Context-dependent multimodal behaviour in a coral reef fish: Stage 1 & 2 total duration and count data in behaviour trials

Animals are expected to respond flexibly to changing circumstances, with
multimodal signalling providing potential plasticity in social
interactions. Whilst numerous studies have documented context-dependent
behavioural trade-offs in terrestrial species, far less work has
considered such decision-making in fish, especially in natural conditions.
Coral reef ecosystems host 25% of all known marine species, making them
hotbeds of competition and predation. We conducted experiments with wild
Ambon damselfish (Pomacentrus amboinensis) to investigate
context-dependent responses to a conspecific intruder; specifically, how
nest defence is influenced by an elevated predation risk. We found that
nest-defending male Ambon damselfish responded aggressively to a
conspecific intruder, spending less time sheltering and more time
interacting, as well as signalling both visually and acoustically. In the
presence of a model predator compared to a model herbivore, males spent
less time interacting with the intruder, with a tendency towards reduced
investment in visual displays compensated for by an increase in acoustic
signalling instead. We therefore provide ecologically valid evidence that
the context experienced by an individual can affect its behavioural
responses and multimodal displays towards conspecific threats.