Differential investment in acoustic communication during social interactions in two closely-related sand goby species

Communication signals provide key information for conspecific recognition, mate choice and rival assessment. The painted goby Pomatoschistus pictus and the common goby P. microps are two closely-related sand goby species, often sympatric and with an overlapping breeding season. In this study we staged male–male and male–female interactions and compared visual, tactile and acoustic behaviour in both species. Sound production in the common goby is here accounted for the first time. We observed some differences in visual behaviour and a striking divergence in the use of tactile and acoustic communication during courtship and agonistic interactions. We further describe differences in drumming signals with social context in the painted goby. This study suggests a divergence in communication in two closely-related sand goby species and emphasizes the importance of further research concerning the role of multimodal communication in closely-related species.