ABSTRACT In East Tennessee, the firefly Photuris versicolor quadrifulgens Barber (hereafter referred to as P. quadrifulgens) is one of the first flashing fireflies to appear in spring. It flies over grassy pastures and meadows and into tree branches next to the meadows. This species was studied because it was the first Photuris of the season and it occurred alone, thereby minimizing uncertainty of female identity. Male P. quadrifulgens produce two- to five-pulsed flash patterns: 11% are two-pulsed, 48% are three-pulsed, 37% are four-pulsed, and 3% are five-pulsed. The pulse duration was ca. 0.2 sec (18oC) and was repeated every 0.7 to 0.9 sec so the three- to four-pulse flash patterns lasted 2 to 3 sec. The flash pattern interval averaged 4.5 to 9.0 sec (18oC). Male P. quadrifulgens also produced flicker flashes 0.5 to 1 sec long. The interval for the flicker flashes averaged 3.3 to 5.5 sec (18oC). One courtship flash exchange was observed between male and female that allowed the male to locate and mate with the female within seconds. Twelve female P. quadriflugens were collected and reared to lay their eggs. Ten of the 12 females laid eggs and produced first instars. Six of the 12 females attacked male Photuris in their containers, but they lived together an average of 5.1 days. When other fireflies were added to the containers females readily attacked some, but avoided others. Mated P. quadrifulgens females did not appear to be aggressive mimics because they did not respond to any advertising flashes and seldom responded to simulated firefly flashes. Several functions may operate with P. quadrifulgens flashing. Advertising flashes clearly function in courtship flash communication, but they may also operate as aposematic signals. Periodic flashes and flicker flashes may be aposematic signals for potential predators, but the evidence for this is still limited. Current evidence does not seem to support (nor disprove) the male mimicry hypothesis or the sexual selection hypothesis for P. quadrifulgens, but these hypotheses may work better for other Photuris species.
Keywords: Photuris quadrifulgens, Pyractomena dispersa, flicker flash patterns, aggressive mimicry, male flash mimicry, courtship flash communication, aposematic behaviour