Grosberg - Mating Systems and Family Conflicts in a Marine Snail

Mating Systems and Family Conflicts in a Marine Snail

Rick Grosberg

Center for Population Biology, University of California, Davis, CA 95616, USA, rkgrosberg@ucdavis.edu

Few groups of organisms encompass greater diversity in mating systems, parental care, and sibling interactions than gastropods. Why do females provide post-zygotic parental care in most species, males in others, and both parents in a few? Why do siblings of some species cooperate extensively, whereas others try to kill and consume each other? Are there predictable associations between patterns of parental care and the nature of interactions among siblings? How are multiway conflicts of interest among family members resolved? The mating system, because it controls patterns of relationship among family members, is one of the keys to answering such questions. Solenosteira macrospirais a buccinid whelk whose reproductive biology embodies multiple forms of family conflict, and, consequently, offers an exceptional opportunity to explore the constraints and opportunities for resolving such conflicts of interest. S. macrospira females mate multiply, and package offspring in capsules, each containing 200-300 siblings. As in other 'neogastropods', there is often extensive predation on sibling eggs, zygotes, and embryos within egg capsules. Quite remarkably, female S. macrospira(and perhaps other closely related cantharids) oviposit almost exclusively on males (>98%), and virtually never on conspecific females or other objects. Brood carrying is risky to males, because it increases their vulnerability to predators; but, it is also essential for brood survival. In this talk, I will analyze the effects of the mating system on the evolution of male parental care and the resolution of parent-offspring and sibling conflict in this, and other, polyandrous species.