MEPS 641:123-134 (2020)  -  DOI: https://doi.org/10.3354/meps13304

ABSTRACT: The eggs of echinoderms with lecithotrophic development provide structural and nutritional materials (lipids, proteins) to complete development without any external sources of nutrition. Previous studies have suggested that a relatively large proportion of the maternal lipid reserves remain after settlement to provision the early post-metamorphic juvenile. Here we examined lipid and protein utilization during lecithotrophic development of the asterinid starfish Stegnaster inflatus which has large (~400 µm diameter), negatively buoyant eggs. S. inflatus produces eggs with a large amount of lipid (mean ± SD: 2047 ± 315 ng egg^-1), with 26% structural lipids and 74% energetic lipids dominated by diacylglycerol ether (DAGE; 66%). Similar amounts of protein were present in the egg (mean ± SD: 2143 ± 157 ng egg^-1), with a lipid:protein ratio of 0.96. Approximately 80% of the egg protein is used prior to settlement. In contrast, 51.0% of the energetic lipids provided in the egg, and 40.3% of the DAGE remain for provisioning of the early juvenile. A review of lecithotrophic development in echinoderms reveals that asteroid, echinoid and ophiuroid species have an excess of 50% of the maternal lipids remaining in the settled post-larva. When considering maternal investment in offspring for lecithotrophic developers, we need to consider energetic use during the short dispersal period, as well as provisioning for post-metamorphic early juvenile life.

KEY WORDS: Asterinidae · Echinodermata · Non-feeding larva · Demersal larva · Larval buoyancy · Lipid · Protein · Maternal provisioning