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.

Class INSECTA
The Subclass Apterygota
    Characteristics: though lacking wings, very clearly much more like winged insects than
        previous groups -- ectognathous; only basal two antennal segments (scape, pedicel) with
        musculature; compound eyes and ocelli. Also, end of abdomen has long slender cerci and
        median filament (like mayfly nymphs). However, like entognaths, molt throughout life,
        have a few rudimentary abdominal appendages and indirect insemination.

    Order Archeognatha ("ancient mouth") -- Jumping Bristletails (or Microcoryphians);
            fossils found from Devonian period.  In GA, all in family Machilidae.
        One mandibular attachment, with mandibular lobes similar to crustaceans; humped thorax;
            many species can curl body and spring up ("jump") by smacking abdomen against
            ground; inhabit not only moist soil, but also dry woodlands/chaparral and even desert;
            will come to lights in GA.
        About 350 species are known; most in one family (the Machilidae).
    Order Thysanura -- Silverfish; in GA, all in family Lepismatidae.
        Mandibles like pterygotes; two attachments to head, chewing lobe arrangement different
            from machilids; compound eyes much reduced (but usually still present); fleet of foot;
            found in a variety of habitats, including animal burrows and in houses; omnivorous,
            eating a variety of detritus/organic matter.
        About 400 species are known; can be common in some houses in the 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