Please use this identifier to cite or link to this item:
Type: Artigo de periódico
Title: Shell condition and adequacy of three sympatric intertidal hermit crab populations
Author: Turra, A
Abstract: Shell use in relation to size adequacy and presence of physical damage and encrustation was evaluated and compared among and within three co-existing species of intertidal hermit crab ( Clibanarius antillensis, C. sclopetarius and C. vittatus ) in the intertidal region of Pernambuco Islet, Sao Sebastiao Channel, south-eastern Brazil. Comparisons of shell utilization patterns among species and sexes were made with respect to physical damage (perforations and breakage in aperture and apex), encrustation by other organisms and shell size adequacy. Two adequacy indices were calculated. The visual adequacy index (VAI) was based on the degree of hermit crab retraction into the shells (1 = crab totally retracted and 6 = shield exposed). The shell adequacy index (SAI) was calculated through a comparison of the weight of the used versus the preferred shell. A relationship was found between VAI and SAI with crabs assigned as VAI = 3 occupying optimal shells (SAI = 1), i.e. crabs that could retract and those that could not retract the whole body into shells were in relatively heavier and lighter shells than the preferred ones, respectively. Shells utilized by the hermit crabs were generally undamaged and highly encrusted (except for C. antillensis ) by oysters, barnacles and green algae, features that may reduce the risks of desiccation and predation. The frequent damage to the shell apertures was associated with a high abundance of shell-crushing predators in the studied area. The degree of encrustation as well as the shell adequacy (VAI and SAI) showed intra- and interspecific variation, while the presence of damage differed only among sexes (reproductive classes). In general, the smallest individuals in the populations used relatively heavier shells. Fecundity of the crabs of this assemblage is thought not to be limited by shell use once ovigerous females are occupying optimal shells.
Subject: hermit crabs
shell use
shell condition
shell adequacy
resource partitioning
Sao Sebastiao Channel
Country: Inglaterra
Editor: Taylor & Francis Ltd
Rights: fechado
Identifier DOI: 10.1080/00222930110116020
Date Issue: 2003
Appears in Collections:Unicamp - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
WOS000183336600001.pdf201.25 kBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.