The Winter Ant Poisons Its Enemies With Toxin Secreted From Its Abdomen
Posted on August 14, 2011
Chemical warfare exists in the ant world. Stanford University undergraduate students discovered that the winter ant can secret a deadly whitish toxin on its enemies. In the photograph above, the winter ant is secreting the poison from its abdomen onto an Argentine ant. The angle of the photograph distorts the relative sizes of the two species. The ants are actually about the same size.
The Stanford students found that the winter ants are using the toxin to fight off the aggressive Argentine ants, which have been spreading around the globe and are considered pests. The poison is very effective. The researchers say one tiny drop of toxin applied to an Argentine ant is enough to kill 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. "I did not believe it at first. 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."
The Stanford students began observing the native ants as part of a class called Ecology of Invasions, which is taught by Professor Gordon. The students started out simply observing and recording ant behavior while visiting sites on the Stanford campus at the same time every day.
Leah Kuritzky, a student in the class and one of the coauthors of the paper, said, "We were looking at the nest openings of the winter ants and one day it was just winter ants going about their business foraging for food and making trails - just typical ant behavior. The next day we came back and the ground was littered with Argentine ants. There were dead ants all around and there was a lot of fighting around the nest entrances."
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.