No Picky Eaters Among Successful Argentine Ants

The Argentine ant is a very successful invasive species, having conquered territories far from its native South America. Once introduced, inadvertently, by people, it marches across the landscape, displacing local ant species and making an agricultural pest of itself.

Researchers from the University of Illinois and the University of California at San Diego have uncovered one secret to the ant’s success: dietary flexibility. The insects can live high on the hog, but will eat at lower levels of the food chain if they have to.

Chadwick V. Tillberg and colleagues studied an invasion of ants across a canyon in Chula Vista, Calif., over eight years. They collected ants at various sites and analyzed the ratio of stable nitrogen isotopes in the insects, an indication of what they were eating.

As the researchers report in The Proceedings of the National Academy of Sciences, ants right at the invasion front showed higher levels of nitrogen-15, suggesting they were consuming native ants and other insects. But as the front moved on, nitrogen-15 levels declined, with the ants switching to food from plants, particularly the honeydew produced by aphids.

Read the full New York Times story here.