Informer: Geckos’ presence often leads to fewer pests
Last Modified: Friday, June 15, 2012 8:05 PM
By Andrew Perzo / American Press
The Informer recently heard from two readers who share a common interest — those chirping, translucent, nocturnal lizards that scamper about outside house lights and gaze down from porch ceilings.
“I was just wondering if anyone else has noticed that all the geckos that normally come out at night around the porch and garage lights are gone,” one reader wrote in an email.
“They were an introduced species anyway, Mediterranean geckos, I think. They are gone from my house, maybe from the mosquito spraying. Oh well. So be it.”
The second reader, who left a message on The Informer question line, had a less laissez-faire attitude and wondered whether the geckos could be responsible for ridding his property of another, more widely reviled pest.
“We live in an area where there are a lot of roaches. When we first moved here we had quite a few roaches in our house. But over the last four or five years I noticed that we had no roaches,” the reader said.
“It was about that time that I noticed geckos living around the perimeter of my house, and I was wondering if the presence of geckos has diminished the number of roaches?”
Question No. 1
Former McNeese faculty member Mark Paulissen, now a biology professor at Northeastern State University in Tahlequah, Okla., led a study of heavy metals accumulation in Southwest Louisiana geckos several years ago.
As part of that study, Paulissen wrote in an email, researchers “tried to look at gecko body condition (a statistic relating lizard weight and length) at sites that were in towns where nighttime mosquito spraying occurred versus sites in more rural areas where spraying does not occur.”
The data were limited, he said, but researchers found no difference between geckos in sprayed areas and those in unsprayed areas. Still, he said, geckos wouldn’t necessarily go unaffected by the spraying.
“I would suspect that the biggest effect of insect spraying would not be to the geckos directly (they don’t typically eat dead insects so probably wouldn’t ingest the chemicals) but it might reduce the number of insects they have available to eat,” Paulissen wrote.
“That might affect them over the long run, for example: Female geckos who weren’t able to get as much to eat may not be able to reproduce as often.”
Question No. 2
The Mediterranean gecko — its scientific name is Hemidactylus turcicus — feeds on a variety of creatures, including mites, ticks, spiders, snails, slugs, flies, ants, moths, beetles and roaches. A 1996 study of the stomach contents of 167 geckos found that roaches accounted for 1.2 percent of “prey items” found in the lizards’ guts.
“Wherever you have geckos, you have fewer roaches,” Paulissen wrote. “I noticed that at my house in Lake Charles, and it’s been widely reported from pretty much everywhere geckos inhabit human dwellings.”
A 2006 study of the gecko’s expansion in Louisiana — from four to 30 parishes in 17 years — noted the same thing: “Spiders, roaches, and crickets and, more specifically nocturnal wolf spiders and crab spiders, decline in the presence of H. turcicus,” researchers wrote in the journal Herpetological Conservation and Biology.
Incidentally, they noted that the gecko’s south-to-north dispersal in Texas ran along major highways and may have happened thanks to gecko eggs — with an average incubation period of 40 days — stowed away in boxes. They suggested the same thing likely happened in Louisiana.
The gecko, which arrived in the U.S. aboard cargo ships in the early 20th century, has since spread to isolated areas of the Gulf Coast and Southwest and, Paulissen said, even South Dakota.
Online: www.herpconbio.org.
The Informer answers questions from readers each Sunday, Monday and Wednesday. It is researched and written by Andrew Perzo, an American Press staff writer. To ask a question, call 494-4098, press 5 and leave voice mail, or email informer@americanpress.com
Posted By: Dwight On: 6/18/2012
Title: Geckos after Rita
We been in our house for 40 years. We never had Geckos under the carport until after Rita. At one time we would have 8 or 10 in the carport during warm nights. I've noticed very few the last couple of years. I still find some in the flower beds. They seem to like Confederate Jasmin.
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