Local Races in Lugworms (Arenicola marina (L.))

Abstract

THE spawning of Arenicola marina (L.) on the shores of the British Isles occurs during the last three months of the year, but within these limits there are striking variations of spawning time from place to place. Each local population of lugworms appears to have a characteristic spawning period which occurs at much the same time every year (Duncan, Proc. Zool. Soc., in the press). The differences in the dates of spawning may indicate a tendency towards genetic variation between different populations; they would also encourage such differentiation. There are, of course, environmental differences between beaches which may influence the time of spawning, but it is difficult in this way both to account for the observed similarity of the spawning periods of lugworms at Dale Fort, Wales, and Whitstable, Kent, and for the fortnight's difference in the spawning of worms living as close together as Port St. Mary and Derbyhaven in the Isle of Man.