The ability to detect sound
|As far as I know butterflies do not have the ability
to detect sound. However, many moths have ears. These ears are connected to nerve cells,
tuned to the usual range of bat frequencies (40 kHz). These ears make it possible for
moths to detect bats over a distance of 30 meters. Actually those moths hear bats before
bats detect their presence. If a bat is detected moths can react different, some just
change their flight direction, others close their wings and drop to the ground. Ears are
quite effective, for they reduce the success rate of bats approximately with 50 % in
comparison with moths without ears.
There are also moths which can produce sounds themselves. People used to believe that these sounds where used to confuse bats, so that the true echo is mistaken by the bats. Today the opinion is that these sounds are used as warning sounds, to make clear that those moths are distasteful to predators. The sounds produced by those moths clearly act as "warning coloration" does to visual predators.
The sound produced by this moth acts as its warning coloration does to visual predators