In Texas, a killer fungus solves a 20-year-old problem

Red crazy ants are a plague to Texas residents, but a parasitic fungus just might get the better of this invader.

The United States definitely have a lot to do on the side of the little beasts. In addition to the large Asian spiders that proliferate in the east of the country, we can also mention the red crazy ants. This invasive species, native to South America, has been making life difficult for the inhabitants of Texas for the past twenty years. But the population may see the end of the tunnel thanks to an unexpected ally: a killer fungus that loves these insects.

This is good news for the locals. Because since its arrival, this officially named species Paratrechina longicornis makes them see all the colors. Unlike Joro spiders, whose proliferation does not worry researchers, this ant tends to leave an indelible mark on the ecological niches it colonizes, even if it is not dangerous for humans.

A particularly invasive species

Research by the University of Texas has shown that they systematically chase all other species of ants from their territory. And it’s not just their cousins. Very many species of insects would have deserted these areas because of these ants, which wage a merciless war against them when it comes to appropriating the resources of the plants in the surroundings.

It’s some kind of horror movie”, explains Edward LeBrun, lead author of the study spotted by ScienceAlert. In fact, in some places like Estero Llano Grande Park, their arrival coincided with the local disappearance of many other species; we are talking about ants, but also about scorpions, lizards, snakes… Their presence would also have a significant impact on the nesting of certain species of birds.

They even attack much larger animal species. They can even attack livestock, large or small, in the eyes and nostrils. Some observers also consider them to be a potential plague for agriculture.

Even worse: they even cause considerable damage to infrastructure. They have the annoying habit of nesting in places like electrical circuit breakers, with all the consequences that implies.

A killer fungus to the rescue

For all these reasons, researchers are trying to force the red crazy ant to retreat, without success. But luckily for them, an unexpected ally might just do it for them; it is a pathogen similar to a killer fungus which is already wreaking havoc on these insects.

LeBrun’s team identified it in 2016, when they came across a few ants that looked surprisingly puffy. After analysis, the researchers found spores belonging to a completely new species of microsporidiumnever documented until now.

Very briefly, microsporidia are intracellular parasitic fungi; they are known for their propensity to turn insects into real Parasitic Trojans. Indeed, when they manage to lodge in a host, they transform certain cells into new spore production platforms which can in turn infect and then rapidly decimate the rest of the supercolonies formed by these ants.

A selective approach that can be used on a large scale

According to Edward LeBrun, lead author of the study, this pathogen has already contributed to the eradication of some populations of these ants. Together with his colleagues, they tried to exploit it to eradicate red crazy ants in a natural park by carefully controlling its spread. And the experience was a great success; in a few years, the park in question was completely purged of this invasive species.

The advantage is that this fungus is extremely difficult in choosing its hosts. This greatly limits its ability to ravage the entire ecosystem into which it is introduced; it is even possible to use it in such a way as to affect only that particular species. This represents a monumental ecological monitoring work, but the game is worth the effort.

The team will now test this pathogen in new sensitive ecological niches. They thus hope to protect the species threatened by the conquest of the Red Army within a few years.

The text of the study is available here.

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