Field observations of mating in Octopus tetricus Gould, 1852 and Amphioctopus marginatus (Taki, 1964) (Cephalopoda: Octopodidae)

We present observations of mating by Octopus tetricus Gould, 1852 and Amphioctopus marginatus (Taki, 1964) in the wild. Males of both species mated in the open using the ‘reach’ position, however one male O. tetricus also incorporated the ‘mount’position when copulating with a smaller female. A small male Octopus tetricus copulated by stretching the hectocotylus (= mating arm) over rugged terrain, to a larger female. Direct evidence confirms the existence of inter-sexual aggression during mating in this species. We observed a male A. marginatus mate at close proximity to the smaller female, with minimal stretching of the hectocotylus, and with no evidence of aggression.