Crazy ants dominate fire ants by neutralizing their venom
Invasive “crazy ants” are rapidly displacing fire ants in areas across the southeastern US by secreting a compound that neutralizes fire ant venom, according to a new study. It’s the first known example of an insect with the ability to detoxify another insect’s venom.
Invasive “crazy ants” are rapidly displacing fire ants in areas across the southeastern U.S. by secreting a compound that neutralizes fire ant venom, according to a University of Texas at Austin study published this week in the journal Science Express. It’s the first known example of an insect with the ability to detoxify another insect’s venom.The crazy ant invasion is the latest in a series of ant invasions from the southern hemisphere and, like its predecessors, will likely have dramatic effects on the region’s ecosystems.Known for their painful stings on humans and other animals, fire ants dominate most ant species by dabbing them with powerful, usually fatal venom. A topical insecticide, the venom is two to three times as toxic as DDT on a per weight basis.When a crazy ant is smeared with the venom, however, it begins an elaborate detoxification procedure, described for the first time in this study. The exposed crazy ant secretes formic acid from a specialized gland at the tip of its abdomen, transfers it to its mouth and then smears it on its body.In lab experiments, exposed crazy ants that were allowed to detoxify themselves had a 98 percent survival rate. This chemical counter-weapon makes crazy ants nearly invincible in skirmishes with fire ants over food resources and nesting sites.”As this plays out, unless something new and different happens, crazy ants are going to displace fire ants from much of the southeastern U.S. and become the new ecologically dominant invasive ant species,” said Ed LeBrun, a research associate with the Texas invasive species research program at the Brackenridge Field Laboratory in UT Austin’s College of Natural Sciences.Last year, the researchers reported that where crazy ants take hold, the numbers and types of arthropods — insects, spiders, centipedes and crustaceans — decrease, which is likely to have ripple effects on ecosystems by reducing food sources for birds, reptiles and other animals. They also nest in people’s homes and damage electrical equipment.LeBrun described watching a battle for food between red fire ants and crazy ants along the boundary between their two populations at a Texas field site. The fire ants found a dead cricket first and were guarding it in large numbers. Usually when fire ants amass around a food resource, other ants stay clear for fear of their deadly venom.”The crazy ants charged into the fire ants, spraying venom,” said LeBrun. …
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