Meeting Abstract

46.1  Wednesday, Jan. 5  Preferences for color and pattern may explain reproductive isolation in sympatric darter species WILLIAMS, TH*; MENDELSON, TC; University of Maryland, Baltimore County; University of Maryland, Baltimore County tory1@umbc.edu

Numerous closely-related animal species can be distinguished based on differences in ornate coloration or patterning. These elaborate color patterns are thought to play a role in mate choice within populations and to pose a barrier to interbreeding between species, with individuals preferring the color patterns of conspecifics. However, the role of color or pattern in maintaining species boundaries between closely related taxa is rarely tested explicitly. The present study tests whether individuals in a pair of sympatric species prefer conspecific mates based on species-specific color and pattern. “Darters” are a diverse group of North American freshwater fish well known for striking nuptial color patterns exhibited by the males of many species. Previously, we showed that the sympatric darter species Etheostoma barrenense and E. zonale are behaviorally isolated and they appear to prefer conspecific males based on visual cues alone. Here, we utilized dummy fish to isolate and mimic components of male phenotypes to test whether female E. barrenense and E. zonale prefer conspecific males based specifically on color or pattern. We demonstrate through three treatments of dichotomous choice trials that females of both species prefer both conspecific color and pattern elements over those of the heterospecific. This study is the first to provide evidence that darters may distinguish between colors and patterns, and, to our knowledge, the first to combine color manipulation with carefully controlled behavior to conclusively demonstrate a preference for conspecific color per se.