Notes On the Behavior of Euprymna Scolopes (Cephalopoda: Sepiolidae)

Abstract

18 individuals of the sepiolid Euprymna scolopes were collected in Kaneohe Bay, Oahu, Hawaii. They were observed in the laboratory for a brief period. They were found to be non-gregarious and primarily nocturnal. It was possible to study feeding and defensive behavior. The species seems to prefer shrimps as prey. It is often cryptic. Among the adaptations for crypsis are color changes to match backgrounds (substrates), sand burrowing, and the cementing of sand grains to the back of an individual itself. The grains presumably are held in place by adhesive secretions of the skin. The captive animals also produced patterns which were conspicuous rather than cryptic. They were highly visible, occasionally intricate, combinations of light and dark. Some of them were distinctive. A single copulation was peculiar in certain respects (the spatial positions of the performers), but reminiscent of true cuttlefishes of the genus Sepia in other respects (color displays of both male and female). The phylogenetic implications of these observations are far from clear. On the behavioral evidence, Euprymna could be either a squid-like cuttlefish or a cuttlefish-like squid. It does not show any particular resemblance to Idiosepius, another supposed relative of Sepia.