Characterization of the occupied shells by the hermit crab Clibanarius vittatus (Decapoda, Diogenidae) at Baixio Mirim tideflat, Guaratuba Bay, southern Brazil

Sara R Sampaio,Setuko Masunari

doi:10.1590/s0001-37652010000400005

Abstract

A characterization of the occupied shells by the hermit crab Clibanarius vittatus was carried out. Hermit crabs were collected in the intertidal zone, during the low spring tide monthly from April 2005 to March 2006. They were sexed and their cephalothoracic shield length (CL) was measured. Shells were identified, dried, weighed and the aperture length (AL) and width (AW) were measured. 1187 crabs were collected (949 males, 216 females and 22 intersexes), which occupied 12 species of gastropod shells. Stramonita haemastoma, Olivancillaria urceus and Dorsanum moniliferum made up 96.55% of the total shell species. Male hermit crabs attained significantly larger sizes than females; therefore, males occupied a wider spectrum of shells in size and weight. A stronger correlation ratio was obtained between CL and AW of S. haemastoma. Last whorl with a rounded shape and a spacious inner area is a common feature of all shell species most frequently occupied by this hermit crab where it occurs. The successful establishment of C. vittatus at Baixio Mirim is mainly due to the appropriately shaped and wide range of size of S. haemastoma shells that were most often occupied by the hermit crabs of the studied population.

Highlights

Hermit crabs are anomuran crustaceans that use empty shells of gastropods as a shelter
Hermit crabs occur individually or in groups of 5-10 crabs either in the vegetated areas or in non-vegetated ones in Baixio Mirim tideflat, from where they were collected during low spring tides, monthly from April/2005 to March/2006
The remainder shells were occupied with less than 1% each one, and altogether they did not sum up 4% – Achatina fulica (Bowdich, 1822), Buccinanops lamarckii (Kiener, 1834), Cymatium parthenopeum (Von Salis, 1793), Chicoreus (Siratus) senegalensis (Gmelin, 1791), Olivancillaria steeriae (Reeve, 1850), Olivancillaria uretai Klappenbach, 1965, Semicassis granulatum (Born, 1778), Polinices hepaticus (Röding, 1798) and Zidona dufresnei (Donovan, 1823) (Table I)

Summary

Introduction

Hermit crabs are anomuran crustaceans that use empty shells of gastropods as a shelter. These shells can be acquired from the habitat if empty and available; if not, by removing dead or dying mollusks, once hermit crabs are unable to dislodge alive gastropods from their shells (Rittschof 1980, Bertness 1981, Tricarico and Gherardi 2006). Morphometric characteristics of shells influence their occupation by hermit crabs Among these characteristics are weight (Hahn 1998, Dominciano and Mantelatto 2004, Turra and Leite 2004), size (Bertini and Fransozo 2000, Turra and Leite 2004), opening size (Botelho and Costa 2000, Bertini and Fransozo 2000, Sant’Anna et al 2006a) and architecture and volume (Gherardi and Nardone 1997, Floeter et al 2000, Shih and Mok 2000)

Methods

Results

Conclusion