Meeting Abstract

 

P1-173  Friday, Jan. 4 15:30 – 17:30  The effect of salinity on heterospecific and conspecific aggression in two closely related guppy species, Poecilia reticulata and Poecilia picta. BOCKRATH, RE*; MARSHALL, CA; GHALAMBOR, CK; Colorado State University; Colorado State University; Colorado State University rachbock@rams.colostate.edu

Behavioral dominance in the form of heterospecific and conspecific aggression between species is thought to be an important ecological process shaping the abundance and distribution of organisms, but few studies have examined how such interactions change across different contexts. Poecilia reticulata and Poecilia picta are closely related fish species that can tolerate a wide range of salinities, but on the island of Trinidad, P. reticulata is confined to freshwater habitats whereas P. picta is found in freshwater and brackish water. Here we investigated whether changes in behavioral dominance (measured as aggression) could explain why P. reticulata is excluded from brackish water. Levels of aggression were compared within species across two different salinities – their home salinity where they are kept, and the away salinity of 15 ppt. We find no evidence that P. picta is behaviorally dominant to P. reticulata in brackish water. Instead we observed significant individual level variation, where some individuals were consistently aggressive across different salinities independent of whether they were interacting with hetero- or conspecifics. Such results suggest individual personalities play a bigger role in aggressive interactions compared to species differences.