How the moth got its ears and other just-so stories in the history of bat–moth interactions

Evolutionary biology is replete with adaptive origin stories for traits. Many such hypotheses, however, are untestable and do not include alternative explanations or nonadaptive thinking. The study of bat–moth interactions is no exception. Most antibat traits in moths are proposed to have originated from the selective force of echolocating bats. However, bat–moth researchers often do not distinguish current utility from reasons for origin, even in the face of evidence for co-option and by-product origins in other systems. Ultimate evolutionary questions are among the hardest to ask and answer, requiring the effort of entire scientific communities to amass the proximate behavioral and physiological understanding necessary to propose and test robust hypotheses. We address several just-so origin stories in bat–moth interactions including ultrasound-sensitive ears, defensive sound production, stealth sonar, ultrasound-absorbing scales, and acoustic diversion and propose what evidence is required to determine if bat–moth battles drove the origination of these traits.