Behavioral flexibility as an adaptation to climatic and anthropogenic stress in an era of global warmingBiology & Ecophysiology

Laurent Seuront¹

¹ CNRS, Laboratory of Oceanology and Geoscience, UMR 8187 LOG, Station Marine Wimereux, France

All animals constantly face the challenge of finding food and mates, while avoiding predators in spatially structured, complex environments. A few theoretical studies have predicted the emergence of fractal patterns and associated power-law distributions to specific optimisation processes. This is consistent with theoretical works suggesting fractal Lévy walks as an adaptive behavioural response to foraging in highly unpredictable and resource-poor environments. However, the potential phenomenological link between habitat properties and animal behaviour remains an open issue in the context of optimal foraging, in particular in intertidal ecology. Most moving intertidal organisms exhibit a vast behavioural repertoire: (i) they do not move following straight lines, but along pathways that can be more or less convoluted, (ii) they alternate periods of activity with periods of relative stasis, (iii) when they move their speed often fluctuates erratically, which is incompatible with a description based on mean speed, and (iv) they exhibit a range of taxes that contribute to their navigation in various landscapes. Understanding the nature of movement is critical in an era of global change characterised by the increase in the frequency, duration and intensity of extreme events such as heatwaves and coldsnaps and the ever-growing impact of anthropogenic stressors. In particular, we are still critially lacking information about the interplay between climatic and anthropogenic stressors in intertidal animal movement behaviour, hence their overall resilience to perturbations. In this context, based on the movement behaviour of a range of key intertidal organisms (e.g. gastropods, mussels and limpets) from various climatic regimes (i.e. France, Portugal, Japan, Hong Kong, South Africa and Australia) observed both in situ and ex situ under laboratory-controlled conditions, the present work describes how the explicit consideration of both the geometric and stochastic components of movements can be used to quantify response strength across stimuli and species. This will be illustrated using examples based on the behavioural response to a range of both naturally occurring chemical cues and a range of anthropogenic contaminants such as plastic leachates, hydrocarbon, caffein and antidepressant.