Octopus body language: body patterns of Abdopus capricornicus during social interactions
摘要
Octopus are well known for their rapidly changing and diverse body patterning achieved through combinations of chromatic, textural, postural and locomotory components. The function of octopus body patterns includes camouflage for prey ambush and predator avoidance, aposematic display to startle intruders and predators, and potentially intraspecific communication. However, as many octopus species are often solitary, body patterning during intraspecific social interactions is largely unexplored. Here we provide the first detailed description of body patterns and the associated components expressed during social interactions of the diurnal reef-dwelling species, Abdopus capricornicus. This is the first study aimed at disentangling the body patterns used for camouflage from those used for communication. This was achieved by staging interactions between octopus pairs under controlled conditions in a bare sand environment devoid of rocks or algae. While most studies on octopus interactions focused on mating behaviour, this study focused on the body patterns expressed during intrasexual (e.g. male-male, female-female) and intersexual interactions. Notably, A. capricornicus shows the richest body patterning repertoire among coastal octopuses studied so far, including 10 body patterns which comprise 27 chromatic, 8 postural and 10 locomotory components. In addition, 18 types of social encounters were identified. Numerous body patterns and components specifically expressed during their interactions were also identified, suggesting that the complexity of the visual stimuli experienced by A. capricornicus, including social cues from their frequent interactions, may contribute to its rich patterning.