Did you know Sacculina are a type of parasitic barnacle that castrates crabs?

The female Sacculina seek out crabs and cement themselves to their shells. They go through multiple molts as they transform into a kentrogon, which is basically a biological syringe.

Did you know Sacculina are a type of parasitic barnacle that castrates crabs?

Their early life is very similar to most barnacles, they’re free swimming larva that look for a place to cement themselves then molt into a new form.

Unlike most barnacles they don’t transform into a fixed adult form on the side of a boat.

The female Sacculina seek out crabs and cement themselves to their shells. They go through multiple molts as they transform into a kentrogon, which is basically a biological syringe.

The needle of that syringe pierces the crab and injects infectious tissue from the barnacle into the crab then the kentrogon dies.

This tissue is so shapeless that it’s cells can travel through the bloodstream of the crab in a single file line if need be. It migrates into the crabs body and starts growing tendrils around the crabs nervous system, digestive organs, muscles and endocrine systems.

It takes control of the host crab and shuts off it’s ability to grow, molt, regenerate and reproduce. It grows an external body where the crabs own eggs would incubate. Male Sacculina have no adult phase, instead as larvae they inject cells into the external body of the female that produce sperm for her to fertilize her eggs with.

The female crabs are sterilized by the parasite but controlled as they are they still act as if they are mothering their own eggs.

They climb onto a high rock and release the parasite’s larvae while helping to spread them into the water the same way they would their own offspring. If the parasite takes over a male crab they simply turn him female before producing eggs, which the infested crab then spreads.

These barnacles are totally unrecognizable as crustaceans in there adult parasitic form.