Argentine ants are taking over the world or at least the nice temperate parts. They've spread into Mediterranean and subtropical climates across the globe in sugar shipments from Argentina, and no native ant species has been known to withstand their onslaught until now. A group of Stanford University undergraduate students working on a class project have discovered that a native species, the plucky winter ant, has been using chemical warfare to combat the Argentine tide.
The winter ants named for their unusual ability to function in cold weather, rather than grind to a halt like most insects manufacture a poison in a gland in their abdomen that they dispense when under extreme duress. One tiny drop applied to an Argentine ant is enough to put an end to it. In laboratory testing, the poison had a 79 percent kill rate.
"This is the first well-documented case where a native species is successfully resisting the Argentine ant," said Deborah M. Gordon, a biology professor at Stanford who specializes in studying ants and taught the three-week summer class in which the students first saw the winter ants wielding their poison.
"I did not believe it at first," she said. "This is a group of ants that does not have a sting and you don't see them acting aggressively, but the students were able to show very clearly not just that the winter ants are using poison, but when they use it, how they use it and what the impact is."
Gordon and her students presented their findings in a paper published earlier this year in PLoS ONE, a journal published by the Public Library of Science.
The Argentine ants are happy anyplace that has cool, rainy winters and hot, dry summers. They have conquered the entire coastline around the Mediterranean Sea, parts of South Africa, Hawaii, Japan and Australia, as well as the full length of the California coastline.
"If you live in a Mediterranean climate, the Argentine ant is the a
|Contact: Louis Bergeron|