Journal of the Marine Biological Association of the United Kingdom

Short Communications

Synchronous Penis Shedding in the Rough Periwinkle, Littorina Arcana

C. Dythama1, J. Grahamea2 and P. J. Milla2

a1 Department of Biology, University of York, PO Box 373, York, YO1 5YW.

a2 Department of Pure and Applied Biology, University of Leeds, Leeds, LS2 9JT

Penis size and morphology of an oviparous species of rough winkle Littorina arcana Hannaford Ellis (Gastropoda: Prosobranchia) was studied at Robin Hoods Bay on the English east coast. Monthly collections were made over a two year period from August 1987 to August 1989 and again from May to December 1993. Number of penial glands was recorded and a six point scale was used to quantify penis maturity. Results indicate that male L. arcana shed their penes in summer and regenerate a new one during the following 12–20 weeks. Male L. arcana in captivity shed penes in July but not in November. The significance of penis shedding and the differences in reproductive seasonality between L. arcana and its ovoviviparous sibling species L. saxatilis is discussed.