stages occur together in
same galleries, which are centered around protective retreats. Galleries are narrow, so individuals
quite able to walk backwards, including males that fold wings tightly over the back. Food includes
plant materials to which tubes are built. Habitats vary from the humid tropics, to arid habitats
(where galleries more subterranean and males wingless), to moist habitats.
360+ species described, though because of secretive habits, many more (1000+?)
probably remain to be discovered. In U.S., only 8 native and 3 introduced species.
Difficult to find, but at least the family, Oligotomidae, is found in GA.
Order Orthoptera -- Grasshoppers, Crickets, Katydids, etc. (Chapter 29)
Elongate, somewhat cylindrical (or flattened vertically) body; hindlegs in virtually all
species modified for jumping. Head hypognathous, with LARGE, STRONG mandibles in many
species; well developed eyes and reasonably, sometimes exceptionally, long antennae. Shield-like
(sclerotized) pronotum; forewings narrow, toughened (tegmen); hindwings large, membranous,
with long veins (and numerous crossveins); hindwings pleated for folding (like roaches, mantids,
earwigs, stoneflies -- in other words, like the other orthopteroid orders). Tarsi with 1 to 4 segments;
hind femora are particularly enlarged and muscular; tibiae, particularly the hind tibiae and tarsi with
numerous sharp spurs; when detained, orthopterans kick with the spurred hindlegs; can shed
hindlegs to escape. Cerci short (one segmented). Nymphs similar to adults, except reduced
genitalia and wings, though in some species the coloration may change dramatically from early to
later instars. A few species are subterranean and lack wings. Hearing is typically well developed,
and most species'males produce sound during courtship.
20,000 species worldwide; includes some important herbivorous pests of crop plants.
Caelifera -- typically diurnal; with excellent vision and hearing; jump (and fly) to escape
predators. Antennae relatively short. Typically live on the ground (not up in the trees), and
therefore particularly abundant in open habitats. Most are herbivorous. May have brightly
colored hindwings to attract mates and even advertise distastefulness to predators. Many of these
species will "spit" (regurgitate) as a predatory defense mechanism. Auditory (hearing) organs on
the first abdominal segment. Stridulation is accomplished with hindlegs rubbing against folded
forewings. Grasshoppers in flight often produce an audible "buzz." Females typically lay eggs in
clutches in the soil, and surrounded by an ootheca. Likely encountered families included in this
*Acrididae: the grasshoppers and locusts
Tetrigidae: the pigmy grasshoppers
12,500 species worldwide.
Ensifera -- typically nocturnal. Cryptically colored to avoid predators. Antennae are
often extremely long for sensing movement nearby. Movement slow unless encounter another
organism. Typically omnivorous (opportunistic) or even predatory (don't let a big katydid bite
you!). Auditory organs are located on the front tibiae, and wings are rubbed together to produce
sound. Some species, particularly katydids, may synchronize sound production which results in
the song being very loud. Females typically have long ovipositors, and lay eggs singly by inserting
them in plant stems or the soil. Likely encountered families included in this suborder include:
*Tettigoniidae: the katydids
*Gryllidae: the crickets (and snowy or tree crickets)
*Gryllotalpidae: the mole crickets
Raphidophoridae: the cave and camel crickets (wingless)
Some references include Oecanthidae (the snowy & tree crickets) as a separate family
7,500 species worldwide.
You need to KNOW the families marked with a "*."
Order Phasmatodea --
the walkingsticks or stick insects; leaf insects (Chapter 30)
Insects of medium to large size (length), very elongate to flattened and leaf like in some
tropical species. Head typically with long, thin antennae; prognathous. Prothorax typically short,
meso- and metathorax longer, especially in winged species; thoracic segments flexibly articulated.
Wings, for species that have them, like other orthopteroid insects. Legs very long; 5 tarsal
segments. Cerci short, with one segment. Asymmetrical genitalia in the males (like roaches, but
not orthoptera). Nymphs very similar to adults.
Species may have wings, body, even legs expanded to look like various plant parts
(thorns, leaves), but species in GA are typical stick insects. Often move slowly with back and
forth movement (supposedly simulates waving in the wind). At rest, often hold forelegs straight
out in front. May drop (like a stick) when disturbed; legs freely dehisce (come off) when
grasped. Legs may be partially regenerated during nymphal molts.
These insects are all herbivorous. Males typically quite smaller than females. Eggs laid
singly on vegetation or dropped to the ground; occasionally in soil. Eggs, particularly those glued
to plants, are toughened and may resemble seeds.
About 3000+ species known; all species in North America are Stick Insects (no Leaf
Insects) in the family Phasmatidae.
As stated above, the placement of the Zoraptera is tentative in the
Orthopteroidea, as they
share some characteristics with the hemipteroids. Nymphs found in same habitats and utilize
similar foods as the adults.
Order Zoraptera --
the zorapterans (Chapter 31)
Very small; prognathous with mandibulate mouthparts; prothorax typically large, often
larger than meso- or metathorax; several species wingless; wings membranous with reduced
venation in alate species; forewings larger than hindwings (typical of hemipteroids); legs adapted
for walking, with two segmented tarsi; tiny cerci. Asymmetrical male genitalia, in some ways like
the roaches and termites, wing musculature also similar to roaches; however, nervous system is
concentrated in the thorax and anterior abdomen, the larger forewings have reduced
venation, more like hemipteroids. Resemble termites a bit and often inhabit dead wood,
moist leaf litter, etc. apparently feeding on fungi and occasional small arthropods. Some species
have different adult forms, wingless and alate, with the alate forms probably for dispersal;
development of the winged forms may be in response to unfavorable environmental conditions. In
at least one species, males do a courtship dance; while mating, female drags male around on back.
About 30 known species, all in the family Zorotypidae. One species (Zorotypus hubbardi)
occurs here in the SE U.S.