Meeting Abstract

P2-57    You Only Like Me With the Lights Out: Effects of Light on Guppy Mating Behavior Grant, E*; Yang, Y; Seymoure, B; Gordon, S; Washington University in St. Louis; Washington University in St. Louis; Washington University in St. Louis; Washington University in St. Louis ellygrant97@gmail.com

Light is a significant influencer of animal behavior, and it naturally varies across space and time. Trinidadian guppies (Poecilia reticulata) rely largely on visual cues to find food, signal mates, and avoid predators. Under bright lights colorful male guppies are most attractive to potential mates, but are also most obvious to predators, especially during showy courtship displays. Previous research suggests that male guppies often reduce their activity under brighter light, instead focusing their mating efforts in dimmer light conditions and harassing females with sneak mating attempts instead of courtship displays when predators may be present. This increased male harassment may create sexual conflict as females must choose between foraging at peak hours and dodging unwanted mating attempts. Here we investigate the ecological effect of natural light on foraging and mating behaviors in F2 guppies from high-predation (HP) and low-predation (LP) lines. We introduced groups of HP and LP guppies into semi-natural stream mesocosms, and collected data on male mating and female foraging behaviors at dawn, midday, and dusk. We quantified natural light for each mesocosm with a spectrometer at time of observations. Results showed that guppies were more active in dimmer light regardless of predation regime. HP males performed more sneak matings, especially at dusk, while LP males were less active compared to HP males and opted for courtship displays over sneak mating. HP females foraged less frequently compared to LP females, perhaps due to the higher levels of male harassment. Here we show that variation in light can be a strong driver of spatial and temporal patterns of sexual and foraging behaviors, consequently influencing the evolution of sexually selected traits and the ecological impact of animals on the environment.