Does predation pressure alter the visual properties of prey? An assessment of the guppy Poecilia reticulata

Abstract

Evolution of male-biased coloration in the guppy Poecilia reticulata is driven by sexual and natural selection. The colorful male ornaments are attractive to females, but also attract predators. Distinct predation regimes in Trinidadian streams promote the evolution of different guppy color morphs, with male ornamentation and female mate preference also co-evolving among populations. How attractive a male guppy color morph is to a female depends not only on the coloration itself, but also on how strongly the morph evokes stimulation of the female visual system. Both allele type and gene expression levels of cone opsin genes play a role in female mate preferences. Previous studies have demonstrated that predation can alter female guppy mate choice, but the underlying mechanism remains unclear. Here, I hypothesize that guppies adjust their cone opsin expression profiles in response to predation pressure. Although I detected a significant change in LWS-R transcription in response to predation, cone opsin expression profiles in adult female guppies do not appear to be driven by predation pressure. However, the impacts of predation pressure on developmental plasticity in cone opsin expression and brain anatomy remain promising avenues of further investigation to determine how predators affect female mate preference in guppies.