  Large-scale ecotoxicological studies have technical and ethical limitations,
both related to the need to expose individuals to potentially harmful
compounds. Computational modeling is a complementary useful and predictive tool
that overcomes these limitations. Considering the increasing interest in the
effects of pesticides on behavioral traits, the aim of this study was to
evaluate the effects of chlorpyrifos (CPF) on intra- and inter-specific
interactions of anuran tadpoles, complementing traditional ecotoxicological
tools with a theoretical analysis verified by computational simulations.
Experiments were developed under two consecutive phases: a first phase of
exposure, and a second phase of interactions. The second phase consisted of
evaluating the effects of CPF on intra- and inter-specific interactions of
exposed C. ornata (Co) tadpoles acting as predators and unexposed Rhinella
fernandezae (Rf) tadpoles acting as prey, under different predator-prey
proportions. Also, intraspecific interactions of three Co tadpoles under
different conditions of exposure were evaluated. During the exposure phase,
chlorpyrifos induced significant mortality from 48h, irregular swimming, tail
flexure, and the presence of subcutaneous air. Also, it induced effects on the
sounds emitted after 96h of exposure, registering less number of pulses and
higher dominant frequencies, and altered intra- and inter-specific
interactions. During the interaction phase, the larvae continued to show sound
effects, however, the antipredator mechanism continued to be operating and
efficient. Finally, it was possible to model the behavior of the larvae under
the effects of chlorpyrifos. We conclude that experimental data and
computational modeling matched within errors. Therefore, computational
simulation is a valuable ecotoxicological tool that provides new information
and allows predicting natural processes.
