Abstract
Behaviour is a fundamental parameter for understanding the animal fitness, serving as an indicator of exposure to stressors. In ecosystems, animals often face multiple stressors simultaneously. Their behavioural responses may vary when exposed to each stressor individually, as synergistic, additive, or antagonistic effects can result from the interaction of multiple stressors. Therefore, it is imperative to conduct studies that take into account the common occurrence of multi-stress scenarios in aquatic ecosystems. We tested the effects of three sources of stress (low water pH, toxicity (acetone) and conspecific chemical cues) on the behaviour of the aquatic nail Potamopyrgus antipodarum (Tateidae, Mollusca). We evaluated the impact of each stressor, as well as in combinations of two or three stressors simultaneously. The highest time to start movement was shown by the animals of the low water pH (acid treatment-A) followed by A plus toxic treatment (AT). The linear models showed an increase in the cumulative differences in time to start movement for the snails of A, AT, and T treatments over time. This indicates that snails in these treatments took longer to begin sliding movements compared to the control animals. On the contrary, animals of the conspecific chemical cues (S) and ST treatments showed an increased in the time to start sliding with time in comparison with control snails. It is conclude that behaviour was altered depending on the source and combination of stress, with antagonistic effects when simultaneously exposing the animals to an acidic environment and conspecific signals.