Variation in the behaviour of an obligate corallivore is influenced by resource availability

Marine environments are subject to increasing disturbance events, and coral reef ecosystems are particularly vulnerable. During periods of environmental change, organisms respond initially through rapid behavioural modifcations. Whilst mean population level modifcations to behaviour are well documented, how these shifts vary between individuals, and the relative trade-ofs that are induced, are unknown. We test whether the frequency and time invested in diferent behaviours varies both between and within individuals with varying resource availability. To do this, we quantify diferences in four key behavioural categories (aggression, exploration, feeding and sociability) at two sites of diferent resource availability, using an obligate corallivore butterfyfsh species (Chaetodon lunulatus). Individuals on a low resource site held larger territories, investing more time in exploration, which was traded of with less time invested on aggression, feeding and sociability. Repeatability measures indicated that behavioural diferences between sites could plausibly be driven by both plasticity of behavior within individuals and habitat patchiness within feeding territories. By combining population-level means, co-correlation of diferent behaviours and individual-level analyses, we reveal potential mechanisms behind behavioural variation in C. lunulatus due to diferences in resource availability.