Reproductive output of Crepidula fecunda females: Distribution of energy in the production of gametes and capsular walls

Abstract

A study was undertaken on the distribution of energy in the reproductive output of Crepidula fecunda Gallardo 1979, a species which provides parental care of deposited eggs during their incubation period. A positive relationship was observed between the shell dimensions and dry tissue weight of the females which was not in turn related to the number of capsules incubated, nor with the size or dry weight of eggs deposited. Positive relationships were observed, however, between the female size and the capsular size and with the numbers of eggs per capsule and per spawning. No significant relationship was observed between the size of the females and the biochemical compositions of the individual eggs, but there was a positive relation between the sizes of the females and the total content of proteins, carbohydrates, and lipids deposited in each capsule wall and in all of the eggs of each spawning. The energetic cost per embryo varied from 0.045 to 0.049 J/embryo in females from 0.5 to 3.5 g tissue dry weight, respectively. Of the total energy invested per spawning, between 92 and 98% was in the eggs, and 2-8% in the capsular walls. Thus, parental care was relevant to the distribution of energy in the reproductive output, favouring production of gametes rather than of protective structures such as capsular walls.