BS in Biological Sciences
Biological Sciences Department
Guppies, Poecilia reticulata, are a model species for studies of female preference based on male courtship displays; however, males also display to each other in an aggressive context, and little attention has been paid to the role of male-male displays. The display involves a male positioning his body in front or to the side of another male, arching his body, and quivering with his dorsal fin splayed. To understand what behaviors elicit a male display, we assigned individual males a dominance status. We then examined the relationship between dominance status and the number of displays delivered and received. By knowing the status of a displaying individual, we can better understand whether the display is given more often by dominant or subordinate individuals. Our results showed no significant correlation between dominance status and display rate; however, we found a significant relationship between the number of displays received and the number of displays delivered. Additionally, we found that a display is most often followed by aggression (nips and chases) by the other male rather than aggression by the focal male. Our results suggest that the display is a subtle form of aggression that escalates agonistic interactions. It also may serve to convey information about male quality (e.g. by displaying color patterns) and aggressive intent.