Meeting Abstract

P3.18  Sunday, Jan. 6  Dear Enemies and Nasty Neighbors in the Crayfish Procambarus clarkii WHITE, M.; ANDREWS, K.*; TIERNEY, A.J.; Colgate University; Colgate University; Colgate University atierney@colgate.edu

The dear enemy effect predicts that territorial animals will respond less aggressively to neighbors compared to strangers. In contrast, there is also a proposed nasty neighbor effect in which familiar conspecifics pose a greater threat than strangers and are hence treated more aggressively. The dear enemy effect has recently been reported in crayfish and used as a measure of individual recognition. Our experiment explored if the crayfish Procambarus clarkii demonstrates dear enemy or nasty neighbor effects, and the role of social status and sex in either behavior. Pairs of size and sex matched crayfish fought to establish social status and the resulting dominant and subordinate crayfish then participated in a choice phase in which they interacted with two conspecifics tethered in an arena. Both choice conspecifics had the same social status and sex, but one was familiar (the focal animal’s previous opponent) and the other was novel. We found that subordinate focal animals of both sexes spent significantly more time in proximity to the unfamiliar choice animal, behavior inconsistent with the dear enemy and nasty neighbor hypotheses. In contrast, male and female dominant focals differed significantly: females spent more time close to and fighting with the familiar choice animal while male dominants responded equivalently to the two choice animals. Thus the response of crayfish toward familiar and unfamiliar conspecifics was complex and not explained by a single hypothesis. We suggest that, in addition to familiarity and unfamiliarity, the perceived threat-level of opponents influences the behavior of crayfish toward conspecifics.