"Effect of density and predation on behavioural response of anuran larvae

GÓMEZ, VALERIA I.

Minas Gerais

Congreso; XXXVIII Encuentro Anual de Etología, III Reunión de Biología del Comportamiento del Cono Sur; 2021

SBEt - UFJF

The risk of predation can affect the behavior of organisms, and in turn the number of conspecifics can influence the perception of predation risk, affecting the behavior the individuals. Therefore, large groups of individuals are expected to exhibit ?riskier? behavior in contrast to a single individual or a small group because they perceive a lower risk of predation. I performed a series of experiments to examine how odor of a predatory fish (Moenkhausia dichroura) influences the activity of tadpoles of the frogs Physalaemus albonotatus, Rhinella diptycha and Scinax nasicus. The experimental design consisted of two tadpole densities (4 and 8 tadpoles). The activity of tadpoles was observed in four different occasions (treatments): (1) before adding chemical cues of predators, and then at (2) 15 min, (3) 30 min and (4) 45 min after introducing the chemical cues. In each treatment, the behaviour was recorded 5 times (replicates; 5 s each) in each recipient. A repeated measures ANOVA was performed to compare larval activity among the four different occasions. I found that 1) tadpoles of S. nasicus and P. albonotatus were more active at high densities, 2) tadpoles of S. nasicus decreased the activity in the presence of predator odor, 3) tadpoles of R. diptycha increased the activity in the presence of predator odor, 4) activity of the tadpole of P. albonotatus did not differ in the presence or absence of predator odor. These results indicate that there are behavioral differences among anuran species in the ways in which their larvae respond to the presence of predator odor and the number of conspecifics present.