Beetle anatomy

notable for their ability to grab adult flies, using

a combination of excellent vision and speed.

Many aquatic beetles use their compound eyes in

water, and the eyes of Gyrinidae (whirligig beetles)

are divided so that they can use the upper half to

scan the air above, while the lower half observes

the water below.

Unlike many insect orders, very few beetles

have secondary eyes, or ocelli, as adults. Most

Dermestidae (hide beetles) have a single ocellus

in the center of the head, which is a useful

identification character, and some Staphylinidae

have ocelli.

The mandibles, or jaws, are also attached to

the head, surrounding the mouth, with two sets

HEAD

Adult beetles have two large compound eyes,

except where they have been lost, for example

in numerous myrmecophilous (ant-associated),

subterranean, or troglobitic (cave-dwelling)

species of Carabidae, Dytiscidae, Staphylinidae,

Leiodidae, and so on, which inhabit near-

permanent darkness, and have no need for vision.

Many other beetles, especially those that are active

during the day, have excellent eyesight. Many

flower-feeding beetles, for example, can home in

on blossom of a particular kind and color from

high in the air, while jewel beetles (Buprestidae)

are extremely visually alert to the approach of

predators and are almost impossible to catch, even

with a net. Tiger beetles (Carabidae: Cicindelinae)

are visual predators and some are quick enough to

grab flies from the air. Diurnal dung-inhabiting

Staphylinidae of the genus Ontholestes are also

below | Manticora scabra (Carabidae) Named after

a mythological monster, this male African tiger beetle

uses asymmetrical mandibles for crushing large prey

and grasping a mate.

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