The Bynoe's gecko (Heteronotia binoei) is endemic to Australia and occurs across much of the country including here in Western Australia (see image below - taken in the Pilbara in 2015). The species is irregularly patterned with spots and bands, but can be variable in appearance ranging from greys to reddish-browns. Bynoe's gecko is typically active at night and primarily terrestrial (as opposed to arboreal), feeding on a range of insects and other invertebrates.
When it comes to breeding biology, this is where this gecko gets really interesting. Some populations are diploid (two sets of chromosomes) consisting of both males and females, which reproduce sexually with females laying eggs from September to January. However, other populations are only female and are triploid (three sets of chromosomes). These all female populations reproduce asexually without the need for males, resulting in genetic clones. This process is known as parthenogenesis, from the Greek parthenos, meaning virgin, and genesis meaning creation. Now although parthenogenesis is not uncommon globally, Bynoe's gecko is one of the only known species of Australian reptile to reproduce through this process (a skink that undergoes parthenogenesis has also been identified in Central Australia). The parthenogenic populations are typically found in the Central and Western deserts of Australia, however, interestingly these populations often overlap with the diploid populations. Research by Mortiz (1989) helped shed light on this, as it was observed that the triploid parthenogenic populations arose from a hydridisation event between two genetically distinct populations of Bynoe's gecko. Now despite reproducing asexually the genetic diversity in the all female populations is higher than most parthenogenic reptiles. It has been suggested that this may be explained through multiple hydridisation events. More recent research by Kearney et al. (2005) has also shed some light on the abilities of these all female populations. The findings suggest these populations appear to be the "wonder women" of the gecko world. In terms of oxygen consumption rates, endurance and aerobic speeds, the parthenogenic all female populations out-compete the sexually reproducing populations by up to 50%. Although they appear to have a competitive advantage over their sexually reproducing counterparts, they are not invincible. The all female populations have been documented to suffer from higher deformity rates than their sexually reproducing counterparts and are more susceptible to infestation from parasitic mites. So although they can keep the population ticking over without males, the lack of genetic mixing in the population comes at a cost. Further reading & resources
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AuthorMy name is Garry and I am extremely passionate about the environment. I have completed my BSc. Conservation and Wildlife Biology with First Class Honours and have worked in the Environment sector since 2009. Archives
September 2019
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Photos used under Creative Commons from sean.kelleher1, BioDivLibrary, BioDivLibrary