Flash signals, nuptial gifts and female preference in photinus fireflies

The evolution of male courtship signals such as the bioluminescentflashes of fireflies may be shaped, at least in part, by femalepreference for particular characteristics of the male signal.These female preferences for male courtship signals may ariseas a result of the benefits of choosing males with particulartraits. One possible benefit of mate choice occurs if femalescan use male courtship signals as an honest indicator of malenutritional contributions at mating, nuptial gifts. This paperreviews female preference for male flash characteristics inPhotinus fireflies (Coleoptera: Lampyridae), and the potentialfor females to use male flash characteristics to predict nuptialgift quality. In Photinus firefly species with single pulseflashes females preferentially respond to flashes of greaterintensity and duration. Male Photinus provide a nuptial giftto females at mating in the form of a spermatophore and flashduration serves as a good predictor of spermatophore mass formales collected early in the season. However, Photinus firefliesdo not feed as adults, so spermatophore mass decreases withsubsequent matings. In response, nutrient-limited females maystop preferentially responding to longer duration flashes, increasingtheir overall responsiveness later in the mating season as theyforage for spermatophores. Therefore, the evolution of malecourtship signals in Photinus fireflies is the product not onlyof female preference for male flash characteristics, but alsothe costs and benefits of female choice that shape these preferences.