Entomology List/Ametabolous and Apterygota

This page contains information on Ametabolous and Apterygote Orders. For information on how to use this list, please see the first section on the Entomology List page. For more general information about the event, see Entomology.

Protura (telsontails, proturans)
Entognathous, sucking mouthparts all enclosed within head capsule, consist of thin mandibles & maxillae, use mouthparts to scrape off food partibles, which they draw into mouth & mix with saliva; No antennae; No eyes; Head Conical, Pseudoculi (eye shaped organs for smell) present (may be remnants of vestigal antennae); Wingless; FL used as sensory function, 5 segmented, each leg tipped with a single claw; 12 Abdominal Segments (newly hatched have 9, each time they molt, one is added), Small ventral styli located on abdominal segments 1-3, Cerci & Abdominal filaments entirely absent; Genitalia are internal & the genital opening lies between the eleventh segment & the telson of the adult; Some lack a tracheal system (All gas exchange occurs through the integument); .6-1.5mm; Unpigmented, most white or ivory; Postanal Telson @ end of cylindrical body; None pests, help break down/recycle organic nutrients; Always moist, usu in the humus & leaf mold of temperate deciduous forests, some live 10” underground; Uncommon; Herbivores; Organic matter released by decay & mycorrhizal fungi, dead Acari, & mushroom powder in culture; Most primitive hexapods, smallest arthropod class; “proto” – first (original) “ura” – tail; Discovered by Antonio Sylvestri in 1907 near Syracuse, New York;
 * Head: Entognathous (retracted within the head), sucking mouthparts, consist of thin mandibles & maxillae, use mouthparts to scrape off food particles, which they draw into mouth & mix with saliva; No antennae; No eyes; Head Conical, Pseudoculi (eye shaped organs for smell) present (may be remnants of vestigial antennae);
 * Thorax: Wingless; FL used for sensory function, 5 segmented, each leg tipped with a single claw;
 * Abdomen: 12 Abdominal Segments (newly hatched have 9, each time they molt, one is added), Small ventral styli located on abdominal segments 1-3, Cerci & Abdominal filaments entirely absent; Some lack a tracheal system (All gas exchange occurs through the integument);
 * Sexual Dimorphism: Genitalia are internal & the genital opening lies between the eleventh segment & the telson of the adult;
 * Misc Anatomy: .6-1.5mm; Unpigmented, most white or ivory; Postanal Telson @ end of cylindrical body;
 * Human Impact: None are pests, help break down/recycle organic nutrients;
 * Habitat: Always moist, usu in the humus & leaf mold of temperate deciduous forests, some live 10” underground; Uncommon;
 * Diet: Organic matter released by decay & mycorrhizal fungi, dead Acari, & mushroom powder in culture; Herbivores
 * Explanation of Name: roto” – first (original) “ura” – tail;, refers to the lack of advanced or specialized structures at the back of the abdomen
 * Misc: Most primitive hexapods, smallest arthropod class; Discovered by Antonio Sylvestri in 1907 near Syracuse, New York;

Collembola (springtails, snow fleas)
Piercing-sucking, entognathic mouthparts; Antennae short with 4-6 segments: Compound eyes absent or reduced to a cluster of not more than 8 ommatidia; Wingless; Most have short legs; Unique, tube-like structure, the collophore is located ventrally on the first abdominal segment (possibly helps maintain water balance by absorbing fluid), Forked jumping organ (furcular) on 4th abdominal segment; The furcula is retracted against the ventral wall of the abdomen & held there, in cocked position, by a special catch (the tenaculum) on the third abdominal segment. Effective adaptation for avoiding predation; Genital opening on 5th abdominal segment; Young similar in appearance to adults but paler, some parthenogenetic, most sexual; 1-5mm; Variety of colors; Variable body shapes; Body frequently clothed with scales; Decompose/ recycle organic materials, some are plant pests; Common in grassy/wooded areas decaying organic matter, spores, some inhabit the intertidal zone; Common, worldwide; Scavengers, use ants or termites as a host (commenalism); Feed on decaying vegetation & soil fungi; Most abundant soil-dwelling arthropods; “coll” – glue, “embol”- wedge (referring to furcula); Appear to have evolved in cold climate;
 * Head: Piercing-sucking, entognathic mouthparts; Antennae short with 4-6 segments: Compound eyes absent or reduced to a cluster of not more than 8 ommatidia;
 * Thorax: Wingless; Most have short legs, 1 segmented tarsi;
 * Abdomen: Unique, tube-like structure, the collophore is located ventrally on the first abdominal segment (possibly helps maintain water balance by absorbing fluid), Forked jumping organ (furcular) on 4th abdominal segment; The furcula is retracted against the ventral wall of the abdomen & held there, in cocked position, by a special catch (the tenaculum) on the third abdominal segment. Effective adaptation for avoiding predation;
 * Sexual Dimorphism: Genital opening on 5th abdominal segment;
 * Life Cycle: Young similar in appearance to adults but paler, some parthenogenetic, most sexual reproduction;
 * Human Impact: Decompose/ recycle organic materials, some are plant pests;
 * Habitat: Common in grassy/wooded areas decaying organic matter, spores, some inhabit the intertidal zone; Common, worldwide;
 * Diet: Scavengers, use ants or termites as a host (commenalism); Feed on decaying vegetation & soil fungi;
 * Explanation of Name: “coll” – glue, “embol”- wedge (referring to furcula that was once thought to function as an adhesive organ);
 * Misc: Most abundant soil-dwelling arthropods; Appear to have evolved in cold climate;

