Egg production and shell relationship of the hermit crab Pagurus brevidactylus (Anomura: Paguridae) from southern Brazil

Abstract

AbstractThe present study characterised the fecundity of the hermit crab Pagurus brevidactylus as well as the influence of shell type and size on fecundity using the morphometric relationship. Ovigerous females were collected monthly from January to December 1999 in the infra-littoral region of Anchieta Island, using scuba-diving methods. Only the ovigerous females with eggs in the early phase of development were selected for the fecundity analysis. The number of eggs carried by individuals of several sizes (SL, shield length), condition of development, and egg size were determined. A high percentage (77.0%) of ovigerous females with eggs in the early phase of development were captured, with a low frequency (9.2%) of females with eggs in the final stage of development. A total of 157 females with recently produced eggs were analysed. Individual fecundity ranged from 27 (SL = 1.25 mm) to 1075 eggs (SL = 3.19 mm) and mean fecundity was 158 ± 119 eggs. The number of eggs produced during spring was significantly higher than those produced in the other seasons of the year. Considering the two shells most occupied by P. brevidactylus (C. atratum and M. nodulosa), the highest fecundity was observed for ovigerous females occupying M. nodulosa ones, showing that shell type can influence the reproductive potential of ovigerous females. The reproductive aspects of P. brevidactylus were related to the shell species occupied and to strategies developed to compensate for interspecific competition, i.e., continuous reproductive effort and early maturity.