Population biology of the hermit crab Petrochirus diogenes (Linnaeus) (Crustacea, Decapoda) in Southern Brazil

Abstract

ABSTRACT. The aim of this study was to provide information on the biology of a subtropical population of the hermit crab Petroc!tirus diogenes focusing size structu re, sex ratio, reproductive period and morphometric relationships. Monthly samples were done between January and December 1995 at Armayao of [tapocoroy , Penha, southern Brazil , using two over-trawls in depths from 6.0 to 10.0 m. A total of 126 indi viduals were collected. Overall sex ratio did not differ from I: I. When the sex ratio was analyzed for each size class, it was skewed for females in the smal lest size classes while males outn umbered fema les in the largest ones. The mean size (cephalothoracic length) of P. diogenes was 30.61 ± 12.52 mm and the size structure of thi s populati on was skewed to the right. Males were on average larger and heavierthan both ovigerous and non-ovigerous females , which, in turn, showed similar sizes and weights. The ovigerous females represented 6 1 % of all females and occurred from January to April and in September and December. The relationship of cephalothoracic length and both cephalothoracic width and crab weight were i ometri c. Both crab size and weight showed a negati ve allometry with shell weight, indi cating that larger/heavier crabs use proportionally lighter shell s than small-sized ones.

Morfometria, Proporcion Sexual Y Selectividad a Conchillas De Gasteropodos De Tres Especies Simpatricas De Cangrejos Ermitaños Pagurus (Decapoda. Anomura, Paguridae) en La Bahia De Ancon, Lima, Peru

“…En esta ocasión sólo predominaron las hembras en P. perlatus (Tabla I). Turra et al (2002) han señalado que en la distribución de tamaños en las poblaciones de pagúridos, los machos son más grandes que las hembras, debido posiblemente a que los machos crecen más rápido que las hembras. Este patrón se encontró para P. villosus y P. edwardsi (Tabla II).…”

“…Los "cangrejos ermitaños" son un grupo de crustáceos adaptados a vivir dentro de conchillas de gasterópodos, condiciones en las que son muy exitosos, desde hábitats terrestres y semiterrestres hasta profundidades de 3.000 m. Aquellos pertenecientes al género Pagurus son de aguas sobre la plataforma y componentes importantes de la estructura de macro-invertebrados, tanto en áreas intermareales y sublitorales alrededor del mundo (Mello 1999;Turra et al 2002;Zúñiga 2002). En el submareal somero de la Costa Central del Perú se encuentran tres especies de Pagurus: Pagurus villosus (Nicolet 1849), P. edwardsi (Dana, 1852) y P. perlatus (H. Milne Edwards 1848) (Del Solar 1972;Quiñe et al 2003).…”

Reproductive apparatus of the male giant hermit crab Petrochirus diogenes (Anomura, Diogenidae): morphology and phylogenetic implications

“…Previous reports have described the larval development (Provenzano 1963(Provenzano , 1968, feeding and chewing structures (Caine 1975), behavior related to shell occupation (Kellogg 1977, Bertini 1997, Bertini & Fransozo 2000a, relative growth (Bertini & Fransozo 1999a), population dynamics (Bertini & Fransozo 2000b), spatial and seasonal distributions (Bertini & Fransozo 1999b), reproductive period (Bertini & Fransozo 2002) and population biology (Turra et al 2002) of this species. Data on the morpho logy of the reproductive apparatus are still scant.…”

Comparative analysis of populational structure of the Hermit Crab Dardanus insignis (Anomura: Diogenidae) in a Subtropical Area of the Brazilian Coast

“…In Brazil, the last decades have been marked by a reasonable number of studies on hermit crabs and anomuran communities (Negreiros-Fransozo & Nakagaki, 1998;Turra & Leite, 2000;Fransozo et al, 1998;2008;Mantelatto & Garcia, 2002) and particular features of each species such as population structure, reproduction, relative growth and shell occupation (Negreiros-Fransozo et al, 1992;Reigada & Santos, 1997;Bertini & Fransozo, 1999a;Garcia & Mantelatto, 2001;Turra et al, 2002;Frameschi et al, 2013). Recent studies have described some features of D. insignis, including the post-embryonic development (Hebling & Mansur, 1995), population dynamics Fernandez-Goés et al, 2005) and fecundity (Miranda et al, 2006).…”