A field cricket's solutions to the cocktail party problem in conspecific choruses

Abstract Many animals signal in choruses to attract mates and reduce predation risk, but simultaneous signaling creates acoustic masking which impairs signal detection and recognition, akin to the cocktail party problem. The severity of interference is likely to be higher in conspecific choruses due to higher signal similarity between signalers, ruling out acoustic niche partitioning as seen in heterospecific choruses. In this study, we examined conspecific masking avoidance in conspecific choruses of a field cricket, Acanthogryllus asiaticus. Field-based measurements revealed that males call from choruses of up to 19 males, with the average nearest neighbor distance between males being 3 m. Transmission experiments showed that the calls of the males transmit up to 3 m and a focal male was likely to have 2 maskers on average, of which one would fall within the hearing distance of the focal male. In absence of any masking avoidance strategies, the average active space overlap, calculated across 10 natural choruses, was found to be 40% and as high as 98%. However, field measurements suggested that focal males actively adjusted call timings to alternate with the audible masker. This was subsequently confirmed in controlled lab playback experiments. Thus, male spacing, limited sound transmission along the ground, and precise adjustment of call timings together reduced average acoustic overlap between maskers to <20% even in loud conspecific choruses. This study highlights how solutions to common problems, such as acoustic masking, vary starkly and behavioral adjustments become crucial when acoustic niche partitioning is ruled out.