Freedom of Movement

Beetle

L: Beetle head with antenna removed showing socket
R: Scape of antenna fits in socket

Insects can use their antennae to sense objects using both tactile and chemo receptors. Insects with long antennae such as a male long-horned beetle use antennae to search for females. Their long antennae give them a wider search area. Nocturnal insects such as katydids, move at night and can sense objects far in front providing early warning of a lurking predator.

Antennae can be directed to collect information in a 360 degree arc. This movement is aided by the attachment of the antenna to the head. The head capsule forms sclerotized sockets for antennae. The proximal segment of the antennae, the scape, fits and the socket and is connected to socket by flexible resilin containing cuticle. Muscles inside the head rotate the scape in its socket.

The articulation of an insect antenna with its head is similar to the articulation of the leg with the thorax. (Legs and antennae are homologous in many ways). The proximal segment of the legs, the coxa, fits into a socket in the thorax that also forms a ball and socket joint. The ball and socket articulation of both antennae and legs gives the appendages freedom of movement.

About jjneal

Jonathan Neal is an Associate Professor of Entomology at Purdue University and author of the textbook, Living With Insects (2010). This blog is a forum to communicate about the intersection of insects with people and policy. This is a personal blog. The opinions and materials posted here are those of the author and are in no way connected with those of my employer.
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