Transgender animals after collisions

Body contact can cause a male sea snail to quickly transform into females.

Many animals change their sex at a time of life, usually after reaching a certain size. Sea snails (slipper limpet) were born with male sex and became adult females.

However, new research by US scientists indicates that when two males are close to each other and collide, the adult will move transsexuals sooner than the small one. Physical contact is the agent that makes it transgender. The study is published in the journal The Biological Bulletin in early December.

Tropical sea snail has a scientific name is Crepidula cf. marginalis, living under rocks in intertidal areas along the coast. Their food is plankton and the seeds in the water. This animal is concentrated in groups. Each group consists of large females and one or two smaller males clinging to the females' crust.

Sea snails clinging to rock seams.(Photo: Rachel Collin).

Male sea snails have a relatively large penis, sometimes as long as the body, protruding on the right side of the head. This extended part will extend and slip under the female shell to reach the genitalia. When a sea snail changes its sex, the penis gradually shrinks, then disappears with the development of the female genitalia. Scientists believe that this type of sex change is beneficial because larger females can produce more eggs while small males still produce abundant sperm, which require less energy than spawning. egg.

In the experiment, two males of different sizes were placed in small cups containing seawater. In some cups, they are touched, while with the remaining cups, a net separates them but still allows water to flow through. As a result, large sea snails grow faster and transform into females sooner after experiencing exposure.

Sea snails are animals that only reside in one place and have poor visibility. Therefore, scientists believe that their behavior is influenced by chemicals in the water. But this study shows they have a stronger response to interactions or body signals.

"I was very surprised by this finding. I used to think transgender sea snails relied on domestic signals. But research reveals that they really have a complex reaction to each other," said Rachel Collin, the scientist. studied at Smithsonia Tropical Research Institute, USA, co-author of the study said.