Fort Myers, Florida (News-Press) -- U.S. Department of Agriculture scientists will be poking around for fire ants in Southwest Florida Wednesday, part of a study of the ant's population across the state.
The statewide study comes on the heels of anecdotal evidence that suggests the aggressive ant species may be decreasing in numbers.
Sanford Porter, research entomologist at the USDA Agricultural Research Service in Gainesville, said scientists will collect data on ants in Collier and Hendry counties today.
The sites to be checked were part of a study done 20 years ago, Porter said. There had been more sites then, he said, but many have been obliterated by roads that have been expanded.
"The situation is that we have seen things that make it look like there are changes in fire ant abundance," Porter said.
Porter said it was too early to make any sort of determination about the ant.
Locally, Porter said scientists would have been here sooner, but dry weather made collecting difficult.
"When it is dry, the ants don't build their nests high and you have to dig for them," he said, noting collection in the spring is "easier on us and easier on the ants."
Porter said scientists will spend the next few months gathering data, noting they want to find if any change is local or statewide.
The fire ant, which packs a wallop when it stings, has been a problem since it was accidentally brought to the U.S. between 1933 and 1945, according to records. The ants spread from Mobile, Ala., where they were first found, to almost every state in the South, from Texas to Maryland.
The ant swarms when its nest is disturbed; it has a painful sting that can cause allergic reactions in sensitive victims.
"We've had a lot of anecdotal reports and have ourselves noticed that the numbers are down," said Robert K. Vander Meer, a chemist and research leader for the Imported Fire Ant and Household Insects Unit at the USDA's Center for Medical, Agriculture and Veterinary Entomology in Gainesville. "But we haven't proved it scientifically."
Vander Meer said the study has produced information in Ocala. "We've seen some changes in population levels - much lower," he said.
He said as the study progresses scientists will check areas where data exists and then compare the information to see how things have changed.
Additionally, Vander Meer and Porter said there has been preliminary evidence showing an increase in colonies with one queen instead of multiple queens. Multiple queen colonies are an indicator ants are thriving, they said.
Possibly helping cut ant numbers, Vander Meer said, is an even smaller critter, the phorid fly.
He said several species of the fly, about 1/64 to 1/4 inches in length, have been released in Florida, including Southwest Florida, and other states starting in 1997, he said. Two of the species have spread out and colonized the state.
Phil Stansly, entomology professor at a University of Florida research center in Immokalee, said he was part of the release of the flies in Immokalee about 10 years ago. While Stansly said he has no evidence of the decline and isn't part of the study, he said scientists in Gainesville believe the flies are causing a decline in ant numbers.
The flies are known as decapitating flies. After a fly egg is laid in the ant's head and hatches, the ensuing larva will eat the ant's brain and eventually the ant's head falls off.
Vander Meer said the flies were evaluated before use to ensure they would not harm existing species.
"The flies are a great example of biological control," he said, noting more species of the fly will be released after further study.
Exterminators say ...
Locally, three pest control companies - one part of a large chain and two family-run operations - are split on the evidence about the ants' decline.
Lenny Volberg Sr. of Lenny's Pest Control in Cape Coral, said his company has been doing more work for fire ant control lately.
"Fire ants just don't go away," he said. "With the warm weather we've had lately, they'll be coming out soon."
But Terry McLaughlin of McLaughlin's Pest Control in Bonita Springs said he has noticed a decrease in fire ant activity.
"We have gotten fewer calls," he said. McLaughlin said he assumed the decrease was in response to new, more effective chemicals in use.
Bill McDole, a spokesman for Truly Nolen Pest Control in Fort Myers, said while he doesn't have evidence fire ant mounds are in decline here, there are better chemical controls now and fewer people are getting bit by the ant.
"There are new baits out there that allow the ants to bring them back to the nest to infect the queens," he said. He said it is pretty easy to kill fire ants. "All you have to do is pour hot water on them."