WEDNESDAY, Dec. 20 (HealthDay News) -- When it comes to males, it seems female Komodo dragons can take 'em or leave 'em.

That's because female Komodo dragons don't need males to produce offspring, according to an article in this week's issue of the journal Nature.

The article describes parthenogenesis in two female Komodo dragons at zoos in the United Kingdom. Parthenogenesis, the production of offspring without fertilization by a male, is rare in vertebrate species.

Flora, a Komodo dragon at Chester Zoo, used parthenogenesis to produce a clutch of 11 viable eggs earlier this year. Three of the eggs were crushed during incubation and provided researchers with embryonic material for DNA tests. The remaining eight eggs are developing normally and are expected to hatch in January 2007, the article said.

Another female Komodo called Sungai -- a resident of the London Zoo -- produced four offspring more than two years after her last contact with a male. She later produced more offspring after mating with a male.

The authors of the article said these cases of "reproductive plasticity" suggest that female Komodo are able to switch between asexual and sexual reproduction, depending on the availability of a male mate. This has implications for breeding this endangered species in captivity.

Most zoos keep only female Komodo dragons, while males are shipped around to different zoos for breeding. But the authors of this article suggest that it may be best to keep male and females together at zoos in order to avoid parthenogenesis in females, which they say decreases genetic diversity.