Entomology External Anatomy, Diversity, and Classification Review

Flashcards covering external insect morphology, organ modifications, taxonomic order characteristics, taxonomy history, and light pollution impacts.

What is tagmosis in insects, and how many initial segments combine to form the three main tagmata?

Tagmosis is the amalgamation of segments into functional units; 20 initial segments combine to form the head (6 segments), thorax (3 segments), and abdomen (11 segments plus a telson).

What chemical polymer makes up the procuticle layer of an insect's integument?

Chitin, which consists of $\beta\text{-1,4}$ linked units of N-acetyl-D-glucosamine.

What process hardens the insect cuticle and makes cuticular proteins water-insoluble?

Sclerotization, which occurs through the dehydration of protein chains and/or the formation of phenolic bridges.

What is the tough, flexible, unsclerotized cuticle that allows body expansion in larvae and gravid females called?

Arthrodial membrane.

What structural differences distinguish cuticular spines, setae, acanthae, and microtrichia?

Spines are multicellular outgrowths; setae (hairs) are multicellular with specialized cells; acanthae are unicellular outgrowths; microtrichia are subcellular with multiple extensions per cell.

Which six embryonic segments form the head of an insect?

Segment 1: Ocular, Segment 2: Antennal, Segment 3: Labral, Segment 4: Mandibular, Segment 5: Maxillary, and Segment 6: Labial.

What is the hardness rating of insect mandibles on the Mohs scale, and what physical feat does this allow?

Mandibles have a hardness rating of 3 on the Mohs scale, enabling some insects to bore through metals such as copper, lead, tin, and zinc.

What are the three positions of insect mouthparts relative to the head capsule shown in this diagram?

(a) Hypognathous (pointing downward), (b) Prognathous (pointing forward), and (c) Opisthognathous (pointing backward).

Which specific segments of a generalized insect antenna are muscularized?

Only the scape and pedicel.

How are geniculate and aristate antenna types described structurally?

Geniculate antennae are elbowed, whereas aristate antennae feature an enlarged third segment bearing a bristle.

What central light-receiving structure within a compound eye ommatidium is formed by the retinula cells?

The rhabdom.

What specialized eye modification do adult male Mayflies possess for spotting flying females during mating dances?

Turban eyes.

What are the three regions of the insect thorax, and on which segments are wings typically found?

Prothorax, Mesothorax, and Metathorax; wings are found on the mesothorax and metathorax.

What is the propodeum in wasps and other apocritan Hymenoptera?

The first segment of the abdomen fused with the metathorax.

What are the six segments of a generalized insect leg listed in order from proximal to distal?

Coxa, Trochanter, Femur, Tibia, Tarsus, and Pretarsus.

What terms refer to insect leg adaptations specialized for digging, jumping, and swimming?

Fossorial (digging), Saltatorial (jumping), and Natatorial (swimming).

What structural difference distinguishes an elytron from a hemielytron?

An elytron is a completely hardened protective forewing (in Coleoptera), while a hemielytron has a leathery basal portion and a membranous apical portion (in Hemiptera).

What standard symbols represent the primary longitudinal veins in generalized insect wing venation?

Costa (C), Subcosta (Sc), Radius (R), Media (M), Cubitus (Cu), and Anal (A).

What wing-coupling mechanism hooks the forewings and hindwings together in Hymenoptera such as bees?

Hamuli.

What are the fleshy abdominal outgrowths bearing crochets in Lepidoptera and Hymenoptera larvae called?

Prolegs (or false legs).

What term describes the extreme swelling of the abdomen in a gravid termite queen due to unsclerotized membrane expansion?

Physogastry.

How many individual living insects are estimated to exist on Earth right now, and what is the ratio per human?

Approximately $10^{18}$ to $10^{19}$ living insects, corresponding to about 200 million insects for every human being.

Which five orders make up the "Big 5" insect orders, accounting for ~90% of all described insect species?

Coleoptera (Beetles), Lepidoptera (Moths & Butterflies), Hymenoptera (Sawflies, Wasps, Bees, Ants), Diptera (True Flies & Mosquitoes), and Hemiptera (True Bugs).

What is the largest family within Coleoptera, and how many described species does it contain?

Curculionidae (weevils), containing over 80,000 described species.

What quote is attributed to J.B.S. Haldane regarding insect diversity, and what 1982 study supported it?

J.B.S. Haldane remarked that the Creator has "an inordinate fondness for beetles"; this was supported by Terry Erwin's 1982 canopy fogging study finding 163 endemic beetle species in a single tropical tree species.

What terms denote developmental paths with no metamorphosis, incomplete metamorphosis, and complete metamorphosis?

Ametabolous (no metamorphosis), Hemimetabolous (incomplete metamorphosis), and Holometabolous (complete metamorphosis).

Which historical figures are credited with developing binomial nomenclature and introducing the concept of insect families?

Carl Linnaeus developed binomial nomenclature, and P.A. Latreille introduced the concept of insect families.

What standard suffixes designate an insect Superfamily, Family, Subfamily, and Tribe?

Superfamily ends in -oidea, Family in -idae, Subfamily in -inae, and Tribe in -ini.

What underlying flight reflex causes nocturnal insects to become trapped in orbiting, stalling, or inverting flight around artificial lights?

Dorsal flight response.

What lighting design strategy significantly reduces flying insect attraction compared to standard outdoor fixtures?

Fully recessing the bulb in addition to shielding.