Review Sheet -- Test 1 (week 4) Biology 1224 B Entomology; James Adams
The SUPERCLASS Hexapoda -- six-legged; includes three classes as indicated below
The Parainsecta, Entognatha, Apterygota, and Paleoptera --
Chapter 15, pages 304 - 314;
and Chapters 17 - 21. The lineages covered here represent the oldest living hexapodous
groups, as well as the oldest occurring winged groups, the mayflies and dragonflies/damselflies.
The CLASS Parainsecta -- considered by some to include
the orders Protura and Collembola
The CLASS Entognatha -- considered to include only the Diplura
More recent studies suggest the following relationships:
The CLASS Collembola
The CLASS Nonoculata (no eyes) -- which includes the Protura and Diplura
Even more recent studies suggest that each former order be given it's own
separate class, which is
what you see below.
Characteristics of all three of the following classes/orders: all antennal segments are musculate
(if present); entognathous; mandibles with a single attachment point to the head; rudimentary
abdominal appendages, especially on front segments; spermatophore (sack containing
sperm) deposited on ground and then picked up by female (indirect insemination).
Class/Order Collembola -- Springtails
Tiny; with musculate antennae; unique "spring" mechanism (furca) in some on six-
segmented abdomen (like early myriapod larvae); live in moist, typically soil, habitats,
but some live on the surface of water, and even on ice fields. May even travel by winds.
Reach adulthood by fifth/sixth instar but continue to molt.
About 7000 species worldwide (even in coastal Antarctica); abundant in the U.S.
Families in GA: Entomobryidae, Hypogasturidae, Sminthuridae, Isotomidae
Class/Order Protura -- Proturans (3 families in N. America; none common)
Tiny; no antennae or eyes on cone-shaped head; anamorphic (add segments with molts) --
9 segments at hatching, 12 in adult (which continues molting); soil dwelling. Two main
families in Georgia -- Eosentomidae (with a tracheal system) and Acerentomidae (without
a tracheal system).
About 500 species worldwide; found in most regions of the U.S, 20 species total from U.S.
Class/Order Diplura -- Diplurans (2 families possible in GA: Campodeidae and Japygidae)
Antennal segments musculate (like springtails); entognathous; no eyes; mandibles with
distinct chewing (incisor) lobe; maxillae like in insects; labial palps; 10 or 11
abdominal segments, with rudimentary appendages on several; cerci on end of
abdomen (like insects); inhabit moist, cool habitats in soil/moss. Generalist feeders, on soil
inverts, living and dead plant and fungal matter
About 800 species are known, particularly in the northern hemisphere; 60-70 species in U.S.
Subclass Pterygota --
the winged insects
Characteristics: most are winged; two attachments for mandibles to head; (10-)11 segments
on abdomen, only the last with appendages (cerci); molt only until reaching sexual
maturity and then exhibit direct insemination in most (mating).
Infraclass Paleoptera ("old wings")
Characteristics: No wing folding (can't pull wings in); short, setaceous antennae; wings
with lots of veins and crossveins; 10 abdominal segments; have aquatic naiads with gills.
Order Ephemeroptera ("Ephemeral wings"; "ephemeral" means short-lived) -- Mayflies
Long slender body; non-functional mouthparts in adult (therefore short life); large
forewings, but hindwings small (occasionally absent); wings held vertically at rest;
flight mechanism is indirect; long cerci and usually median filament on abdomen;
paired penes and oviducts; unique winged subimago stage, which flies and then
molts into imago. Naiads distinguished by gills and the indicated three extensions off
of abdomen; naiads vary in diet (a few are predaceous). Because of short life, often
synchronously emerge in large groups. Mating in flight; female lays lots of tiny eggs;
in some species, females enter water to lay eggs.
About 2500 worldwide, some 630 species in 16 families in the U.S. (see Table 20.1,
pages 349-350). Common families in GA:
Baetidae - small, often with virtually no hindwings.
Ephemeridae - includes our largest species
Ephermerellidae, Leptophlebiidae, Heptageniidae, Oligoneuriidae, Caenidae,
and Baetiscidae are the other families found in GA
Order Odonata -- Dragonflies and Damselflies; about 5000 species worldwide.
Huge eyes on large, mobile head (for predaceous lifestyle -- catch other insects on the
wing); head narrowed at attachment with thorax ("neck"); only flying insects with
direct flight mechanism, with huge flight muscles; only insects to move fore- and
hindwings out of phase (makes "hovering" possible); sacrifice walking muscles (can
only grasp with legs, not walk); legs successively longer toward rear, creates basket
for catching prey; long, thin abdomen. Male deposits sperm in secondary copulatory
organ on second (or third) abdominal sternite -- in flight, male grasps female behind
head with mating claspers, then female curls abdomen up underneath male to retrieve
sperm ("flying in tandem"). Females dip abdomen in water to lay eggs. Naiads also
predaceous, with unique huge hinged, grasping labium; can catch fish, tadpoles, etc.
Suborder Anisoptera -- Dragonflies
Hold wings horizontally; hindwings broader at base than forewings; eyes allow nearly
360 degree vision. Naiads have internalized rectal gills
In U.S., @300 species in several families; common families in GA include:
Aeshnidae, Gomphidae, Corduliidae, Libellulidae, Cordulegastridae
Suborder Zygoptera -- Damselflies
Hold wings up over back (thorax tilted toward rear); fore- and hindwings similar in
shape; males have extra "scoop" to remove previous males sperm. Naiads have
3 pairs of externalized gills near end of abdomen; some tropical species may live
in isolated water puddles and venture out at night to hunt.
In U.S., @130 species in three families: Caenagrionidae, Calopterygidae, Lestidae