Glossary

Abdomen: the third of the three basic body regions in insects

Afferent and efferent nerves: Afferent nerves carry nerve signals from sensory organs to the brain and central nervous system. Efferent nerves work in the other direction, carrying signals from the central nervous system out to other body parts, such as muscles.

Allele: One of two or more forms of the same gene, found at the same position on a chromosome. Alleles are responsible for genetic diversity within a species.

Antennae: sensory appendages on the head, mainly used to detect odors

Appendages: jointed structures attached in pairs to certain body-segments, with variable functions (includes legs and antennae)

Aquatic: adapted to live in water

Cerci: appendages on the last abdominal segment, often used during copulation

Chromosomes: long strands of DNA, each made up of many genes, found in the nucleus of each cell in an animal’s body; they come in pairs and all insects of a certain species have the same number of pairs (e.g., the fruit fly Drosophila melanogaster has four pairs of chromosomes)

Chrysalis: the pupa of a butterfly

Cocoon: a protective case of silk around a pupa, produced by some moths and other insects

Compound eyes: a pair of large eyes, formed from multiple ommatidia and found on the heads of most insects

Crop: the first part of the digestive tract, where swallowed food is stored

Crop pest: any plant-eating insect that does significant damage to plants cultivated for food

Cuticle: the outer “shell” or exoskeleton of an insect; some internal organs are also cuticle-lined

Dorsal vessel: a central vessel that pumps hemolymph, functioning similarly to the heart in vertebrates

Ecology: the study of organisms and their environment as a functioning system

Ecosystem: the community of organisms within a particular habitat, and their interrelationships

Elytra: the modified, thickened forewings (“wing cases”) of beetles

Estivation: prolonged period of inactivity through hot and dry summer weather

Eusocial insects: species that live communally, with most individuals being nonbreeding “workers” acting to maintain the colony and support the breeding female or pair

Fat-body: an internal structure where fat is stored; also involved in detoxification and other functions similar to those carried out by the liver in vertebrates

Ganglia: a bundle of nerve cells, functioning like a miniature brain

Genes: short sections of DNA that each provide the “instructions” for making a particular kind of protein

Gills: structures that are used to extract oxygen from water

Halteres: club-shaped structures found in Diptera (the true flies), formed from modified hind wings

Head: the first of the three basic body regions

Hemimetabolous: describes an insect that goes through incomplete metamorphosis, changing from larva to adult with no pupal stage

Hemocoel: the internal body cavity of an insect, filled with hemolymph

Hemolymph: the fluid that fills an insect’s hemocoel, used to transport metabolites

Hibernation: passing the winter in an inactive state with greatly lowered metabolism

Holometabolous: describes an insect that goes through complete metamorphosis—it passes through four life stages: egg, larva, pupa, and imago/adult

Imago: another word for an adult winged insect

Instar: growth stages between the molts in an insect larva

Larva: an insect that has yet to metamorphize to adulthood; the growth life stage

Malpighian tubules: structures connected to the gut that help maintain the correct fluid balance

Mandibles: the jaws or biting mouthparts

Metamorphosis: transformation from larval form to adult form

Migration: traveling (regularly and predictably) from one region to another at a particular time of year, to avoid inclement weather or temperatures

Mouthparts: appendages on the head, used for feeding

Mutation: During the process of copying chromosomes prior to cell divisions, sometimes errors occur, and the genes that make up the new chromosome copy are not identical to those in the original. This is a genetic mutation, and if it occurs during the formation of a sperm or egg cell that goes on to become an embryo, it will be propagated in all the cells of that embryo.

Nymph: an alternative name for the larva of a hemimetabolous insect

Ocelli: small simple eyes, found in addition to compound eyes in some insects

Ommatidia: the light-sensing structures from which a compound eye is formed

Parasite: any animal that lives permanently (in at least one of its life stages) on another animal’s body and consumes its body tissues, such as blood or skin

Parasitoid: an insect that lays its eggs in or on a living host’s body; the larvae will eat the host, eventually killing it

Predator: an animal that catches and kills other animals for its food

Prey: animals that are killed by predators

Pupa: an inactive life stage in between larva and adult in holometabolous insects, during which metamorphosis takes place

Queen: a reproductive female in a nest or hive of eusocial insects

Segments: the individual body-sections of insects and other arthropods

Sequestering: The storing of substances from the diet in the body tissues, in an unchanged state. Some insects sequester toxic compounds from the plants they eat, making their own bodies poisonous to any predators that try to eat them.

Spiracles: holes in body-segments, used to take in oxygen and expel carbon dioxide

Subimago: a subadult, winged life stage unique to mayflies

Teneral: a newly or recently emerged adult insect, usually still soft-bodied and not ready to breed

Thorax: the second (middle) of the three basic body regions

Uniramous: of a body appendage, having only one branch—either a gill or a leg; some arthropods have biramous (two-branched) appendages, each comprising both a gill and a leg

Venation: the branching network of veins within an insect’s wing

Wings: membranous structures found in most adult insects, and used to provide power and lift for flight

Worker: a nonbreeding individual in a eusocial insect colony; its activities may include colony defense, nest maintenance, and collecting food