Animal warning signals: a perspective from visual neurosciences

Olivier penacchio

Computer Science Department, Universitat Autònoma de Barcelona, Barcelona, Spain

School of Psychology and Neuroscience, University of St Andrews, St Andrews, Fife, UK

op5@st-andrews.ac.uk

Link to seminar: https://umontpellier-fr.zoom.us/webinar/register/WN_OCtk52LnRWCtkcik06MM7Q

Aposematic prey warn potential predators that they are unpleasant or unprofitable to eat using striking colour patterns. Despite their diversity, the patterns involved in these warning signals seem to share some common visual characteristics, such as the inclusion of yellow and red, the presence of repetitive elements, or high internal contrast. However, while aposematism has been a key testbed for evolutionary theory for over a century, an objective quantification of the common features of effective warning signals is still missing.

Here, I will propose a principled characterisation of warning signals based on their impact on the visual system of the receiver. Using the predator–prey system of birds foraging on lepidopteran prey, along with modelled avian visual systems, I will demonstrate that warning signals elicit significantly stronger activity in model visual systems compared to the patterns of undefended species. This heightened activity also enables them stand out against natural backgrounds. Conversely, evolving colourations in silico to trigger strong neural activity in a model of the avian brain produces patterns reminiscent of warning signals. I will then discuss how this objective and quantitative definition of warning signals offers a novel contribution to the literature on sensory drive, sensory exploitation, and receiver psychology, thereby opening new perspectives for understanding and testing the evolution of warning signals, and, more generally, how sensory systems constrain signal design.

Watch previous seminars on our YouTube channel: https://www.youtube.com/channel/UCrX4IsZ8WIFcDa0ZmC7rcQg