LIFE-HISTORY AND DIET OF PLEUROBRANCHAEA-MECKELII (OPISTHOBRANCHIA, NOTASPIDEA)

The life history and diet of the notaspidean opistho-branch Pleurobranchaea meckelii Leue, 1813 were studied using preserved specimens from the North Tyrrhenian Sea (Mediterranean). Yearly variations of size were inferred from seasonally-grouped data of radular length, foot length and dry weight. Sexual maturity was revealed by the presence of the pedal gland. Life history reconstruction suggested a biennial cycle with benthic recruitment in winter, reproduction through summer and autumn, post-spawning overwintering and possible iteroparity. Weight perturbances occurred during the reproductive period, probably due to reduction in feeding activities. Analysis of stomach contents showed opportunistic carnivorous behaviour, including scavenging and cannibalism. Cnidarians were the preferred prey throughout the year. Results have been compared with the sparse literature data on notaspideans and with more abundant information concerning allied nudibranchs.