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GAMETE TRAITS INFLUENCE THE VARIANCE IN REPRODUCTIVE SUCCESS, THE INTENSITY OF SEXUAL SELECTION, AND THE OUTCOME OF SEXUAL CONFLICT AMONG CONGENERIC SEA URCHINS
Author(s) -
Levitan Don R.
Publication year - 2008
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2008.00378.x
Subject(s) - biology , gamete , polyspermy , sexual selection , human fertilization , sexual conflict , strongylocentrotus purpuratus , sperm , reproductive success , ecology , selection (genetic algorithm) , reproduction , sperm competition , zoology , sea urchin , demography , in vitro fertilisation , botany , population , fishery , genetics , embryo , artificial intelligence , sociology , computer science
Sea‐urchin species differ in susceptibility to sperm limitation and polyspermy, but the influences of gamete traits on reproductive variance, sexual selection, and sexual conflict are unknown. I compared male and female reproductive success of two congeners at natural densities in the sea. The eggs of the species occurring at higher densities, Strongylocentrotus purpuratus , require higher sperm concentrations for fertilization but are more resistant to polyspermy compared to S. franciscanus . Both species show high variance in male fertilization success at all densities and high variance in female success at low densities, but they differ in female variance at high densities, where only S. franciscanus shows high female variance. The intensity of sexual selection based on Bateman gradients is high in males of both species, variable in S. franciscanus females, and low in S. purpuratus females. Strongylocentrotus franciscanus females experience sexual selection at low densities and sexual conflict at high densities. Strongylocentrotus purpuratus may rarely experience sperm limitation and may have evolved to ameliorate sexual conflict. This reduces the variance in female fertilization, providing females with more control over fertilization. Sperm availability influences sexual selection directly by determining sperm–egg encounter probabilities and indirectly through selection on gamete traits that alter reproductive variances.