Sex- and Size-Dependent Mating Tactics in a Natural Population of Shore Crabs Carcinus maenas

Abstract

The aim of this study was to characterize sex- and size-dependent mating tactics and their importance in a competitive mating system, where time and space are limited. A natural population of shore crabs Carcinus maenas L. was chosen for this purpose. Over 2 years, the population structure was investigated from May to September, which includes the 1-month-long mating season. Individual marks, lasting for several moults, were branded on 591 crabs. Females, all roaming transients, were outnumbered by the males. Most receptive females entered a limited part of the study area just before moulting, creating a hot spot for the males, which congregated in the area weeks before the first females entered. The reason for choosing a mating ground is not clear, but the females should benefit from easy location of males