Beetles (order Coleoptera) are exceedingly useful insects. Some bury the dung of herbivours that would otherwise accumulate and threaten large areas of pastureland and natural areas. Some beetles are pollinaters. Some play a role as minature vultures, consuming carcasses. Others eat the parasitic insects of birds and mammals. Others predate crop pests and are very useful in biological control programmes. Some delight us with their diversity and beauty. Some of course just fill in another part in a food chain. Beetles are also exceedingly numerous, with over 250,000 species identified by science, but despite the huge numbers you'll generally have to search to find one. Most live very unobtrusive lives, concealing themselves from view and many are nocturnal. Beetles are very varied in size, shape and colour, but there are some common features as listed below.

• The fore wings are modified into elytra or wing-cases
• If present, the hind wings are membranous and folded below the elytra
• Tarsi (legs) are five-jointed
• Metamorphosis is complete¹

Classification

Scientists often like to but things into groups so it's easier to see what is more closely related to what. Beetles are no exception and this entry on taxonomy helps explain the terms used in their classification. Beetles (Coleoptera) are an order of the insects (Insectica) and are split into two sub-orders; Adephaga (the carniverous beetles) and Polyphage (the omniverous beetles). Below is a guide to the two sub-orders and the main families in each.

Adephaga

The larvae and the adults of Adephage are both predaceous, though some are more active than others.

Carabidae is a large family and indeed is divided into two sub-families; the Tiger Beetles (Cicindelinae) and the Ground Beetles (Carabinae). Tiger Beetles are more sluggish than most in the sub-order, choosing to hide upright in a hole in the ground with its jaws protruding and snatches any passing prey. Tiger Beetles are also for the most part very colourful beetles. Ground beetles are very active and both larvae and adults are active predators.

Dytiscidae

Gyrinidae