Marbled crayfish, an asexual species of crayfish, are doing very well around Madagascar as discovered by Dr. Julia Jones. Reproduction without sex can be more efficient in the short term, while endangering the species in the long term (from Economist ).
In 2005, Matthew Goddard from University of Auckland could report how his team had found evidence that sex speeds up evolution. They experimented with a sexual and asexual version of otherwise identical strains of yeast, monitoring their growth and survival across harsh and benign environments. It turned out that sex did not matter in benign environments, while the sexual strain did much better in the harsh environment.
Early this year, biologists working in Madagascar were shocked to discover that Procambarus 'Marmorkrebs', the world's only known parthenogenetic decapod, had become established in brick pits and rice fields around the capital. I am working with colleagues at the University of Antananarivo (Jeanne Rasamy and Olga Ravoahangimalala) carrying out preliminary research on the rate of spread, the level of risk to biodiversity and agriculture and investigating possible ways of controlling the invasion.
National Geographic - Nature