Mating behaviour and general spawning patterns of the southern dumpling squid Euprymna tasmanica (Sepiolidae): A laboratory study

Abstract

We provide the first detailed description of mating behaviour and multiple mating in the southern dumpling squid, Euprymna tasmanica (Pfeffer, 1884) in the laboratory, as well as details on their general spawning patterns. We found that male E. tasmanica increase the number of 'pumps' (mantle contractions) when mating with females that had recently mated, showing that males are able to determine the recent mating history of females. We also found that at the conclusion of mating, the male's hectocotylus was enlarged. To our knowledge, neither had previously been described in sepiolid squid. Euprymna tasmanica females lay multiple clutches over a large proportion of their lifespan, from 1 to 121 d. There was a considerable variation in the number of eggs produced per female in captivity, ranging from 6 to 646 eggs, and in the number of eggs per clutch, from 6 to 163 eggs. Egg number per clutch declined significantly over the spawning period. Larger females produced larger hatchlings, and egg mass and hatchling mass were significantly correlated. At higher ambient water temperatures the rate at which females produced clutches increased and the size of the eggs laid decreased. © The Author 2013. Published by Oxford University Press on behalf of The Malacological Society of London, all rights reserved.