Infectious Fungus Wreaks Havoc on Crazy Ants—and Scientists Are Thrilled

Invasive tawny loopy ants are spreading wildly within the southern United States, however these problematic bugs appear to have met their match within the type of a extremely infectious fungal pathogen. Scientists at the moment are utilizing this naturally occurring fungus to fight loopy ant populations, with stunning success.

New research in Proceedings of the National Academy of Sciences is claiming that the microsporidian pathogen Myrmecomorba nylanderiae is a secure, efficient, and pure means to curb the unfold of loopy ants. In a University of Texas at Austin press release, Edward LeBrun, the lead writer of the research and a researcher with the Texas Invasive Species Research Program at Brackenridge Field Laboratory, mentioned the fungal pathogen holds “a lot of potential for the protection of sensitive habitats with endangered species or areas of high conservation value.”

Native to South America, the tawny loopy ant (Nylanderia fulva) has been spreading by the southern U.S. states of Texas, Mississippi, Florida, and Louisiana for the higher a part of twenty years. The ants are disruptive to populations of bugs, spiders, centipedes, crustaceans, and even the odd mammal; the ants are identified to blind child rabbits by oozing an acid into their eyes. They’re an ecological menace, however additionally a risk to human infrastructure. Crazy ants are notorious for swarming and damaging air-con models and different electrical equipment.

Frustratingly, tawny loopy ants don’t respond to standard pesticides, making them tough to handle. Write the scientists of their research: “Invasive social insects are among the most damaging of invasive organisms and have proved universally intractable to biological control.”

But it was round eight years in the past that LeBrun started to note one thing uncommon: A stunning variety of tawny loopy ants have been found to have enlarged abdomens swollen with fats. Looking into this additional, he and his colleagues recognized the trigger as spores from a bunch of fungal pathogens referred to as microsporidians. This infectious fungus hijacks the fats cells of tawny loopy ants, turning them into veritable spore factories.

The supply of this mysterious pathogen just isn’t but identified. The ants may need introduced it from South America or contracted it from different bugs. Regardless, the scientists started to note these infections throughout a lot of Texas, prompting a multi-year research to analyze additional. From 2012 to 2018, the staff repeatedly sampled 15 native populations of tawny loopy ant within the state. As they realized, the consequences of M. nylanderiae are devastating, to say the least. Every web site surveyed suffered dramatic declines in inhabitants, and 62% have been merely erased.

That’s intense—infectious pathogens aren’t normally this brutal. Normally, contaminated populations go “through boom-and-bust cycles as the frequency of infection waxes and wanes,” mentioned LeBrun. In phrases of an evidence, the declines in native populations “occurred primarily over the winter,” because the scientists wrote of their research. “Perhaps population collapse arises because the lifespan of the infected worker population is insufficient to bridge the gap in winter brood production,” they wrote, including that the “decline of colony fragments in the laboratory supports this hypothesis.”

Importantly, the fungus appears unique to tawny loopy ants and doesn’t appear to have an effect on different ants or arthropods. It’s for that cause that LeBrun and his colleagues are hoping to make use of the fungus as a focused biocontrol agent. The staff examined this precise factor in 2016 at Estero Llano Grande State Park in Weslaco, Texas, which had been overrun by the ants. “They had a crazy ant infestation, and it was apocalyptic, rivers of ants going up and down every tree,” LeBrun defined within the college launch. “I wasn’t really ready to start this as an experimental process, but it’s like, okay, let’s just give it a go.”

For the experiment, the scientists collected loopy ants contaminated with M. nylanderiae and introduced them to Estero. Like ticking time bombs, the contaminated ants have been dropped at nesting websites within the state park. Hot canine have been used to lure uninfected native ants, facilitating the merger of the 2 populations. The outcomes have been profound, with the fungal pathogen finally spreading throughout all the loopy ant inhabitants within the state park. The variety of loopy ants dropped to virtually nothing after two years, and native species at the moment are returning to Estero. “In contrast, uninfected populations [of crazy ant] showed no tendency to decline over a similar period,” in accordance with the paper.

The scientists repeated this experiment at an space close to Convict Hill in Austin, and with the identical outcomes. At each websites, “average disease burden of infected nests increased exponentially throughout the period of pathogen spread and N. fulva population decline,” and loopy ant “populations declined to local extinction following widespread pathogen establishment,” the paper mentioned.

More experiments are deliberate for later this yr at different Texas areas, in what’s a really encouraging improvement. It virtually appears too good to be true—a pure biocontrol agent that doesn’t appear to be dangerous outdoors of its impact on loopy ants. Hopefully the outcomes will proceed to be optimistic and that conservationists will lastly have an efficient software at their disposal to fight these extremely problematic ants.