Diplura (diplurans)
Chewing/biting mouthparts; Antennae longer than head w/ 10 bead-like segments; Lack Eyes; Wingless; 3 pairs of walking legs, regenerate lost legs through molts, Tarsi 1 segmented; Move thru soil by pushing with wormlike movements or using tunnels/crevices; Abd 10 visible segments, Paired cerci at rear (either pincer like in appearance OR long & slender {means they’re herbivores}), small, eversible vesicles on the ventral side of first 7 abdominal segments that help regulate the body's water balance, possibly by absorbing moisture from the environment; Sexes are separate & fertilization is external, Males produce sperm packets (spermatophores) & glue them to the substrate on the end of little stalks, Females use their genital opening to gather spermatophores & then lay their eggs on little stalks inside a crevice or small cavity in the ground; Molt many times throughout life; 2-5mm; Whitish in color, cerci usually darker; Elongated body; Some cerci adapted to break off if mishandled (autotomy); Not pests, Important decomposers; Found- grassy places in New Zealand, Australia, Live in moist soil, leaf litter, or humus; Common (but seldom seen because of size & reclusive habits); Predators OR herbivores if have long cerci; Wide variety of other soil-dwellers, including collembola, mites, symphyla, insect larvae, & even other diplurans OR vegetable debris & fungal mycelia (animal prey preferred); Among most primitive hexapods; “Diplo” – two, “Ura” – tails;
 * Head: Chewing/biting mouthparts; Antennae longer than head w/ 10 bead-like segments; Lack Eyes;
 * Thorax: Wingless; 3 pairs of walking legs, regenerate lost legs through molts, Tarsi 1 segmented; Move thru soil by pushing with wormlike movements or using tunnels/crevices;
 * Abdomen: Abdomen with 10 visible segments, Paired cerci at rear (either pincer like in appearance OR long & slender {means they’re herbivores}), small, eversible vesicles on the ventral side of first 7 abdominal segments that help regulate the body's water balance, possibly by absorbing moisture from the environment;
 * Sexual Dimorphism: Sexes are separate & fertilization is external, Males produce sperm packets (spermatophores) & glue them to the substrate on the end of little stalks, Females use their genital opening to gather spermatophores & then lay their eggs on little stalks inside a crevice or small cavity in the ground;
 * Life Cycle: Molt many times throughout life
 * Misc Anatomy: 2-5mm; Whitish in color, cerci usually darker; Elongated body; Some cerci adapted to break off if mishandled (Autotomy);
 * Human Impact: Not pests, Important decomposers;
 * Habitat: Grassy places in New Zealand, Australia, Live in moist soil, leaf litter, or humus; Common (but seldom seen because of size & reclusive habits);
 * Diet: Predators OR herbivores if have long cerci; Eat Wide variety of other soil-dwellers, including collembola, mites, symphyla, insect larvae, & even other diplurans OR vegetable debris & fungal mycelia (animal prey preferred);
 * Explanation of Name: “Diplo” – two, “Ura” – tails;
 * Misc: Among the most primitive hexapods

Thysanura (bristletails, silverfish)
Short mandibles, unspecialized mouthparts; Antennae long, thread-like, & multi-segmented; Compound eyes small or absent; Wingless; Abdomen with ten complete segments, 11th segment elongated to form a median cadual filament; 3 cerci (nearly as long as median cadual filament), styliform appendages located on abdominal segments 7-9; Elaborate Courtship ritual (male spins a silken thread between the substrate & a vertical object then depositsa sperm packet beneath the thread & gets a female to walk through. When her cerci contact the silk thread, she picks up the spermatophore with her genital opening. Sperm enters her reproductive system & she eats the empty sperm packet; Relatively long lived, 3 years; Less than 1 cm long; Sliver scales covering bodies; Flattened, elongated, oval-shaped; Can cause extensive damage to household goods (wallpaper paste, book bindings, starch, cardboard, paper products); Domestic & sylvan (wooded) habitats worldwide; Common; Scavengers/browsers; Eat many things- algae, lichens, or starchy vegetable matter…; Hide under stones/leaves during the day & emerge after dark for food; "thysano-" fringed, ‘ura’- tail;
 * Head: Short mandibles, unspecialized mouthparts; Antennae long, thread-like, & multi-segmented; Compound eyes small or absent;
 * Thorax: Wingless
 * Abdomen: Abdomen with ten complete segments, 11th segment elongated to form a median cadual filament; 3 cerci (nearly as long as median cadual filament), styliform appendages located on abdominal segments 7-9;
 * Sexual Dimorphism: Elaborate Courtship ritual (male spins a silken thread between the substrate & a vertical object then depositsa sperm packet beneath the thread & gets a female to walk through. When her cerci contact the silk thread, she picks up the spermatophore with her genital opening. Sperm enters her reproductive system & she eats the empty sperm packet;
 * Life Cycle: Relatively long lived, 3 years;
 * Misc Anatomy: Less than 1 cm long; Sliver scales covering bodies; Flattened, elongated, oval-shaped;
 * Human Impact: Can cause extensive damage to household goods (wallpaper paste, book bindings, starch, cardboard, paper products);
 * Habitat: Domestic & sylvan (wooded) habitats worldwide; Common; Hide under stones/leaves during the day & emerge after dark for food;
 * Diet: Scavengers/browsers; Eat many things- algae, lichens, or starchy vegetable matter…;
 * Explanation of Name: "thysano-" fringed, ‘ura’- tail; refers to the long, fringed filaments on the abdomen