Shell use, population structure, and reproduction of the hermit crab, clibanarius virescens (Kraus, 1843) at Cape Recife, South Africa

Abstract

Clibanarius virescens (Krauss, 1843) is one of the most common and abundant hermit crabs in South Africa and in the Indo-West Pacific region, but little is known about its population structure or breeding in Africa. Cape Recife, South Africa, is the south-western limit of its distribution and was sampled over a 13-month period to determine shell use, population structure, reproductive output and breeding period of C. virescens. Shells of 17 gastropod species were found in use with Burnupena lagenaria predominating (73.4% of shells used). Males and females appear to partition the shell resource. Males use larger shells of the same types as females, but also use different suites of shells. The sex ratio is 1: 1.77 in favour of females, but males dominate the largest size classes. The breeding season occurs from mid-December to mid-July and ovigery correlates closely to sea surface temperature. Clutch size correlates strongly to crab size and shell volume. The population of C. virescens at Cape Recife has similar patterns of shell use as at other localities in Africa, but shows much larger clutch sizes than previously recorded in South Africa. This indicates that its life-history strategy at Cape Recife may differ from that at other localities within its range. © 2012 The Crustacean Society.