Energetic Content of Eggs, Larvae, and Juveniles ofFlorometra serratissimaand the Implications for the Evolution of Crinoid Life Histories

Summary This is the first report of egg, larval, and juvenile energetic content in crinoids. Florometra serratissima (A.H. Clark) produces a nonfeeding larva with an unusually low level of parental investment per offspring. The mean egg volume was 7.42 × 106μm3. The eggs contained an average of 4.47 × 10−2 joules egg−1. The mean energetic density of the eggs was 6.02 joules mm−3. There was a loss of 3.61 × 10−2 joules individual−1 (81% of initial content) during the 25 day lecithotrophic period of the pelagic doliolaria and the prefeeding, benthic cystidean. As a result, the pentacrinoid juveniles contained very little organic material (0.86 × 10−2 joules individual−1), and might suffer high mortality rates as a consequence. These results raise a number of questions about the adaptiveness and the evolution of crinoid life histories.