Predator‐induced defences under tropicalisation: A biogeographic approach

Abstract Aim The biogeography of predator‐induced defences is an understudied area predator–prey dynamics. Range overlap with predators that induce the response and local demographics (e.g., prey abundances) are likely to be important factors for determining biogeographic distribution induced within species. However, climate warming, range‐expanding warm‐water increasingly preying upon temperate This a consequence wider phenomenon known as tropicalisation. We aim determine: (i) if individuals barnacle (‘bent morphs’) primarily present where they co‐occur (muricid snails) and, (ii) bent morphs size‐structured populations. Location North‐eastern Pacific rocky intertidal zone (~26–40° N). Taxon Tetraclita rubescens (Nilsson‐Cantell, 1931), Balanomorpha. Methods use photoquadrats from sites across range T. determine populations assess size‐structure. combination field surveys, literature, museum occurrences between cool their association abundance patterns . Results Bent commonly found equatorward portion species' (where abundances highest), in overlapping predators. occur smaller size classes. Main conclusions To partly resilient effects tropicalisation, must acclimatise/adapt altered Predator‐induced one way do this. show species ( ) largely restricted large‐bodied evidence partial resilience tropicalisation provides rationale further exploration eco‐evolutionary consequences this study system others.