Several Nymphalidae butterflies possess a sensory structure called the Vogel’s organ (VO) that is proposed to function in hearing. However, little is known about the VO’s structure, taxonomic distribution or function. My first research objective was to examine VO morphology and its accessory structures across taxa. Criteria were established to categorize development levels of butterfly VOs and tholi. I observed that enlarged forewing veins are associated with the VOs of several species within two subfamilies of Nymphalidae. Further, I discovered a putative light/temperature-sensitive organ
associated with the VOs of several Biblidinae species. The second objective was to test the hypothesis that insect ears function to detect bird flight sounds for predator avoidance. Neurophysiological recordings collected from moth ears show a clear response to flight sounds and chirps from a live bird in the laboratory. Finally, a portable electrophysiology rig was developed to further test this hypothesis in future field studies.