Clownfish do it, wrasses do it, and sometimes even chickens do it. Animals that spontaneously change sex are probably more common than you think. After all, the ability to change the sex ratio of a species based on environmental factors makes way more sense than the system we’ve got going on.
A new study from the Smithsonian Tropical Research Institute examined the ol’ sex switcheroo in one species in particular and found a surprising trigger: touch.
It makes sense for bigger tropical slipper limpets to become female. Because eggs take more energy to produce than sperm, a bigger mollusk will be more capable of reproductive success as a mom than a small one. In fact, females of the species play host to multiple males that live on their backs. But how does a snail’s body know that the time is right to make that change? Some kind of inter-animal communication must occur that “tells” a snail that it has reached the right relative size to become a mom.
STRI staff scientist Rachel Collin and former intern Allan Carrillo-Baltodano, now a predoctoral student at Clark University, found that the snail seems to use physical contact with other members of its species to guide sex change. This came as a surprise to Collin and Carrillo-Baltodano, who were testing the hypothesis that the snails rely on waterborne chemical signaling to guide the changes.
