Behaviour 2019
Evidence of Social Influences on Learning in Embryonic Minnows
Brooke Karasch, Jessica Ward. Ball State University, Muncie, IN, United States

Potential influences of the embryonic social environment on learning and behavior in oviparous aquatic organisms have been largely unexplored. However, the proximity of eggs in a clutch may present opportunities for social transmission of information. We assessed whether two clutch attributes, group size and embryo arrangement, influence predator recognition and antipredator behavior in fathead minnow embryos (Pimephales promelas). We collected embryos on the day they were laid and assigned them to groups of 1, 2-5, or 10-15 eggs. Half were clustered (in physical contact) and the other half were dispersed (no contact). Eggs were kept for 5 days in control water, or conditioned each day with olfactory cue from a piscivorous predator, bluegill sunfish (Lepomis macrochirus), and conspecific alarm cue. We evaluated embryonic activity in the presence of predator cue alone on days 3-5 of development. Embryos showed evidence of learned predator recognition as early as day 3, with clustered embryos and larger groups showing enhanced antipredator response. These findings suggest that social conditions may influence embryonic learning and antipredator behavior in aquatic vertebrate species.