Close-up image of a tawny crazy ant. (Christine Sinatra via University of Texas at Austin)
Scientists believe an invasive species of ant that spews acid from its abdomen has finally met its match after discovering that a naturally occurring fungus is killing significant numbers of the ant species’ population.
The tawny crazy ant species has been ravaging the southeastern United States for 20 years, according to study authors from the University of Texas at Austin.
Native to South America, the tawny crazy ant first appeared in the United States in Florida in the early 1990s, according to Edward LeBrun, a researcher with the Texas Invasive Species Research Program at Brackenridge Field Laboratory and lead author of the study.
“Crazy ants, like all ants in this group, produce formic acid in the form of venom and use it as a weapon when fighting other ants,” the website continued.
The venom of the crazy ant is so strong that it can actually coat itself in its own venom as a form of protection against other ant species such as the fire ant. Although they are capable of biting humans, they are not poisonous, LeBrun told FOX television stations.
Since the early 2000s, the species has spread and taken up residence in residents’ circuit breakers, air conditioners, sewage pumps and other electrical appliances, causing short circuits and other damage, according to a press release on the study.
Introduced microsporidian pathogens
About eight years ago, scientists were studying crazy fawn ants in Florida when they discovered that a few had swollen abdomens. These ants were taken for observation and scientists found they were filled with fat, according to the press release.
Upon further investigation, it was discovered that the ants had “spores of a microsporidian, a group of fungal pathogens –a species new to science. Microsporidian pathogens typically hijack an insect’s fat cells and turn them into spore factories,” the press release continues.
Researchers still don’t know where this fungus came from but speculate that it may have come from the ants’ country of origin or perhaps it contracted it from another insect.
“I think it has a lot of potential for protecting sensitive habitats with endangered species or areas of high conservation value,” LeBrun said.
A total of 15 ant populations have been observed over the past eight years, the press release continues, and researchers have found that each colony infected with the fungus has seen its population decline. Sixty-two percent of these colonies have completely disappeared.
“You don’t expect a pathogen to drive a population to extinction,” LeBrun said. “An infected population normally goes through cycles of boom and bust as the frequency of infections rises and falls.”
Demographic control
Tawny crazy ant swarm insect. (Christine Sinatra via University of Texas at Austin)
For unknown reasons, scientists have found that the fungus does not harm native ant species or other arthropods, according to LeBrun.
In 2016, LeBrun and his research team received a call from Estero Llano Grande State Park in Weslaco, Texas asking for help in bringing the population of crazy ant species under control.
Park officials told LeBrun they were losing native species such as scorpions, lizards, snakes and even some birds.
“Baby rabbits were blinded in their nests by swarms of acid-spewing ants,” said a press release about the study.
“They had a crazy ant infestation, and it was apocalyptic, rivers of ants going up and down every tree,” LeBrun said. “I wasn’t really ready to start this as an experimental process, but it’s like, OK, let’s just try.”
The researchers used ants already infected with the fungus and inserted them into the invading colonies in the park and within two years the population had dwindled.
“Now they are non-existent and native species are returning to the area. Researchers have since eradicated a second crazy ant population at another site in the Convict Hill area of Austin,” the statement continued.
“That doesn’t mean crazy ants are going to go away,” LeBrun said. “It’s impossible to predict how long it will take for lightning to strike and the pathogen to infect a single population of crazy ants. But it’s a big relief because it means these populations seem to have a lifespan. .”
This story was reported in Los Angeles.