Meeting Abstract

89.1  Friday, Jan. 7  Camouflage and chromatophores in the open ocean: transparency and body patterning in the mesopelagic octopus Japetella ZYLINSKI, S; Duke University s.zylinski@duke.edu

Coleoid cephalopods (cuttlefish, squid and octopuses) are renowned for their ability to rapidly change their body patterns, which they use in a range of complex visual behaviors including predator-specific threat responses, intraspecific signaling, and dynamic camouflage. Body pattern changes are mainly achieved via the expression of numerous intradermal chromatophores, which are under direct neural control and are primarily visually driven. The types of cues and stimuli used by shallow water benthic species such as the common cuttlefish Sepia officinalis to determine the appropriate body pattern has been extensively studied both in the lab and in the field. Yet many cephalopods inhabit the open ocean, where little is known about their use of dynamic body patterning. Japetella is a small mesopelagic octopus, juveniles of which are virtually transparent, a common method of camouflage in the open ocean utilized by a wide range of taxa including fish, crustaceans and cnidarians. However, Japetella is also able to rapidly expand numerous chromatophores enabling it to dynamically alter its degree of transparency. Given that pelagic waters lack the visual structure of the benthic habitat, what cues cause this octopus to express these chromatophores, given that this seems to compromise its camouflage? Here I present findings from behavioral experiments testing the body pattern responses of Japetella to various stimuli. I show that in this octopus chromatophores are primarily expressed in response to perceived threats. I compare the use of cephalopod dynamic body patterning in different visual environments, and discuss how this related to the visual ecology of the animal and its predators.