Divergent alternative mating tactics in convergent male reproductive morphs.

Alternative reproductive phenotypes involve polymorphic behaviors and forms within sexes. Testing whether behavioral variants such as alternative tactics (eg sneaking or satellite behavior) are initially co-expressed or decoupled from morphological polymorphisms (eg weapon size or color pattern) can provide insight into the origins of reproductive diversity. In Hawaiian field crickets (Teleogryllus oceanicus), an eavesdropping parasitoid fly selected for rapid, parallel evolution of male wing mutations that reduce acoustic signals. Two of these, "flatwing" and "curly-wing", co-occur in populations alongside ancestral "normal-wing" males that can sing. These convergent alternative morphs may both rely on satellite tactics in which nonsinging males position themselves near calling males to intercept females, rather than attracting mates directly by producing a conspicuous song. Here, we test whether flatwing and curly-wing vary in their tendencies to express satellite behavior using playback experiments with virgin, unmanipulated males simulating natural conditions. Surprisingly, flatwing males were significantly less likely to behave as satellites than normal-wing or curly-wing males. Normal-wing males with poorer body condition were more likely to behave as satellites, consistent with theory and previous findings, but the reduced-sound morphs showed no such condition dependence. Our findings suggest that morph-specific variation in the tendency to adopt satellite behavior may contribute to the maintenance of convergent male reproductive morphs; future work would benefit from testing whether such variation is driven by acoustic self-assessment. A decoupled relationship between behavioral reproductive tactics and morphological reproductive strategies may promote diversification of alternative mating morphs in nature.