Why are the antennae of moths and butteflies different?
Don Herbison-Evans,
Stella Crossley

male Pollanisus subdolosa, showing feathery antennae.
(Photo : courtesy of Laura Levens, Upper Beaconsfield, Victoria)

The antennae of Lepidoptera appear to be the main organs of smell. Many moth species fly only at night, or have flightless females, and so use pheromones for sexual attraction. Usually it is the female which emits the pheromone. which the males smell with the antennae. Their antennae have a feathery appearance.

male Pollanisus subdolosa, showing folded sensilla on the antennae.
(Photo : courtesy of Buck Richardson, Kuranda)

The lateral filaments on these antennae are called sensilla. The moths are able to fold or unfold these sensilla.

Butterflies fly in daylight, so in general appear to use sight rather than smell for sexual attraction, so do not need to use their antennae to find a mate. But many female butterflies check any plant thay land on, using their antennae and feet to see if it is a suitable plant on which to lay their eggs.

So the antennae of butterflies are different from those of moths. The antennae of butterflies have a bulge on the end of each antenna, like a small club.

female Delais nysa, showing clubbbed antennae.

Link to
Frequently Asked Questions about Caterpillars

Australian Butterflies
Australian Moths

(updated 22 December 2012, 5 January 2014)