Meet the parasite that sterilizes crabs, takes over their bodies, and forces them to raise its babies

Introducing Sacculina carcini

Crab sex slaves?! 

This is the crab-hacker barnacle, which takes over the body and brain of a crab to turn it into a sex slave. 

Basically, what happens is a female larva will find a crab host and push her way inside, creating tendrils that spread throughout the crab, taking over its stomach, intestines and nervous system. This allows the parasite to hack into the crab’s nourishment and take control of its behaviour – hence the name, crab hacker.  

But the story doesn’t end there. The parasite will sterilize its host and then repurpose her reproductive area into “baby-barnacle production facilities.” At this point, the crab is not only being forced to provide food and shelter to the parasites inside her, but she’s also tricked into caring for the eggs like she would her own. 

These eggs will be fertilised by male larvae, and when the eggs are ready to be released, the crab will be instructed to climb onto a rock and release them into the water, and the cycle will begin again. 

If anyone were to see this crab walking about, eating, they could be forgiven for thinking it was any ordinary crab just going about its life. But in reality, this crab’s sole purpose is to serve the parasite and its babies.  

But what happens if one of these crab-hacker barnacles happens to stumble across a male crab, rather than a female?  

Not a problem. They cause the male to essentially undergo a sex change, where his abdomen will broaden, and he’ll develop a pouch to hold the parasite’s young. It’s crazy stuff.  

Yet another example of just how creative nature is when it comes to sex and reproduction.  

If you’re after more crazy nature facts, check out our playlist on our YouTube channel, it’s dedicated entirely to sex in nature.

Read more here: https://www.iflscience.com/the-crab-hacker-barnacle-moves-into-crustaceans-and-changes-their-sex-68436