|Sphaerodactylus elegans of Cuba|
Geckos are some of the most diverse and widespread squamates on Earth. They range in size from the dwarf Sphaerodacylus of the Antilles (16-18 mm) to the (probably) extinct Kawekaweau or Delcourt's Giant Gecko, Hoplodactylus delcourti, of New Zealand (as long as a tuatara and as thick as a man's wrist). Except for a few species, none have eyelids, and most have adhesive pads on their toes that allow them to climb slick surfaces. Some are parthenogenic. A few owe their success partly to humans, and it is these that we consider here today.
Several species of gecko have been introduced to the United States by humans, most accidentally, as stowaways or through the pet and greenhouse trade. One of the most ubiquitous is the Mediterranean House Gecko, Hemidactylus turcicus. Described by Linnaeus in the first edition of his Systema Naturae, it is a yellow-tan, nocturnal, insectivorous gecko about six inches long. Whereas most of our non-native lizards are limited to a few small areas in Florida, H. turcicus can be found in 17 states, from California to Maryland. It isn't continuously distributed across the southern US, but rather locally common in urban sites, due to many separate introductions, the earliest of which occurred in Key West before 1915. One such population is in a middle school in Cary, North Carolina.
|Bags of geckos|
|Super Soaking a gecko off a wall|
Previous research on house geckos has revealed that they inhabit similar areas, both climatically and in terms of microhabitat, in their native and non-native range. A population on the Stephen F. Austin State University campus in Nacogdoches, Texas, ate mostly grasshoppers, moths, and isopods. Their great success in southern North America has been attributed to low predation pressure, little interspecific competition, and a life history which maximizes survival at all ages. House geckos in southern Louisiana are host to native North American parasitic worms, so there is some potential for parasites to regulate populations of these non-native lizards.
|Injecting a gecko with glow-in-the-dark elastomer|
The College of Natural Resources and the Office of Undergraduate Research at NC State University provided support and funding for this project. Thanks to Konrad Mebert, Miguel Landastoy, Alex Morrison, Kevin Durso, and Sandy Durso for photographs.
Davis WK (1974) The Mediterranean gecko, Hemidactylus turcicus in Texas. Journal of Herpetology 8:77-80
Rödder D, Lötters S (2009) Niche shift versus niche conservatism? Climatic characteristics of the native and invasive ranges of the Mediterranean house gecko (Hemidactylus turcicus). Global Ecology and Biogeography 18:674-687
Rose FL, Barbour CD (1968) Ecology and reproductive cycles of the introduced gecko, Hemidactylus turcicus, in the southern United States. American Midland Naturalist 79:159-168
Saenz D (1996) Dietary overview of Hemidactylus turcicus with possible implications of food partitioning. Journal of Herpetology 30:461-466
Selcer KW (1986) Life history of a successful colonizer: the Mediterranean gecko, Hemidactylus turcicus, in southern Texas. Copeia 1986:956-962
Life is Short, but Snakes are Long by Andrew M. Durso is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.