Abstract
For benthic octopuses, shelter utilisation is a common behaviour to defend their vulnerable soft bodies against predators. Furthermore, most species of octopus exhibit egg-care behaviour, and the brooding females often attach their egg masses on the inside of the shelters to defend their eggs securely. The type of shelter is therefore a matter of concern for brooding females, affecting their reproductive success. This study aimed to investigate the shelter preference and utilisation behaviour of the small benthic octopus Amphioctopus fangsiao. Five types of shelters, including empty shells of bivalve Saxidomus purpurata and gastropod Rapana venosa, and different-sized artificial pottery pots, were introduced into the aquaria where eight female octopuses were individually reared. The types of shelters utilised by the females were recorded twice a day until they started spawning (observation period, 12–28 days). Six females with a body weight (BW) ranging from 68 to 125 g utilised the gastropod shells most frequently, and four females attached their eggs to the inside of the shells. Characteristic shell-wearing behaviour like that of live gastropods was observed for these females. Meanwhile, large two females with 135 and 182 g BW selected the largest artificial pot for spawning, suggesting a body size-dependent shelter preference.
