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Effects of embryo energy, egg size and larval food supply on the development of asteroid echinoderms


Trackenberg, Stacy; Richardson, Emily; Allen, Jonathan (2022), Effects of embryo energy, egg size and larval food supply on the development of asteroid echinoderms, Dryad, Dataset,


Organisms have limited resources available to invest in reproduction, causing a tradeoff between the number and size of offspring. One consequence of this tradeoff is the evolution of disparate egg sizes and, by extension, developmental modes. In particular, echinoid echinoderms (sea urchins and sand dollars) have been widely used to experimentally manipulate how changes in egg size affect development. Here we test the generality of the echinoid results by 1) using laser ablations of blastomeres to experimentally reduce embryo energy in the asteroid echinoderms (sea stars), Pisaster ochraceus and Asterias forbesi and 2) comparing naturally produced, variably-sized eggs (1.7 fold volume difference between large and small eggs) in A. forbesi. In P. ochraceus and A. forbesi there were no significant differences between juveniles from both experimentally reduced embryos and naturally produced eggs of variable size. However, in both embryo reduction and egg size variation experiments, simultaneous reductions in larval food had a significant and large effect on larval and juvenile development. These results indicate that 1) food levels are more important than embryo energy or egg size in determining larval and juvenile quality in sea stars and 2) the relative importance of embryo energy or egg size to fundamental life history parameters (time-to and size-at metamorphosis), does not appear to be consistent within echinoderms.


National Science Foundation, Award: 1257039