Glossary

A

The third major section of the insect situated behind the head and thorax. Note that the thorax bears the legs and wings.

Aboral:

A structure located away from the mouth.

Absorption:

To suck in. The incorporation of a lesser substance by a larger and different substance e.g. the absorption of water by a sponge.

Adductor Muscles:

Muscles that bring the outer most part of an appendage toward the body.

Adhesive Disk:

A circular pad on the body that forms a seal or sticking contact with another surface without bonding permanently.

Anamorphosis:

The immature insect looks similar to the adult insect, but has fewer segments on the abdomen. These segments are gained through the moulting process.

Annulation:

Ring-like markings on the outside of the body that do not form individual segments internally.

Antenna:

(pl. antennae). A pair of appendages on the head that have several segments. Antennae are used to sense the environment either through sound, touch or smell.

At or toward the front end of the insect.

Anticoagulant:

A chemical injected into a host to prevent blood clots forming and to allow continuous feeding for the parasite.

Apex:

The pointed end of the abdomen.

Apodous:

An organism without feet, or legless.

Appendages:

External features attached or appended to the body e.g. legs, wings, antennae.

Appendix Dorsalis:

The middle appendage on the tip of the abdomen found in Silverfish, Bristletails and some aquatic insects.

Apterous:

Without wings.

Aquatic:

Organisms that live in freshwater. Organisms living in salt water are called marine.

Arthropod:

The Phylum Arthropoda consists of organisms with distinct body segmentation, jointed appendages and an exoskeleton.

Axis:

An imaginary central line of a structure that determines orientation or shape.

B

Basal:

At or towards the base, or towards the point of attachment e.g. where wings are attached to the thorax this is the basal part of the wing.

Bilateral Symmetry:

When an imaginary line is drawn down the centre of the body, the right half is a mirror copy of the left half.

Biological Control:

The use of predators, parasites or pathogens to control pest insect populations.

Blood Circulatory System:

The movement of blood through the body cavity, appendages and cells of the organism.

Brackish:

Brackish water occurs at the interface of freshwater and saltwater when they meet.

Budding:

Budding is a form of asexual reproduction where offspring grow out from the body of the parent. Found mainly in Hydra.

C

Capitate:

Enlarged and globular, head-like.

Carnivorous:

Eats the flesh of animals such as other insects, fish, reptiles, etc.

Cerci:

A pair of appendages on the second last segment of the abdomen that are used to sense the environment through touch.

Chitin:

A major component of the insect "skin" made from polysaccharides. Chitin is usually darkened and gives the skin or cuticle strength.

Choanocyte:

A flagellated cell that lines the body cavity of a sponge and is characterized by a collar of cytoplasm around the flagellum. Also called a collar cell.

Cilium:

(Pl. cilia). Hairs in a line along a margin or scattered over the surface of an organism. For single-celled eukaryotes, cilia are essential for locomotion of individual organisms. In multicellular organisms, cilia function to move fluid or materials past an immobile cell. Cilia generate water currents to carry food and oxygen past the gills of clams and transport food through the digestive systems of snails.

Claw:

A sharp, curved structure at the end of an appendage.

Collophore:

A tube on the abdomen of Collembola. The tube is thought to glue the insect to the ground after it has been sprung in the air. It is also believed that the collophore is involved in the transfer of water and minerals to the insect from the ground and from the insect as excrement.

Colonial:

A colony is a group of individuals of the same species living in close association with one another.

Compound Eye:

A compound eye is made up of several, often thousands, single visual cells that act together as a single eye. However, the image created by the eye is not a single image, but made up of overlapping images from each lens.

Constricted Abdomen:

In ants, bees and wasps the first two segments of the abdomen are narrowed and much smaller than the other segments of the abdomen. The constriction gives the insect the appearance of having a waist.

Contractile:

Capable of being drawn together or toward the body.

Copulation:

Being joined or bonded together during sexual intercourse.

Cosmopolitan:

Organisms that are found throughout the world.

Coxa:

The first segment of the leg insect. The coxa is attached to the body and is called the basal segment of the leg.

Crochets:

Curved spines or hooks on the prolegs. Prolegs are located on the abdomen of some larvae but are structurally different from legs on the thorax.

