Informer: Mediterranean geckos hardy, hungry lizards

By By Andrew Perzo / American Press

Editor’s Note: Informer editor Andrew Perzo is on vacation. The following column originally ran in June.

The Informer recently heard from two readers who share a common interest — those chirping, translucent, nocturnal lizards that scamper about outdoor

wall 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.”

A side note: The Informer has found no shortage of geckos on the porches he frequents.

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 in his email. “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.

The gecko, which arrived in the United States 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.

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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