Amazon Molly - An All Female Species
Similar to the Amazon Warriors from Greek mythology, the Amazon molly (Poecilia formosa) is a species of fish that is considered to be all female.
Although the females must mate with a male from another species (as sperm is needed to induce embryo growth), the male’s genetic material is not incorporated into the diploid eggs of the mother. As a result, the offspring are clones of the mother.
The species most likely arose from the hybridisation of two other species of molly. The asexual nature of its reproduction benefits the fish in that it has essentially twice the reproductive output in each brood of offspring (as twice as many breeding females are produced compared to a half male half female brood).
Image © President and Fellows of Harvard College