Reproductive potential of the hermit crab Calcinus tibicen (Anomura) from Ubatuba, Sao Paulo, Brazil

The purpose of this study was to determine egg production by Calcinus tibic en, as well as the influence of shell type on fecundity using morphometric relationships. Ovigerous females were collected at 2-month intervals for 2 consecutive years (from January 1993 to November 1994) along the rocky shor e of Ubatuba. The number of eggs carried by individuals of several sizes(sh ield length), condition of development, and egg size were determined. A tot al of 89 specimens were analyzed. Individual fecundity ranged from 193 (SL = 5.12 mm) to 6,785 eggs (SL = 4.25 mm) and mean fecundity was 1,719.25 +/- 1,199.43 eggs. The lowest mean fecundity values were observed during the s pring. The number of eggs produced per female was large and varied widely a mong size classes. This fact may probably be attributed to multiple or frag mented spawnings and primiparous or multiparous females during the reproduc tive cycle. Shells of 5 gastropod species were occupied by ovigerous female s of C. tibicen. Stramonita haemastoma was the most occupied shell, althoug h Tegula viridula presented the best associations, calculated by regression analysis between the dimensions of the shell and of ovigerous females and fecundity. This shows that shell type can influence the reproductive potent ial of ovigerous females, but not to the point of interrupting it.