Killer fungus to replace deadly ants invading Texas

(ORDO NEWS) — When crazy ants make their way into new areas of Texas, these invasive species will wipe out local insects and lizards, chase away birds, and even blind rabbits by splashing acid in their eyes.

Scientists at the University of Texas at Austin have good news: A naturally occurring fungus-like pathogen can be used to reverse its rampant spread in the southeastern US, where it has been wreaking havoc for the past 20 years.

The results of the study were described Monday in the journal Proceedings of the National Academy of Sciences.

Ecologist and lead author Edward Lebrun told AFP that the fungus has already led to the extinction of certain species of invaders and will soon be tested in environmentally sensitive sites to protect endangered species.

Like the fire ants they have driven out in parts of Texas, the tinted crazy ants are native to Argentina and Brazil and made their way to the United States by ship.

They are called “crazy” because of their chaotic, jerky movements – in contrast to the orderly marches of their cousins.

Although they do not have the venomous sting of fire ants, they secrete formic acid which protects them from fire ant venom and incapacitates native animals.

“It’s kind of a horror show,” said Lebrun, who described the apocalyptic rivers of ants swarming the trees at an infestation he visited in Estero Llano Grande State Park, where native ants, insects, scorpions, snakes, lizards have died due to invaders. and birds.

Not only do they destroy ecosystems, “it’s a pity to live with them” for people, says Lebrun. The ants seek out electrical systems to build a nest by causing short circuits in circuit breakers, air conditioners and sewer pumps.

Pesticides are very toxic and only slow their progress, leading to the formation of snowdrifts of dead ants, which have to be removed, but the ants still break out.

About eight years ago, Lebrun and one of his co-authors, Rob Plows, were studying crazy ants they collected in Florida when they noticed that some of them had unusually large bellies, swollen with fat.

Looking inside their bodies, scientists found fungal spores of microsporidia – a type of fungal pathogen – and the species they found was completely new to science. Microsporidia usually take over insect fat cells, turning them into spore factories.

The origin of the pathogen is unclear – it may have come from South America, or possibly from another insect.

Whatever the case, the team found him appearing all over Texas. They followed 15 populations over eight years and found that every population the pathogen lived in declined, with 60 percent of the populations dying out completely.

As an experiment, the team decided to place infested ants with uninfested ants in a state park nesting site, placing hot dogs around the box’s exit chambers to lure the two groups into mingling.

Crazy ants form “supercolonies”, which means that individual groups do not fight each other for territory. This is a great advantage when exploring new territories, but it also turned out to be their biggest weakness, as it allowed the pathogen to spread uncontrollably.

The test was a huge success, and within a few years, the state park’s crazy ant population was reduced to zero. Particularly susceptible were larvae cared for by infected worker ants.

LeBrun explained that this is good news in two respects: First, the naturally occurring pathogen selectively affects invasive species, limiting their ability to destroy local ecosystems. Second, scientists can speed up the spread of the pathogen to wipe out the crazy ants faster.

However, he cautioned that the process is labor intensive and not one that could wipe out a species overnight. The team will continue testing their new biocontrol approach in sensitive habitats in Texas this spring.

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