Who Needs Males?

The Marbled Crayfish is the only species of decapod crustacean that is exclusively female.

This is because they simply don’t need males to reproduce. Instead, they are capable of parthenogenesis and the offspring are genetically identical to the parent (singular).

Parthenogenesis is a natural form of asexual reproduction, where embryos develop from an unfertilised egg without any need for sperm. 

The fact that they can reproduce from a single crayfish however means that they are potentially a very invasive species. 

This is also a concern because they are carriers of ‘crayfish plague’, Aphanomyces astaci, a water mould that can kill crayfish in weeks.