Energetic cost of development through metamorphosis for the seastar Mediaster aequalis (Stimpson)

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Rates of oxygen consumption were measured for embryos, larvae and juveniles of the seastar Mediaster aequalis for 76 days post-fertilization. The rate increased from 0.65 nmol O2 ind−1 h−1 at 6 h after fertilization to 2.8 nmol O2 ind−1 h−1 at day 35. Larvae became competent to metamorphose around day 35 post-fertilization and began to decrease their metabolic rate after this time. Metamorphosed juveniles consumed 0.74 nmol O2 ind−1 h−1. Eggs contained 138.6 µg lipid ind−1 and 12.1 µg protein ind−1. Lipid levels decreased in concentration throughout development while protein levels increased slightly. The lipid levels decreased by 88.5 µg from eggs to day 76 larvae, accounting for 3.5 J of energy. Total oxygen consumption to this point was 3.74 µmol O2 ind−1, accounting for 1.84 J. The energetic demand up to day 76 was met completely through the use of lipid reserves. Metamorphosed juveniles expended 0.5 J more than larvae at the same age. Tubes of the polychaete Phyllochaetopterus prolifica were able to induce metamorphosis in M. aequalis larvae and a non-polar extract of these tubes also triggered metamorphosis. Larvae that are delayed to metamorphose can sustain their metabolic rate with lipid reserves for a limited, yet undetermined, period.


This article was originally published in Marine Biology. The full-text article from the publisher can be found here.

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Marine Biology


© Springer-Verlag 2004