Sea Slug With ‘Disposable Penis’ Grows New Reproductive Organ After Sex

A very unusual sea slug with a disposable penis will shed the organ after having sex. Although this sounds rather unfortunate, a new one will take its place within 24 hours.

Chromodoris reticulata is a species found in the Pacific Ocean. According to BBC News, Japanese scientists observed this unusual process in action while studying the sea slug’s mating behavior. Their research was published in the latest issue of Biology Letters.

National Museums Northern Ireland curator Bernard Picton said the slug has both male and female sex organs.

Picton explained:

“The general apparatus is on the right hand side of the body. So two nudibranchs come together and one faces one way and one faces the other way, with the right hand side of their bodies touching.

“The penis from one fits into the female opening of the other one, and the penis from that one fits into the female opening of the first one, if you see what I mean. They are both donating sperm to the other one.”

According to Discovery, these sea slugs are referred to as “simultaneous hermaphrodites” due to the way they reproduce. As for the disposable penis, lead study author Ayami Sekizawa said it simply “falls off.”

Scientists said regrowth seems to take place within 24 hours. Sekizawa explained that some sea slugs observed in the study copulated three times over the course of three days.

LiveScience explains the disposable of the penis is not unlike a gecko losing its tale. However, only the extended part of the organ is cast aside. The portion that remains immediately begins growing new cells to replace what was left behind.

Over the course of their research, scientists said the slugs had sex roughly 31 times. Although having a disposable penis sounds complicated, apparently it doesn’t slow down your love life.

[Image by Bernard Dupont]