![]() The marine whelk snail lives in the intertidal regions of northern Baja California. "This is an indication of all the other things that go into that (mating and child-raising) decision." "What makes this system so cool is that in every other system where males do all the care, the caring father is the genetic father of all those offspring," Grosberg said. The difference is that in almost all other cases the male caregiver is related to the babies he is raising, they said. Among them is the seahorse, according to Grosberg, an evolutionary biologist, and his co-author Stephanie Kamel, a postdoctoral research fellow at UC Davis. There are, of course, other species where the males raise the young. It is a highly unusual circumstance considering that most males in the animal kingdom typically mate with as many females as possible and are pretty much indifferent to the products of the unions. Only 1 in 4 of the babies that the male whelk raises is his own. "Basically, the females have won," said Rick Grosberg, a professor of evolution and ecology at UC Davis, summing up the results of his newest study on the snail published recently in the journal Ecology Letters. Pretty shabby treatment for a guy who carries his penis on his shoulder. “But this study shows that there is more going on there than we thought.The male whelk, known to scientists as Solenosteira macrospira, not only endures shameless promiscuity in his mate, but is then also compelled to carry the products of her dozens of liaisons on his back until they hatch. “Slipper snails don’t move around much, so you don’t really think of them having complex reactions to each other,” Collin said. Surprisingly, slipper limpets turned out to be like fishes in showing a greater response to behavioral interactions or perhaps contact-based chemical cues, than waterborne signals. Slipper limpets, which are sedentary and have poor vision, were initially expected to depend more on waterborne chemical cues, already known to affect other aspects of their behavior. In sex-changing coral-reef fishes, visual, behavioral and chemical cues may all influence switching by individuals that associate with each other. Conversely, the smaller member of a pair that was in contact delayed sex change compared to ones separated by mesh. The larger snails in the pairs in direct contact with their partners grew more quickly and changed into females sooner than those kept apart. In some cups they were allowed to be in contact with one another, while in others a mesh barrier kept them apart while allowing water to pass through. ![]() In experiments, two males differing slightly in size were kept in small cups containing seawater. It is thought that this kind of sex change is advantageous because large animals are able to produce larger numbers of eggs as females, while small males can still produce plenty of sperm (which require much less energy to make than eggs). When a snail changes sex, the penis gradually shrinks and then disappears at the same time that female organs develop. This elongated apparatus is necessary to extend around and under the female’s shell in order to reach her genital opening. Often found in clusters, they occur alone or as pairs or trios consisting of a large female with one or two smaller males riding piggyback on her shell.Ī male limpet has a comparatively enormous penis–sometimes as long as his entire body–which rather incongruously emerges from the right side of his head. When flipped over, they resemble men’s house slippers. Their thin, flattened shells have a built-in shelf. marginalis, live under rocks in intertidal areas along the shore, obtaining food by filtering plankton and other particles from the water. The article, co-authored by Collin and former STRI intern Allan Carrillo-Baltodano, now a pre-doctoral student at Clark University, was published in The Biological Bulletin. Contact, rather than chemical signals released into the water, induces sex change in slipper snails, “Crepidula marginalis,” shown here in their natural, intertidal habitat.
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