Fighting Fish and Biting Wasps

Abstract

ANIMAL COMMUNICATION Animal signaling is usually studied in terms of just two parties—sender and receiver. Doutrelant et al. show that the nature of one-to-one communication can be altered by the presence of an onlooker. Male Siamese fighting fish, Betta splendens , display vigorously to each other, and their displays often are witnessed by other individuals—“eavesdropping” males or females who may glean information about the quality of potential mates or competitors. The displays are unchanged in the presence of an eavesdropping male, but in the presence of females the displays become less overtly aggressive (biting) and more showy (tail beating and prolonged gill cover erection). The effect of an audience might explain why conspicuous signals are ingredients in both intersexual and intrasexual communication, their proportions reflecting a tradeoff between the two functions. Communication with a quite different function is found in social insect colonies, where much of the interaction between individual nestmates concerns benefits to the colony, such as exchange of information and division of labor. O'Donnell documents the curious behavior of the wasp Polybia occidentalis , whereby the workers engage in “social biting.” Biting of one worker by one or more others, sometimes lasting for up to 10 minutes, has the effect of encouraging the bitten to leave the nest on foraging excursions. — AMS Behav. Ecol. 12 , 283; 353 (2001).