Re: Ears on butterflies.

Marilynn,

Sorry this response took so long. I just joined the MSN, and I think I'm the only entomologist in the crew.

Insects have auditory organs that are analogous to ears. These structures, called tympana, are morphologically similar to the tympanic membrane within mammalian ears.

Not all insects have tympana. But because certain butterflies are a food source for bats, they have evolved high-frequency echolocating tympana. The Pyralidae (snout-moths) and members of the superfamily Geometroidea, including the Thyatiridae (thyatirid moths), Drepanidae (hook-tip moths), Geometridae (measuring worms), Epiplemidae, and Suraniidae, all have these organs on the anterior sternite (a subdividion of a sternum--the ventral plate of an abdominal segment) of the abdomen. The Noctuoidea (common moths) have tympana located ventrolaaterally on the metathorax (the third posterior segment of the thorax). All other butterflies and moths lack tympana.

Hope this helps, and sorry again for the wait.