The title on this Adelaide Now article pretty much says it all: "Sister geckos doing it for themselves." Researchers studying the invasion of the Asian mourning gecko (Lepidodactylus lugubris) in Australia discovered that all the populations there are female. The female geckos have been reproducing by parthenogenesis, where eggs develop into normal adult females without fertilization by a male. Apparently males do exist but they are rare, and none are known in Australia. With no need for a partner in order to reproduce, the lizards have been reproducing quite rapidly, and researchers are concerned that they are colonizing new areas where native (sexually reproducing) geckos are normally found.
Bonus points to the AAP for using the gecko's scientific name. In case you missed it last week, here's a link to the ISW's an invasive gecko photo gallery.