Aquatic Entomology and Habitats Review

Comprehensive vocabulary terms covering aquatic insect habitats (lentic, lotic, wetlands), biological structures, life history, and functional feeding groups based on lecture notes.

Lentic

Refers to still or standing water habitats, which are usually open (non-vegetative).

Littoral zone

The area near the shore of a lentic habitat that contains rooted vegetation.

Open Water Zone

The deep area of a lake or pond where there is no rooted vegetation.

Benthic zone

The lake bottom where sediment is often anoxic; the primary habitat for many stream insects.

Surface Film

Area where water sticks together (cohesion) and to other surfaces (adhesion), creating a net inward attraction that supports small organisms.

Plankton

Floating organisms that are dependent on water currents, such as Chaorborus Fly Larvae.

Nekton

Swimmers that can navigate at will through the water column, such as predaceous diving beetles.

Pleuston

Organisms living directly on or underneath the water surface, including water striders and mosquitoes.

Benthos

Organisms that live on the bottom of a water body, such as stoneflies.

Perennial Stream

A lotic habitat where water flows all the time.

Intermittent Stream

A lotic habitat where flow occurs only some of the time, often in a cyclical pattern.

Ephemeral Stream

A lotic habitat that flows rarely.

Silt

Inorganic substrate often dominated by microbes that is anoxic and difficult for organisms to burrow into.

Woody Debris (Snags)

Organic substratum in streams used as a surface for attachment, particularly in silty and sandy streams.

Cascades

A stream habitat with a steep gradient where water falls from boulder to boulder.

Rapids

A stream habitat with a moderate gradient featuring deep water, boulders, and cobble with turbulent, fast-moving water.

Riffle

A stream habitat with a low gradient, consisting of cobble and gravel in shallow, fast water.

Run

A low gradient stream habitat with shallow to deep water, a uniform substrate (like bedrock or sand), and fast, even flow.

Hyporheic zone

The transition zone below the surface of flow where stream water and underground flow mix, extending up to $20\,cm$ below the surface.

Hydroperiod

The specific period of water inundation in a wetland, ranging from temporary to complete inundation.

Marshes

Wetlands dominated by herbaceous plants that are frequently or continuously inundated; insect communities here are similar to lake littoral zones.

Swamps

Wetlands dominated by woody vegetation with anoxic clay or silt sediments; they generally have lower insect diversity than marshes.

Vernal Pool

A temporary pool formed by a depression, most often applied to dry climates.

Riparian zone

The land surrounding a river, stream, or other waterbody where adults of aquatic insects often emerge.

Cuticle

The layer of an insect's exoskeleton that acts as an internal brace for muscle attachment and can be hard or membranous.

Sclerites

Hard sections of the exoskeleton that form plates on the body, produced by the cross-linking of protein chains.

Labrum

The upper lip of an insect, connected to the clypeus, used to hold food in place.

Mandibles

Mouthparts held laterally used for crushing or chewing; they may be modified for piercing or scraping.

Maxilla

Lateral mouthparts used to hold or tear food, equipped with palps for touch and taste.

Labium

The lower lip of an insect used to hold or tear food, which also possesses palps for touch and taste.

Hypopharynx

An insect's tongue, which helps in swallowing food and is often associated with salivary glands.

Pneustic respiration

Respiration using a fixed air source like a bubble or plastron, where air passes through spiracles surrounded by hydrofuge hairs.

Apneustic respiration

Respiration that uses cutaneous diffusion or gills to increase surface area for oxygen and carbon dioxide exchange.

Voltinism

A term describing the number of generations an organism has per year.

Multivoltine

Organisms that complete multiple generations per year.

Univoltine

Organisms that complete one generation per year.

Semivoltine

Organisms that complete one generation over multiple years.

Ametabolous

A life cycle where the egg develops into an instar that looks like a small adult, seen in Collembola.

Hemimetabolous

A life cycle (Egg -> Nymph -> Adult) where juveniles (nymphs) resemble adults but lack wings and sex organs; seen in Ephemeroptera and Odonata.

Holometabolous

A life cycle (Egg -> Larva -> Pupa -> Adult) with an inactive pupal stage where the larva does not resemble the adult; seen in Coleoptera and Diptera.

Diapause

A pause in embryo development due to unfavorable conditions like temperature, water levels, or photoperiod.

Grazers (Scrapers)

Functional feeding group that consumes autotrophs by scraping algae off substrates, including some Lepidoptera and Ephemeroptera.

Shredders

Functional feeding group that eats coarse particulate matter like leaves and wood, deriving nutrition from associated microbes.

Collector Gatherers

Insects that eat fine particulate matter deposited on the benthos.

Filter-Feeders (Collector-Filterers)

Passive feeders that use flowing water to bring in food particles, such as Blackfly and caddisfly larvae.

Burrower

A functional habitat where insects inhabit fine sediment or roots and may construct burrows for predation or oxygen circulation.

Climber

Insects adapted for vertical movement along detritus or vascular plants, such as many Odonata.

Clinger

Insects with adaptations like fixed retreats, large claws, or dorso-ventral flattening to stay on substrates in fast-moving water.

Sprawler

Insects that stay on top of fine sediments or leaves with modifications to keep their body and respiratory structures free of silt.

Skater

Insects adapted to the water surface using hydrophobic hairs or chemicals, such as Hemiptera.

Swimmer

Insects with strong swimming abilities facilitated by streamlining or swimming hairs.