The nudibranch Chromodoris reticulata has a single-use sex organ, from a coil hidden inside the body, with the parts taken out ready to be shed after each mating.
A strange sea snail may give new meaning to the term 'quicky'. Nudibranchs (Chromodoris reticulata) use a detachable penis to increase the frequency of intercourse. This is according to a new study that dealt with the species known as nudibranch
The animal, described in an article published yesterday (February 12) in the journal Biology Letters of the British Royal Society, is the first known to use a detachable, easily regenerated penis.
Nudists are bisexual creatures at the same time, meaning they have male genitalia that they use to fertilize other nudists, as well as female genitalia. However, how they have sex - this question remains a mystery.
Ayami Sekizawa, a biologist from Osaka University in Japan, and his colleagues collected specimens of the nudibranch Chromodoris reticulata while diving off the coast of Okinawa Island. They put 31 pairs of these creatures together in aquariums and watched them mate.
When these nudibranchs mated, they unrolled part of a long penis coiled like a fire hose inside their bodies. The creatures penetrated each other's bodies (as mentioned both are bisexual) with the male genital organ covered with vertebrae pointing backwards - into the body, and after a few tens of seconds to a few minutes of sex, they separate.
Nudibranchs shed their male genitalia (or at least the visible part of them), similar to the way a gecko sheds its tail. After a day, they were ready to mate again, by exposing part of the genitalia that was previously hidden inside their bodies. After intercourse ends on the third day, the coiled part of the penis produces new cells that will eventually become a whole penis again, the researchers estimate.
Because these sea creatures often live in tight groups when sexual competition is intense, the scientists speculate that the use of a detachable penis may give nudism an advantage by allowing them to have sex more frequently, the researchers write in the paper.
Using a detachable penis also allows nudists to scrape out competitors' sperm as they grapple with the difficulty of removing a vertebra-covered penis from the partner's body.
"Chromodoris reticulata may compensate itself for the short-term cost of fewer breeding opportunities caused by the loss of the genital organ with the cultural advantage gained by removing the competitor's sperm in a highly competitive environment," they write.
