Ventilation rate and copulation in Octopus vulgaris

Abstract

Typically three events occur when Octopus vulgaris Cuvier mates. The male inserts its hectocotylus into the mantle cavity of the female; the hectocotylus and the bodies of the male and female become quiescent; and the female increases its ventilation rate about 2.5 times, on the average, above its precopulatory base rate. It is hypothesized that the increased ventilation rate of the female provides the stimulus to the male to transfer its spermatophore to the oviduct. Since the insertion of the hectocotylus and the female's increased ventilation rate may be dissociated, it is suggested that copulation be defined as the attachment of the hectocotylus to the oviduct. A conditioned ventilation-rate increase in the female was observed with repeated testing. Observation of arching and pumping movements of the male as well as measurements of its ventilation rate before and during copulation indicate that only a few spermatophores are transferred per copulation.