HUMFELD, S.C.: Satellite male green treefrogs are competitively inferior

Individuals of different competitive abilities or in certain environmental circumstances adopt different alternative mating tactics as a conditional strategy. Male green treefrogs (Hyla cinerea) primarily produce acoustic signals to attract females; however, satellite males do not produce advertisement calls and attempt to intercept and mate with females attracted to another calling male. Satellite males are not incapable of calling; they may switch tactics within and between nights. In an observational field study, I recorded advertisement calls and body measurements of males adopting calling and satellite mating tactics as a preliminary investigation of the intrinsic and extrinsic factors that lead males to adopt alternative mating tactics. Satellite males were significantly smaller, less weighty and in poorer condition than calling males (P < 0.04). Repeated measures analysis of frogs observed using both tactics indicates the existence of size-independent mating tactic choice based on condition; seven of eight males observed using both tactics were in poorer condition as satellites (P < 0.03). Satellite males produced higher frequency advertisement calls than callers (P < 0.02), which are less attractive to females choosing mates. When the effects of mass on frequency are statistically removed, satellite males still produce higher frequency calls. A significant negative correlation (r = -0.30, P < 0.05) between condition and call frequency within the population suggests that poor condition may constrain males to produce unattractive, high-frequency advertisement calls. I conclude that males adopting the satellite mating tactic are at a competitive disadvantage for obtaining mates using the calling tactic and may maximize their opportunities for mating by parasitizing males more likely to attract females.