Social Context Affects Camouflage in a Cryptic Fish Species

Crypsis, or the ability to avoid detection and/or recognition, is an
important and widespread anti-predator strategy across the animal kingdom.
Many animals are able to camouflage themselves by adapting their body
colour to the local environment. In particular, rapid changes in body
colour are often critical to the survival of cryptic prey which rely on
evading detection by predators. This is especially pertinent for animals
subject to spatiotemporal variability in their environment, as they must
adapt to acute changes in their visual surroundings. However, which
features of the local environment are most relevant is not well
understood. In particular, little is known about how social context
interacts with other environmental stimuli to influence crypsis. Here we
use a common cryptic prey animal, the goby (Pseudogobius species 2) to
examine how the presence and body colour of conspecifics influences the
rate and extent to which gobies change colour. We find that solitary
gobies change colour to match their background faster and to a greater
extent than gobies in pairs. Further, we find that this relationship holds
irrespective of the colour of nearby conspecifics. This study demonstrates
the importance of social context in mediating colour change in cryptic
animals.