Invasive Ants Could Be Beaten Back With a Targeted Virus

The idea is sound, but work needs to be done to ensure the virus doesn’t take out other insects as well

Argentine ants
Argentine ants George D. Lepp/Corbis

Invasive ants just aren’t good news. They invade homes, deform seabird chicks in Hawaii and outcompete local ants for food and space. So far, only other invasive ants seem to stop some species — but that’s simply trading one problem for another. But now there's some potentially good news on the invasive ant front: Researchers may have discovered a way to combat invasive ant species and the solution just might help honeybees as well.

For Science, David Shultz reports that scientists have found a virus that infects the aggressive invasive species called Argentine ants. This species, originally from Argentina, has spread to every continent except Antarctica, thanks to its tendency to form 'supercolonies.' Instead of single colonies competing against each other, Argentine ant workers move from one to the other.

The New Zealand-based team first noticed that sometimes these massive colonies of Argentine ants collapse and die for no obvious cause. The researchers wondered if the supercolony strategy somehow made the ants vulnerable to diseases. A pathogen that got into one nest wouldn’t just wipe out that colony, but potentially the whole supercolony. But they needed to find the smoking gun, the virus or bacteria or fungi infecting the ants.

After sequencing genetic material from two separate nesting sites, the team found several viral species that might be infecting the ants and identified a new virus they call Linepithema humile virus 1 (LHUV-1), Shultz reports. They wrote up their discoveries in Biology Letters. They also found a virus called deformed wing virus or DWV, which might play a role in honeybee population declines

Other viruses similar to LHUV-1 kill red fire ants, and the researchers hope that either this virus or another on could be used as biocontrol agents to wipe out Argentine ants. However, David Holway, an ecologist at the University of California, San Diego, isn’t sure this is the solution for bees or for ants, according to Shultz. He writes:

The ants could just as easily be picking up the virus from the bees during the same raids. As for whether the virus could be used to fight the ants, Holway points out that nobody has even determined whether the virus hurts them. “If there was some species-specific pathogen that knocked out the Argentine ant, I would be extremely happy,” he says. But he notes that pesticides could also be killing the ants, he and points out that whether or not the Argentine ant population is declining as a whole is still contentious.    

Still, the idea isn’t unfamiliar to scientists: Parasitic wasps are being using to fight the invasive emerald ash borer in Colorado and Minnesota. At this point, scientists just need to find what tool Nature uses to keep the ants in check.

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