Purple sea urchin, Strongylocentrotus purpuratus, are broadcast spawners.
Empirical and theoretical exploration of this trade-off in broadcast spawners has
focused heavily on the role of sperm availability. In contrast, the particular manner
in which egg concentrations alter both fertilization and polyspermy remains less explored.
These data are from a laboratory experiment with a factorial design (six sperm concentrations x
four egg concentrations replicated across multiple male-female pairs), to measure
fertilization and polyspermy of
purple sea urchins. Data were used to evaluate the impact of egg concentration
on fertilization, and to explicitly test for random versus nonlinear sperm-egg collision
rates. A new dynamic model was developed that expands upon existing models. Observations of
fertilization and polyspermy were also used to parameterize and compare the performance of
existing models that included random or or nonlinear collision parameters by utilizing
several different basic model forms. For more information, see paper with published results
or data set methods.
Results for these data are pulished in Okamoto. D. K. 2016 Competition among eggs shifts
to cooperation along a sperm supply gradient in an external fertilizer. The American Naturalist. 187:5, E129-E142. DOI: 10.1086/685813