predator-induced defences under tropicalisation: a biogeographic approach

Aim: The biogeography of predator-induced defences is an understudied area of 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 the biogeographic distribution of induced defences within species. However, with climate warming, range expanding warm-water predators are increasingly preying upon temperate species. This is a consequence of a wider phenomenon known as tropicalisation. We aim to determine: (i) if individuals of a temperate barnacle with induced defences (“bent morphs”) are primarily present where they co-occur with range-expanding warm-water predators (muricid snails) and, (ii) if bent morphs are size-structured within populations.
Location: North-eastern Pacific rocky intertidal zone (~26-40ºN)
Taxon: Tetraclita rubescens (Nilsson-Cantell, 1931), Balanomorpha
Methods: We use photo quadrats from sites across the range of T. rubescens to determine the bi...