Review Sheet -- Test 1 (week 4) Biology 1224 B Entomology; James Adams

The SUBPHYLUM Hexapoda -- six-legged; includes the "Entognatha" and the Insecta

The "Entognatha", Apterygota, and Paleoptera -- Chapter 16, pages 327 - 334, and Chaps.
       18 - 21.  The lineages covered here represent the oldest living hexapodous groups, as
       well as the oldest occurring winged groups, the mayflies and dragonflies/damselflies.

Informal group ENTOGNATHA -- Chapter 18
    Characteristics of all 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).

    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.  Front legs held
            out in front, likely sensory in function (like antennae).  Observed feeding has been on fungi. 
            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.
    Order Collembola -- Springtails
        Tiny; with musculate antennae; unique "spring" mechanism (furca, tucked in retinaculum) in
            some on six-segmented abdomen (like early myriapod larvae); live in moist, typically soil,
            habitats, and are among the most important consumers in soil ecosystemes.  Some live on
            fungi, lower vegetation, the surface of water, and even on ice fields. May even travel by
            winds.  Reach adulthood by fifth/sixth instar but continue to molt.  Most bisexual.
        About 7000 species worldwide (even in coastal Antarctica); abundant in the U.S.
            Families in GA: Entomobryidae, Hypogasturidae, Sminthuridae, Isotomidae
    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.  Bisexual, and molt throughout life.
        About 800 species are known, particularly in the northern hemisphere; 60-70 species in U.S.

Class INSECTA
The Subclass Apterygota
-- Chapter 19
    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, which
        can be as long as four years.  Although they reproduce through indirect insemination, "mating"
        involves complex courtship, spinning of threads onto which spermatophores are placed and
        from which females may pick up the droplets of sperm.

    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.  Though indirect, mating courtships can be complex, and male may spin a line
            of silk upon which he places sperm droplets that the female is coaxed into picking up.
            They have abdominal styli, with nearby "vesicles" through which they imbibe water.
        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 370 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 (though variable), 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") -- Mayflies; Chapter 20
            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 distin-
                guished by muscular gills off of at least some of the first 7 abdominal segments, 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.  Naiads often
                easier to place to family than adults, because of more selection for different feeding styles.
            About 2500 worldwide, some 630 species in 16 families in the U.S. (see Table 20.1,
                page 371).    Common families in GA: 
                      Baetidae
- small, often with virtually no hindwings.
                      Ephemeridae - includes our largest species
                      Ephermerellidae, Leptophlebiidae, Heptageniidae, Oligoneuriidae, Caenidae,
                                Neoephemeridae, and Baetiscidae are the other families found in GA
        Order Odonata -- Dragonflies and Damselflies; Chapter 21
            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 third abdominal sternite -- in flight,
                male grasps female behind head with mating claspers, then female curls abdomen up un-
                derneath male to retrieve sperm ("flying in tandem"). Females dip abdomen in water to
                lay eggs, either freely or on vegetation.  Males often territorial and and guard spots with
                potential access to mates.  Males may remain in tandem until after egg laying or guard
                females to ensure sperm precedence.  Naiads also predaceous, with unique huge hinged,
                grasping labium; can catch fish, tadpoles, etc.  About 5000 species worldwide.
            Suborder Anisoptera -- Dragonflies
                Hold wings horizontally; hindwings broader at base than forewings; eyes allow nearly
                    360 degree vision. Males often defend territories.  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; some 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