CASE, J.F.; Univ. of California, Santa Barbara: Lessons learned from flying fireflies on a stick

Mating localization in many fireflies requires a flying male. To perform sufficiently detailed studies of this behavior a wind tunnel was equipped to record and respond to the luminous and flight orientation behavior of a male or female Photinus pyralis flying on a recording pivot. The apparatus records direction and other flight parameters, provides high magnification strobed IR video, and automatically generates LED interrogations or responses. Males exhibit normal patrol flight behavior and reveal new details of how the flying male orients to the perched female, what determines choice of a respondent, and how persistent is his courtship flight vector to multiple respondents and improperly timed or absent responses. Females, rare flyers in nature, fly vigorously in the apparatus, responding to LED flashes in two ways. An early response is analogously timed to the male-male in-flight interaction flash and occurs only in flight. A later response corresponds to the normal reply of the perched female to the male. Buck and Case venture that the early response represents a genderally common expression of an evolutionarily early communication mode. The male and female would have responded to each other at the minimum possible eye-light organ transmission delay, perhaps a derivative of a primitive alarm response. The apparatus provides information on how the perched female copes with the problem of maximizing visual sensitivity in the presence of optical noise. Earlier work by Buck and Case on Photinus greeni and the Malaysian synchronizer, Petroptyx tener, supports these observations, as do studies on the midwater luminescent shrimp Gnathophausia.