Together We Stand – Analyzing Schooling Behavior in Naive Newborn Guppies through Biorobotic Predators

A major advantage of animal aggregations concerns cooperative antipredator strategies. Schooling behavior emerges earlier in many fish species, especially in those cannibalizing their offspring. Experience is fundamental for developing schooling behavior. However, the cognitive ability of naive newborn fish to aggregate remains unclear. Herein, Poecilia reticulata, was selected as model organism to investigate how combinations of biomimetic robotic agents and adult conspecific olfactory cues affect collective responses in newborns. The role of white and brown backgrounds in evoking aggregations was also assessed. Olfactory cues were sufficient for triggering aggregations in P. reticulata newborns, although robotic agents had a higher influence on the group coalescence. The combination of robotic agents and olfactory cues increased schooling behavior duration. Notably, schooling was longer in the escape compartment when robotic agents were presented, except for the combination of the male-mimicking robotic fish plus adult guppy olfactory cues, with longer schooling behavior in the exploring compartment. Regardless of the tested cues, newborn fish aggregated preferentially on the brown areas of the arena. Overall, this research provides novel insights on the early collective cognitive ability of newborn fish, paving the way to the use of biomimetic robots in behavioral ecology experiments, as substitutes for real predators.