AN ENTOMOLOGIST’S DICTIONARY

abdomen

the part of the body behind the thorax (human abdomens are usually referred to as tummy or belly). It is the largest of the three body segments of an insect (the other parts being the head and the thorax).

antennae (singular: antenna)

a pair of sensory appendages on the head, sometimes called ‘feelers’. They are used to sense many things including odour, taste, heat, wind speed and direction.

arthropod

means ‘jointed leg’ and refers to a group of animals that includes insects (known as hexapods), crustaceans, myriapods (millipedes and centipedes) and chelicerates (spiders, scorpions, horseshoe crabs and their relatives). Arthropod bodies are usually in segments, and all arthropods have an exoskeleton and are invertebrates.

beetle

one type (or ‘order’) of insect with the front pair of wing-cases modified into hardened elytra. There are more different species of beetle than any other animal on the planet.

chitin

the material that makes up the exoskeletons of most arthropods, including insects. Chitin is one of the most important substances in nature.

coleoptera

the scientific name for beetles.

coleopterist

a scientist who studies beetles.

compound eyes

can be made up of thousands of individual visual receptors, and are common in arthropods. They enable many arthropods to see very well, but they see the world as a pixelated image – like the pixels on a computer screen.

DNA (deoxyribonucleic acid)

the blueprint for almost every living creature. It is the molecule that carries genetic information. A length of DNA is called a gene.

double helix

the shape that DNA forms when the individual components of DNA join together. It looks like a twisted ladder.

elytra (singular: elytron)

the hardened forewings of beetles that serve as protective wing-cases for the delicate, membranous hind wings underneath, which are used for flying. Some beetles can’t fly; their elytra are fused together and they don’t have hind wings.

entomologist

a scientist who studies insects.

exoskeleton

an external skeleton – a skeleton on the outside of the body, rather than on the inside like mammals. Insects have exoskeletons made largely from chitin. The exoskeleton is very strong and can be jam-packed with muscles, meaning that insects (especially beetles that have extremely tough exoskeletons) can be very strong for their size.

habitat

the type of area in which an organism lives – for example, a stag beetle’s habitat is broad-leaved woodland.

insect

in the ‘class’ insecta, with over 1.8 million different species known and more to discover. Insects have three main body parts: the head, thorax and abdomen. The head has antennae and a pair of compound eyes. Insects have six legs and many have wings. They have a complex life cycle called metamorphosis.

invertebrate

an animal that does not have a spine (backbone).

larvae (singular: larva)

immature insects. Beetle larvae are sometimes called grubs. Larvae look completely different to adult insects and often feed on different things than their parents, meaning that they don’t compete with their parents for food.

mandibles

beetles’ mouth parts. Mandibles can grasp, crush or cut food, or defend against predators and rivals.

metamorphosis

means ‘change’. It involves a total transformation of the insect between the different life stages (egg, larvae, pupae and adult or egg, nymphs and adult). For example, imagine a big, fat, cream-coloured grub: it looks nothing like an adult beetle. Many insects (including beetles) metamorphosize inside a pupa or cocoon: they enter the pupa as a grub, are blended into beetle soup, re-form as an adult beetle and break their way out of the pupa. Adult beetles never moult and, because they are encased in a hard exoskeleton that doesn’t stretch or grow, they can never grow bigger. Therefore, if you see an adult beetle, it can never grow any bigger than it is.

palps

a pair of sensory appendages, near the mouth of an insect. They are used to touch/feel and sense chemicals in the surroundings.

setae (singular: seta)

tiny hair-like projections covering parts of an insect’s body. They may be protective, can be used for defence, camouflage and adhesion (sticking to things) and can be sensitive to moisture and vibration.

species

the scientific name for an organism; helps define what type of organism something is, regardless of what language you speak. For example, across the world, Baxter will be known as Chalcosoma caucasus. However, depending on what language you speak, you will call him a different common name. The species name is always written with its ‘genus’ name in front of it and it is always typed in italics, with the genus starting with a capital letter and the species all in lower-case type. If you are writing by hand, it should all be underlined instead of italicized. See ‘Taxonomy’.

stridulation

a loud squeaking or scratching noise made by an insect rubbing its body parts together to attract a mate, as a territorial sound or warning sign.

taxonomy

the practice of identifying, describing and naming organisms. It uses a system called ‘biological classification’, with similar organisms grouped together. It starts off with a broad grouping (the ‘kingdom’) and gets more specific, with the species as the most specific group. No two species names (when combined with their genus) are the same: kingdom → phylum → class → order → family → genus → species. This system avoids the confusion caused by common names, which vary in different languages or even different households. For example, Baxter is a species of rhinoceros beetle: some people may call him an Atlas beetle, Hercules beetle or unicorn beetle, and there are lots of different species of rhinoceros beetle. So how do we know what Baxter really is? If you use biological classification, you can classify Baxter as: kingdom = animalia (animal) → phylum = arthropoda (arthropod) → class = insecta (insect) → order = coleoptera → family = scarabaeidae → genus = Chalcosoma → species = caucasus. But all you really need to say is the genus and species, so Baxter is: Chalcosoma caucasus.

thorax

the part of an insect’s body between the head and the abdomen.

transgenic

an animal can be described as transgenic if scientists have added DNA from another species.