VARIATION IN THE FLASH PATTERN OF THE FIREFLY, PHOTURIS VERSICOLOR QUADRIFULGENS (COLEOPTERA, LAMPYRIDAE)

We sampled a population of signaling Photuris versicolor quadrifulgens fireflies to quantify the variation in flash patterns emitted by male s. Males produced five distinct flash patterns during their mate-searc hing flights. Four of the patterns consisted of two to five equal-inte nsity pulses and the fifth pattern type was a Picker, a group of rapid modulations in intensity. We found that the proportions of each patte rn remained relatively constant from night to night throughout the sea son. The different flash patterns produced varied significantly with t ime of night; patterns having fewer pulses occurred earlier in the eve ning. Local density, an estimate of competition, did not significantly correlate with flash pattern type. On consecutive emissions, individu als changed their flash types with a mean probability of 0.12 (over al l males), and they usually switched between patterns differing by a si ngle pulse (from a two- to a three-pulse pattern, from a three- to a t wo-pulse pattern, etc.). The nightly temporal changes in flash pattern s may be related to tradeoffs between female availability and energeti c costs of signaling or the changes may be related to increased predat ion risk from visual predators.