The interactions of insectivorous bats and their prey can be thought of as an evolutionary arms race. Bats began the race with the evolution of sophisticated, high frequency sonar with which they echolocate flying insects, track them through space, and ultimately eat them. Many nocturnal insects including moths countered with the evolution of sonar detection devices - ears - that alert insects to the echolocation cries of approaching bats. Moths take evasive action in the form of loops, spirals, and power dives and an impressive aerobatic "dog fight" between predator and prey ensues. Tiger moths (Lepidoptera: Arctiidae) have added a new twist to the fray. Tiger moths answer bats with a series of intense ultrasonic clicks produced by paired thoracic structures called tymbals. For over thirty years researchers have attempted to determine why tiger moths answer bats. There are currently three theories about the proximate mechanisms by which the sounds work. First, it is possible that moths produce sounds that startle bats, giving them a momentary advantage in aerial combat. Second, bats may jam the sophisticated ultrasonic echolocation system of bats by sending out sounds that mimic moth echoes but with inappropriate timing. The third possibility is that tiger moths send out an acoustic warning that they are not palatable food items, much as insects use bright colors to warn visual predators that they are noxious. These hypotheses are not considered mutually exclusive and they may all work simultaneously. The proposed experiments will take the three theories to the next level - from the level of proximate questions about mechanism to the level of ultimate questions about the evolution of behavior. Using two novel approaches - a learning approach and a phylogenetic approach - the selective advantages of tymbals will be determined. Laboratory experiments in which bats are pitted against insects with and without chemical defenses or sound will reveal how learning has shaped bat-moth acoustic interactions. Cladistic methods will then be used to explore when, where, and how tymbals originated and why they have been maintained for millions of years since their origin. The answers to these question will not only explain the fascinating details of bat-tiger moth evolution, they will also illustrate how a keystone behavioral innovation has allowed a temporary escape from predation and the radiation of a clade of ~11,000 species in relatively predatory free space. The results of these experiments will be shared with grade school children through a new website dedicated to the interactions of "Bats and Bugs". The information will also be added to an exciting new ecological and environmental curriculum being developed in cooperation with the Archbold Biological Station near Lake Placid, Florida.
