Meeting Abstract

 

141-2  Monday, Jan. 7 13:45 – 14:00  The cascading effects of aggression on trophic innovation and reproductive isolation within an adaptive radiation of pupfishes ST. JOHN, ME*; MARTIN, CH; Univ. of North Carolina, Chapel Hill; Univ. of North Carolina, Chapel Hill Michelle.e.stjohn@gmail.com

Behavioral changes in a new environment are often assumed to precede the origins of evolutionary novelties. Here, we examined whether an increase in aggression is associated with a novel scale-eating trophic niche within a recent radiation of Cyprinodon pupfishes endemic to San Salvador Island, Bahamas. We measured aggression using multiple behavioral assays and used transcriptomic analyses to identify candidate gene pathways underlying aggression across three sympatric species in the San Salvador radiation (generalist, snail-eating specialist, and scale-eating specialist) and two generalist outgroups. Surprisingly, we found increased behavioral aggression and differential expression of aggression-related pathways in both the scale-eating and snail-eating specialists. Our results indicate that aggression is not unique to scale-eating specialists. Instead, selection may increase aggression in other contexts such as niche specialization in general or mate competition. Alternatively, increased aggression may result from indirect selection on jaw size, pigmentation, or metabolism—all traits which are highly divergent in this system, exhibit signs of selective sweeps, and may have pleiotropic effects on aggression. Additionally, we discuss whether androgen levels vary across pupfish species, and how varying levels of aggression affect mate preference and feeding behavior.