Crustacean:

The Class Crustacea contains aquatic organisms that have a hard shell and many jointed legs. Some examples include shrimps, yabbies and crabs.

Crypsis:

Camouflaged by resembling the environment in which it is found, e.g. stick insects look like twigs and sticks.

Cursorial:

Legs that are adapted for running. They are typically long and tapered.

Cuticle:

The external covering of the insect forming the exoskeleton. The cuticle is formed by secretions from the epidermis comprising chitin and proteins in several different layers.

D

Detritus:

The broken down and fragmented pieces of rocks, plants, bone, feathers, skin, etc.

Digestive Enzymes:

Chemicals used to breakdown food particles into smaller pieces for digestion. Digestive enzymes are usually contained within the stomach, but may be secreted directly onto food to produce a liquid for lapping and sucking.

Digestive Tract:

A tube that runs from the mouth to the anus, where food is digested.

Dimorphism:

A morph has a particular form. Within a species there maybe individuals that possess either of two distinct forms e.g. size, shape or colour. For example, locusts are green in their normal state, but are brown when in swarms, hence two morphs exist in the one population.

Dorsal:

On the top or upper surface of the insect.

Dorsoventrally Flattened:

Flattened from top to bottom. When viewed from the side the insect is very thin.

E

Ectoparasite:

A parasite that lives and feeds externally on the host. An obligate ectoparasite can only live on the host and will die if removed. Lice are obligate ectoparasites, the only means of transfer to another host is for contact between hosts. Fleas are not 'obligate' ectoparasites as the larvae and pupae do not live on the host but the adult does. Fleas are also able to transfer to new hosts by jumping onto grass, carpet, etc. and waiting for a new host to arrive.

Elytron:

(pl. elytra). The hard forewing of beetles that protects the hind wing.

Endemic:

An organism that is native to an area and has not been introduced.

Endoparasite:

A parasite that lives within the host. Some wasps lay their eggs in caterpillar bodies after piercing them with their needle-like ovipositor. The larvae hatch from the eggs and feed on the organs of the caterpillar host. These wasps are effective biological control agents in crops that are attacked by caterpillar pests.

Entomophobia:

A fear of insects.

Epithelium:

A layer of cells that covers a surface (e.g. skin), or lines a cavity (e.g. the inside of the mouth).

Estuarine:

An organism that inhabits an estuary (an inlet where a river or creek meets the sea).

Eversible:

Something that can be everted or turned outward or inside out.

Excurrent Pore:

Sponges have pores that allow water to flow from the inside out. Pores that allow water to flow from the outside in are called Incurrent Pores.

Exoskeleton:

The hardened covering (skin) of the insect. Muscles are attached to the internal wall of the exoskeleton. The exoskeleton is one of the defining features of all arthropods, e.g. spiders, scorpions, lobsters, etc.

Exotic:

An organism that is not native to an area and has been introduced.

Extensible:

A structure that can be extended, stretched or drawn out.

F

Faeces, faecal matter:

The solid waste products removed from the body after digestion; excrement.

Family:

One of the levels in the hierarchy of naming organisms. Family level is the grouping above Genus and Species.

Femur:

(pl. femora). The third segment of the insect leg following the coxa and trochanter.

Filament:

A long, thread-like appendage.

Filiform:

A filiform antenna is thread-like with long cylindrical segments that are similar in diameter.

Filter Feeder:

An organism that consumes large amounts of water to sieve or filter out the food particles for ingestion. Some organisms feed while moving through water, while others use gills or appendages to move water over the filters to gather food.

Forewings:

The front or anterior pair of wings located on the second segment of the thorax.

Freshwater:

Water that is not salty.

Furcula:

A small, forked appendage that in Collembola is used for springing the insect into the air.

H

Haltere:

The modified hind wing of flies and mosquitoes (Order Diptera). The halteres act as a balancing organ to maintain stable flight. The halteres move up and down, while the forewings move in figure 8 pattern.

Hamuli:

A row of hooks along the margin of the hind wing that couples the hind wings and forewings together for flight.

Hemelytron:

(pl. hemelytra). The forewing of some bugs in the Order Hemiptera have a thickened basal half and a membranous apical half.

