‘Octopus’ parvus, bean octopus

Gleadall, Ian G.;Che, Leo J.;Hutchinson, Neil

Abstract

‘Octopus’ parvus (Sasaki, 1917) is a small species with a thumb-sized body (maximum mantle length to 40 mm) restricted in distribution to the crevices and pools of rocky intertidal shores on the coast of western Kyushu, Japan. It is an intermittent terminal spawner: the females lay 200-300 (mean 220) relatively large eggs (length 5-6 mm) in daily clutches over about 3 weeks between December and February, from which benthic young hatch directly. Hatching occurs during March to May, with a peak in early April. Males mature earlier than females and are smaller, producing a large number of spermatophores (> 270). The typical mating style observed is ‘male-on-top’, with the male mounting and completely enveloping the female from above, except for usually leaving her head and eyes free. Mating occurs from November to January and copulation was found to last for a mean of more than 3 h in laboratory pairings (once, more than 9 h), with a spermatophore being passed once every few minutes. Embryonic development took around 50 days at 19-20°C and in general the stages and timing resemble those of Amphioctopus fangsiao, another large-egged species. ‘Octopus’ parvus feeds on crustaceans such as hermit crabs, shrimps, amphipods, isopods and shelled molluscs. Some females in captivity ate their own eggs, possibly as a result of the stress of confinement. The suckers of ‘O.’ parvus have a markedly tenacious grip (perhaps related to its intertidal habit), which can sometimes render it difficult to handle in captivity. However, it responds well to anaesthesia with ethanol solution and because of its small size and general hardiness is eminently suitable as a laboratory animal.

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Octopus Biology and Ecology

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9780128206393

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Academic Press

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London, United Kingdom

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DOI

10.1016/B978-0-12-820639-3.00023-6