The Asian house gecko (Hemidactylus frenatus) originates from the southern United States of America and Mexico.
The Asian house gecko has an average body length of 6cm and total length (including tail) of 11cm. They are pale pinkish-brown to dark grey, with mottled patterning. Individuals can vary appearance based on the level of physical activity and light exposure (dark with pattern by day; pale and patternless at night). At a distance the Asian house gecko is very similar to the native Dtella, but can be distinguished by a series of small spines or tubercules along back and edges of tail (in its original state) and lower back.
All Asian house gecko toes have claws, but the inner toes of Dtella, are clawless.
They are more readily identified by voice rather than appearance - a loud and distinctive "chuck-chuck-chuck".
The Asian house gecko is Australia's most successful invasive reptile. Once considered to be a benign invader limited to urban areas, recent studies have shown that, as in other parts of their colonised range, Asian house geckos have displaced native geckos from the house gecko niche and have spread into, and become established in considerable densities in, bushland habitat in the Northern Territory and in places such as Mon Repos Conservation Park in Queensland.
Initially confined to the urban coastal regions of the Northern Territory and Far North Queensland, Asian house geckos have shown amazing adaptability and resilience, and are now distributed throughout Qld and NT. The species appears to be continuing its progression southward with established populations in north-east NSW and individuals captured as far south as Sydney.
Originally a tree-living species, Asian house geckoes now thrive in human dwellings and buildings, where their feeding strategy is greatly enhanced by lights that attract insects and flat walls and ceilings upon which prey animals (insects etc.) are concentrated.
Asian house geckos are generalist predators, eating a large variety of prey, including insects, spiders and other small lizards.
Female Asian house geckos lay two eggs approximately every four to six weeks. The large, white eggs are sometimes clearly visible through the body wall of a gravid female's underbelly. In the tropics, the geckos breed year-round, however in sub-tropical and more temperate areas their reproduction appears to take on a seasonal cycle and they do not breed during the winter.
While there are anecdotal reports that the Asian house geckos may be parthenogenetic (not requiring males to breed), there is no scientific evidence to support this. However, experiments have shown that females have the capacity to store sperm for up to six weeks.
Asian house geckos are highly successful stowaways due to their small size and resilience. Their success in spreading is due largely to the nature of their eggs. While most reptiles lay eggs with soft, parchment-like shells that dehydrate rapidly in dry conditions, the Asian house gecko lays round, hard-shelled eggs which are much more resistant to moisture loss.
In Australia, the importation of live animals is controlled by the Environment Protection and Biodiversity Conservation Act 1999 (EPBC Act). Under the EPBC Act, restrictions have been established as a safeguard to protect Australia against exotic pests and diseases that are considered a threat to the Australian environment, economy and the wider community and to protect endangered species from uncontrolled trade which can lead to population decline and extinction of endangered species.
In order to be eligible for import into Australia, animal species must be listed on the Commonwealth Government’s Live Import List under the EPBC Act. However, Asian house gecko is not included in the Live Import List making importation of the species into Australia illegal.
As a reflection of the biosecurity risks it presents, the Asian house gecko is classified as a Prohibited Dealing under the NSW Biosecurity Act 2015. It is an offence to keep or otherwise deal with this species.