Single versus multiple cues in mate discrimination by males and females

Courtship communication can function in both species recognition and mate choice. Little is known about how animals prioritize signals or cues for species identification versus intraspecific mate choice when several information sources are available, such as when communication spans several sensory modalities or spatiotemporal scales. Cricket courtship, for example, involves transmission of acoustic signals as well as chemosensory contact. We explored how chemical cues function in sex and species recognition for both male and female crickets, and then evaluated their use in a mating context where additional stimuli were available. First, we observed the response of female and male Gryllus integer to the chemical cues of conspecifics and sympatric G. lineaticeps. Males' strongest response was to conspecific female chemical cues. Although females responded most strongly to male chemical cues, they did not show species discrimination. Next, we compared the responses of male and female G. integer to conspecifics and heterospecifics in mating trials. Females directed more aggressive behaviour and less chemosensory behaviour towards heterospecific males, but males courted females of both species with equal intensities. These results suggest a sex-based difference in cue usage: for males, the additional stimuli present during mating trials appeared to override species-specific chemical cues, whereas for females, additional stimuli apparently bias responses towards conspecifics.