Hemimetabolous:

The development of nymph to adult in which the nymph is similar in appearance to the adult but wing buds and sexual organs develop through moulting.

Herbivore:

Organism that feeds on plant material.

Hind wings:

The rear or posterior pair of wings located on the third segment of the thorax.

Holometabolous:

The development of larva to adult in which the larva is different in form to the adult and undergoes a dramatic change in the pupal stage e.g. caterpillar to butterfly.

Host:

An organisms that is used or feed on by a parasite.

I

Imago:

The adult insect.

Immobile:

Not capable of movement or locomotion.

Incurrent Pore:

Sponges have pores that allow water to flow from the outside of the organism into it.. Pores that allow water to flow from the inside out are called Excurrent Pores.

Insects:

The Class Insecta contains animals with three body segments (head, thorax and abdomen), three pairs of legs and an exoskeleton. It is also characterised by a complex life cycle involving metamorphosis.

Instar:

The immature insect between moults or the period between moults.

Integument:

The outer layer or covering of an organism.

Intestine:

The part of the digestive system where food absorption is completed and excrement is formed for expulsion.

Introduced:

An organism that does not naturally occur in a region and has been placed there through human intervention.

Invertebrates:

Organisms that do not contain a backbone. All arthropods and hence all insects are classified in the Phylum Invertebrata.

Irregular Symmetry:

An organism that has irregular symmetry does not have an axis through which it can be cut and the two sides are not mirror images of one another.

L

Labium:

The 'lower lip' forming the floor of the mouth.

Labrum:

The 'upper lip' forming the roof of the mouth.

Larva:

(pl. larvae). The immature insect that emerges from the egg and is different in form to the adult e.g. caterpillar. An immature insect that is similar in form to the adult is called a nymph.

Lateral:

A structure or movement to the side. A side view.

Laterally Compressed:

Flattened from side to side. When viewed from above the insect appears thin.

Ligament:

Tissue that connects segments and holds organs and muscles in place.

Locomotion:

The progressive movement from one place to another.

M

Macroinvertebrate:

An invertebrate organism that can be seen with the human eye and without the aid of a microscope.

Maggot:

The larval stage of flies (Order Diptera) that is without legs and has a reduced head.

Mandibles:

The jaws. The mandibles can be highly modified and range from jaw-like structures for biting and chewing to long thread-like appendages for piercing and sucking.

Marine:

Organisms that are associated with salt water environments.

Maxillary Palps:

Palps located on the mouthparts that range in size from 1-7 segments. Palps help to move food to the mouth.

Median:

In or at the middle.

Membranous:

Thin and semi-transparent tissue, usually of the wings.

Mesothorax:

The second or middle segment of the thorax which bears the middle legs and forewings.

Metamorphosis:

The change in form from immature to adult that is often abrupt and requires major changes in tissues and organs e.g. caterpillar to winged butterfly. This usually occurs in the pupal stage.

Metathorax:

The third or posterior segment of the thorax which bears the hind legs and hind wings.

Mimic:

An organism that resembles another species or inanimate object in order to gain some benefit such as protection from predation. The resemblance can be in size, shape, colour or habits.

Moniliform:

Moniliform antenna resemble a chain of beads i.e. each segment is round and uniform in size and shape.

Motile:

Able to move or moving.

Moult:

The casting off of old exoskeleton and the formation of new exoskeleton in order for the insect to grow in size.

Mouthparts:

Appendages on the head used specifically for gaining and processing food.

O

Ocellus:

(pl. ocelli). Simple eyes that are usually grouped in three on the top of the head in front or between the compound eyes. Ocelli do not form images but are sensitive to light.

Ootheca:

An egg case or protective surrounding for an egg mass.

Opaque:

Not transparent or not letting light pass through.

Order:

One of the levels in the hierarchy of naming organisms. Order level is the grouping above Family, Genus and Species.

Organ:

A differentiated group of cells that act together to perform a particular function e.g. nerve cells of the brain.

Ovipositor:

A tube from the abdomen of female insects used to lay eggs in or on a substrate e.g. soil, leaf surface.

P

Parapodia:

Small, primitive feet on the abdominal segments of Annelid worms. These are unsegmented legs that aid in locomotion.

