House Geckos

Living in a tropical climate means living with bugs, they thrive in the humid air and lush growth. Even on the relatively dry side of the island the sheer numbers of insects and other creepy crawlers is daunting. Ants, termites, cockroaches, and much more. We had hoped to leave the giant centipedes and scorpions behind when moving from Arizona, but this was not to be, we have both around the house in Hawai'i.

Dealing with these hordes of insect pests is a constant problem, and spraying gallons of poisons around is not an attractive answer. Most Hawaiian residents quickly realize we have allies, and the smart homeowner learns to encourage the right allies in this battle. The best allies are small, scaly, and can go anywhere in the house, they are constantly on patrol, particularly on the night shift.

Their name is gecko.

Geckos are voracious predators, anything smaller is prey. They will attack, kill and eat cockroaches nearly as large as they are, leaving nothing but bits of wings and the occasional leg behind as evidence of the battle.

In a healthy house the geckos are everywhere, the smallest of crevices can be a home to these little creatures. They scurry all over the outside walls, up and down the siding and under the eves. Windows are a particularly good hunting area as flying insects, attracted to the lights inside, come to the window, only to be ambushed by the waiting geckos. A few will take up housekeeping inside, making their homes in odd corners and in the rafters. They announce their presence with the odd little barks in the night "Tchack, tchack, tchack". Sometimes startlingly loud, these barks proclaim territories and availability to potential mates. The tropical night is rich with echoing barks through the house and across the neighborhood.

These little creatures have become part of the folklore of many tropical regions. Welcomed by almost all cultures they are often considered good luck and welcomed into our dwellings. It does not hurt that geckos are adorably cute, particularly the tiny and delicate hatchlings. Big eyes, bright colors and little splayed claws just appeal to everything humans consider attractive. First welcomed for their appearance, they become considerate house guests, doing their duty of eliminating those house guests we do not want.

Hawaiian culture is no exception, the gecko commonly appears in Hawaiian lore and mythology. The gecko was an incarnation of Mo'o, a magical lizard 'aumakau or guardian spirit who was revered by certain families and believed to offer protection. (1)

There are nine species of geckos that have found their way to Hawai'i,(2) none are endemic to the islands, having arrived from elsewhere. Of these it is likely that four different species either floated to the islands, or possibly came with the Polynesian voyagers, either deliberately or as hitchhikers aboard the great voyaging canoes. These four were present in the islands before the arrival of western seafarers; the Mourning Gecko (Lepidodactylus lugubris), the Stump-toed Gecko (Gehyra mutilata), the Small Tree Gecko (Hemiphyllodactylus typus), and the Indo-Pacific Gecko (Hemidactylus garnottii).

Other gecko species began arriving in the 20th century, these include the Common House Gecko (Hemidactylus frenatus) in the 1940's, the Gold-dust Day Gecko (Phelsuma laticauda) in the 1970's, the Orange-spotted Day Gecko (Phelsuma guimbeaui) in the 1980's. The Tokay Gecko (Gekko gecko) is an even more recent arrival, probably the result of escaped pets and like the Orange Spotted Day Gecko is currently found only on Oahu. The Giant Day Gecko (Phelsuma madagascariensis grandis) has been found in the Manoa Valley and at Pearl Harbor on Oahu, but it is uncertain if this species it truly established. (2)

The early arrivals to the islands were all asexual, meaning that only one animal need make it to the islands to begin laying eggs and spreading into the habitat. This almost certainly made successful colonization more likely. Several of the later geckos to arrive are bisexual. The spread of geckos throughout the Pacific and to the various island habitats has been well studied, offering insights into the advantages of sexual versus asexual reproduction. (3)

Intense competition between the various species has resulted in the increase in some populations and the displacement of some of the gecko species that have been resident for centuries. Most homes have two shifts, typically a day gecko visible around the house in the sunlight and another species during the night. The population around our house is typically Gold Dust Day Geckos by day and Mourning Geckos at night. I do not recall regularly seeing the Gold Dust last year, but this year they are more common.

There is very little negative about living with the geckos in the house. The biggest issue is that they do leave droppings, usually on windowsills and odd corners. Usually dry little things that vacuum up without issue. The loud barks do occasionally catch you by surprise, but soon become simply part of the experience of living with these little critters. You get used to hearing the little skittering claws, knowing that they are usually going after a meal, likely something you would rather not have in your house.

1) Our Little House Guardians, Linda Pascatore, Island Breath, 26 June 2008

2) Species data from GeckoWeb, retrieved 16 Nov 2008

3) Invasion and Competitive Displacement among House Geckos in the Tropical Pacific, Case, Bolger and Petran, Ecology, 1994, pp 464 to 477