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SEPG 2091 - Date Awarded 2002
The Importance of Area, Isolation and Habitat Quality on an Endangered Butterfly on the Isle of Wight.
James J. Bell
Abstract
The epibiont communities encrusting gastropod and hermit crab (Pagurus bernhardus) inhabited shells were investigated at three sites on the south coast of Wales. Hermit crabs were found to inhabit a number of shell types, although the majority (92.6%) were using Nucella lapillus shells as a temporary home. Communities found encrusting gastropod inhabited shells (Nucella lapillus) were characterised by lower species richness compared to shells inhabited by hermit crabs. A greater abundance of epibionts was seen on all shell types during the summer months compared to the winter, although community composition remained the same. Disparities in the community composition of epibionts on shells were attributable to differences in gastropod (mainly open rock) and hermit crab (mainly rockpools) microhabitats. Differences were found in the sizes of Nucella lapillus shells utilised by hermit crabs compared to live gastropods. The mean size of shells inhabited by hermit crabs was larger than the live gastropods, although the reason for such a difference was unclear. Shell selection experiments demonstrated that hermit crabs preferred encrusted shells, although they showed little direct interaction with the epibionts (e.g. feeding upon them when starved).It is considered that the presence of epibionts may act as camouflage, since an energetic cost is associated with carrying encrusted shells and unless some benefit was obtained by hermit crabs they might be expect to prefer clean shells. Considerable lateral hermit crab migration (along the shore) was observed (over a single springs-neaps cycle) increasing the dispersal potential for shell epibionts.
Paper Publichsed in Molecular Ecology (2005) 14, 3525 - 3530
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