Female preference for male courtship flashes in Photinus ignitus fireflies

Abstract

In Photinus fireflies, males produce spontaneous bioluminescent courtship flashes. Females preferentially respond to particular male flashes with flashes of their own. This study explored variation in female flash responsiveness as a function of male flash duration, female condition, lantern size, and lantern distance, as well as the relationship between male characteristics and spermatophore mass in Photinus ignitus fireflies. We determined female preference by scoring female flash response to simulated male flashes and determined variation in overall female flash responsiveness for laboratory-mated, laboratory-fed, and control P. ignitus females. Flash duration, lantern size, and body mass were recorded for field-collected males. Males were then mated to determine spermatophore mass. Females exhibited greater preference for artificial flashes representing the upper range of conspecific male flash duration and lantern size as well as flashes produced at a closer distance. Both laboratory-mated and laboratory-fed P. ignitus females showed lower overall responsiveness across all flash durations relative to control females that did not mate or feed in the laboratory. Male flash duration predicted a significant proportion of the variation in spermatophore mass for early-season males. These results suggest that female Photinus ignitus may prefer long flashes in order to obtain the direct benefit of larger spermatophores and may adjust their overall flash responsiveness as the relative importance of this benefit varieswith changing female condition. Copyright 2003.