University of Veterinary Medicine Vienna The evolution and ecology of multiple antipredator defences Prey seldom rely on a single type of antipredator defence, often using multiple defences to avoid predation. In many cases, selection in different contexts may favour the evolution of multiple defences in a prey. However, a prey may use multiple defences to protect itself during a single predator encounter. Such "defence portfolios" that defend prey against a single instance of predation are distributed across and within successive stages of the predation sequence (encounter, detection, identification, approach (attack), subjugation and consumption). We contend that at present, our understanding of defence portfolio evolution is incomplete, and seen from the fragmentary perspective of specific sensory systems (e.g., visual) or specific types of defences (especially aposematism). In this review, we aim to build a comprehensive framework for conceptualizing the evolution of multiple prey defences, beginning with hypotheses for the evolution of multiple defences in general, and defence portfolios in particular. We then examine idealized models of resource trade-offs and functional interactions between traits, along with evidence supporting them. We find that defence portfolios are constrained by resource allocation to other aspects of life history, as well as functional incompatibilities between different defences. We also find that selection is likely to favour combinations of defences that have synergistic effects on predator behaviour and prey survival. Next, we examine specific aspects of prey ecology, genetics and development, and predator cognition that modify the predictions of current hypotheses or introduce competing hypotheses. We outline schema for gathering data on the distribution of prey defences across species and geography, determining how multiple defences are produced, and testing the proximate mechanisms by which multiple prey defences impact predator behaviour. Adopting these approaches will strengthen our understanding of multiple defensive strategies. en TEXT review Genetic Trade-Off; Warning Signals; Multisensory Integration; Predator Avoidance; Chemical Defenses; Body-Size; Color; Aposematism; Prey; Costs 2023 2023 Kikuchi, David W. (Oregon State University / Bielefeld University) Exnerová, Alice (Charles University) Smart, Hannah R. (Western Sydney University) Skelhorn, John (Newcastle University) Sherratt, Thomas N. (Carleton University) Schaal, Kaitlin A. (ETH Zurich) Roy, Arlety (University of French Guiana) Rowland, Hannah M. (Max Planck Institute for Chemical Ecology) Rowe, Candy (Newcastle University) Rößler, Daniela C. (University of Konstanz / Max Planck Institute of Animal Behavior) Rönkä, Katja H. (University of Helsinki) Rojas, Bibiana (University of Veterinary Medicine Vienna / University of Jyväskylä) Yeager, Justin (Universidad de las Américas) Reader, Tom (University of Nottingham) Raška, Jan (Charles University) Penacchio, Olivier (University of St Andrews / Universitat Autònoma de Barcelona) Pekár, Stano (Masaryk University) Pal, Arka (Tata Institute of Fundamental Research) Páez, Erika (Université des Antilles) Nawge, Viraj (Tata Institute of Fundamental Research) Medina, Iliana (University of Melbourne) McLellan, Callum F. (University of Bristol) McClure, Melanie (University of French Guiana) Winters, Anne E. (University of Exeter) Lorioux-Chevalier, Ugo (University of French Guiana) Lindstedt, Carita (University of Helsinki) Leavell, Brian C. (Purdue University) Kunte, Krushnamegh (Tata Institute of Fundamental Research) Joron, Mathieu (Université de Montpellier) Hossie, Thomas J. (Trent University) Herberstein, Marie E. (Macquarie University) Hämäläinen, Liisa (Macquarie University) Elias, Marianne (Université des Antilles / Smithsonian Tropical Research Institute) Daňková, Klára (Charles University) Umbers, Kate (Western Sydney University) Cheney, Karen L. (University of Queensland) Burdfield-Steel, Emily R. (University of Amsterdam) Allen, William L. (Swansea University) Arbuckle, Kevin (Swansea University) Aubier, Thomas G. (University of North Carolina at Chapel Hill / Université Toulouse III - Paul Sabatier) Briolat, Emmanuelle S. (University of Exeter) Thorogood, Rose (University of Helsinki) Taylor, Christopher H. (University of Nottingham) Summers, Kyle (East Carolina University) Stefan, Amanda M. (Carleton University) Stankowich, Ted (California State University, Long Beach) Wiley