Insect antennae

Antennae function almost exclusively in sensory perception. Some of the information that can be detected by insect antennae includes: motion and orientation, odor, sound, humidity, and a variety of chemical cues.
The antennae are an insects primary, non-visual, sense organs, though in a few rare instances they have become adapted for other purposes such as seizing prey items ( i.e. the larva of Chaoborus sp. {Diptera}) or holding females during mating (i.e. the males of Meloe sp. {Coleoptera}) Not all insects possess antennae, they are absent from the Protura.

In most insects the antennae possesses a mechanosensory organ on the pedicel (the second antennal segment) called 'Johnston's organ' and, normally, only the basal antennal segment contains intrinsic muscles. However in two orders (Diplura and Collembola) the antennae lack a 'Johnston's organ' and all but the last segment contains intrinsic muscles, thus allowing far greater controlled movement of the antennae as is demonstrated by the rolling and unrolling of the antennae observed in the Collembola Tomocerus longicornus.

Antennae come in a wide variety of shapes and sizes, generally the first segment is known as the 'scape', second segment as the 'pedicel' and the rest as the flagellum. It is quite usual that the males of a species have more elaborate antennae than the females, this is because it is normally the males who have to find the females. The greater the surface area of the antennae the more dilute scents they can detect, thus male insects with feathery antennae, such as those seen in many moths, are far more sensitive than the purely filamentous ones of crickets and cockroaches.

The antennae are a pair of sense organs located near the front of an insect's head capsule. Although commonly called "feelers", the antennae are much more than just tactile receptors. They are usually covered with olfactory receptors that can detect odor molecules in the air (the sense of smell).

Many insects also use their antennae as humidity sensors, to detect changes in the concentration of water vapor. Mosquitoes detect sounds with their antennae, and many flies use theirs to gauge air speed while they are in flight.