Sacculina carcini

[3] The Kentrogonida order contains the Sacculinidae family, known for their ability to induce parasitic sterilization in crabs.

[2][3] The parasite's range largely coincides with that of this host, which is usually the coasts of Western Europe and North Africa.

The green crab, however, has been expanding its range and has become established in both North and South America, Southern Africa and Australia, so it is possible that the parasite is now present outside its natural territory.

They take over the stomach, intestines, and nervous system to absorb nourishment and enable the parasite to control the behavior of its host.

If the parasite is experimentally removed from the host, female crabs will usually regenerate their ovaries, but in males, sex change takes place and they develop ovarian tissue.

However, the female, including the externa, can live for as long as the crab host survives, perhaps one or two years.

The Sacculina carcini is known to control the population size of their hosts, like the Green crab, by making many of them infertile.

Sacculina carcini can be considered as a potential biological control agent for Carcinus maenas, known as the invasive green crab species.

One possible solution could be to distribute the parasite only in low populations of C. maenas, enabling a faster death rate compared to other native species.

Rhizocephala. A–H, life cycle stages and larval morphology of selected Rhizocephala. A, Nauplius larva of Sacculina carcini . B, Male cyprid of S. carcini. C, Settled male cyprid of Lernaeodiscus porcellanae in the mantle aperture of a virginal female reproductive body (externa). D, Male trichogon of S. carcini dissected from the mantle cavity of a virginal female externa. E, Female cypris of S. carcini. F, Kentrogon of S. carcini, inside the empty cuticle of the spent female cyprid, in the process of injecting the primordial parasite. G, Vermigon of Loxothylacus panopaei . H, Scanning electron micrograph of Peltogaster curvata, showing the reproductive sac (externa) connected to the ramified internal root system. I-P, Diversity of Rhizocephala externae on various hosts.