Parasite:

An organism that lives in or on another organism (the host) or at the host's expense, but does not usually kill the host.

Pharynx:

The part of the digestive system between the mouth and oesophagous.

Pheromone:

A chemical secreted by one individual that affects the behaviour of another individual of the same species. Pheromones can play a role in aggregation, courtship, trail making and alarm behaviour.

Phylum:

One of the levels in the hierarchy of naming organisms. Phylum level is the grouping above Class, Order, Family, Genus and Species.

Phytophagous:

An organism that feeds on plant matter.

Piercing-sucking Mouthparts:

A tube is formed by a modification of the insect�s lower lip (labium). Inside the tube, modified mandibles form canals which allow an upward flow of liquid food and a downward flow of saliva. The mouthparts can pierce the outer surface of plants or skin and suck out the contents such as sap or blood.

Pincers:

Pointed grasping appendages on the tip of the abdomen in earwigs and proturans.

Plate:

A broad, flat surface on an organism.

Posterior:

At or toward the rear of the insect.

Predator:

An organism that kills and consumes another organism.

Primitive:

An feature that is simple or not modified.

Proboscis:

Mouthparts that are modified and elongated.

Prolegs:

An appendage that acts as a leg but is not attached to the thorax. Usually located on the abdomen of larvae such as caterpillars.

Prothorax:

The first or anterior segment of the thorax which bears the forelegs but not wings.

Protrusion:

Something that juts out from the surface of an organism e.g. bump, bulge, lump, spike, etc.

Pseudoculi or Pseudocelli:

Sense organs found on the body of Order Collembola and Order Protura.

Pupa:

(pl. pupae). The inactive stage between larva and adult in which major morphological changes take place e.g. the development of wings and sex organs. In moths and butterflies the pupa is also called a chrysalis.

R

Radial Symmetry:

A rounded organism that can be cut through the centre at any point (such as spokes on a wheel) and a mirror image of the two parts occurs.

Raptorial:

Legs with opposing spines used to seize and impale prey.

Reniform:

Kidney-shaped.

Retracted:

A structure that is drawn back into the body e.g. tentacles of a sea anemone retract when touched.

Rhynchocoel:

A rhynchocoel is a sheath that holds the proboscis when not in use. The rhynchocoel lies above the alimentary canal which is part of the digestive system.

Robust:

Describes structures or appendages that appear stout or thickened.

Rostrum:

A snout-like elongation of the head that bears the mouthparts.

S

Saline:

Water that is salty or contains salt.

Scales:

On moths and butterflies, scales are modified setae (hairs) that are flattened. Scales have pigment as well as ridges and grooves that reflect and refract light to produce the varying colours on the wings.

Sclerotised:

Hardened in particular areas by laying down cuticle substances other than chitin.

Secrete:

To release a substance (a secretion) from a gland or pore.

Sedentary:

Organisms that remain in one place and do not move, they may also be sessile.

Segmented:

Composed of segments or rings around the body.

Sensory:

Structures such as antennae, setae and nerve cells that sense the environment in which the organism lives.

Sessile:

An organism that does not or cannot move.

Seta:

(pl. setae). A hair-like structure with sense cells at the base. Setae are used as sensory structures by organisms and can be long and hair-like or flattened scales.

Sheath:

A protective outer structure that encloses another structure.

Simple Eyes:

See ocellus.

Solitary:

Living or existing alone.

Species:

A group of individuals that can interbreed and produce fertile offspring. In a Scientific or Latin name the species name is italicised or underlined. Abbreviations of sp. and spp. mean an unknown species within a genus and several unknown species within a genus, respectively.

Spine:

A sharp, pointed structure on the surface of a plant or animal.

Striation:

A long ridge or furrow along the surface of an organism.

Stylets:

A needle-like structure of the mouthparts used for piercing.

Sub-imago:

In the mayflies (Order Ephemeroptera ) there is a winged stage that requires one more moult before fully becoming an adult.

Sucker:

A disc that uses adhesion and surface tension to glue an organism to a substrate.

Symbiotic Protozoans:

Bacteria that live within the gut of termites (Order Isoptera) and breakdown cellulose. Symbionts both derive benefit from the relationship of the two different species.