According to an article from PhysOrg.com, researchers have found the ability of Argentine ants to change from carnivorous insect eaters to plant sap-loving creatures has helped these invasive social insects rapidly spread throughout coastal California, displacing many native insects and creating ant infestations familiar to most coastal residents.
Biologists at the University of California, San Diego and the University of Illinois at Urbana discovered the opportunistic, changing dietary preferences of California’s Argentine ants—the first time researchers have documented what these invasive ants actually eat—by studying a population of ants for eight years in the foothills southeast of San Diego. An advance copy of their paper is being published online this week in the journal Proceedings of the National Academy of Sciences.
“Despite the fact that these species are known to cause ecological problems in many countries, scientists really didn’t know what they eat,” said David Holway, an associate professor of biological sciences at UC San Diego who headed the study conducted in California and Argentina.
Holway, Edward LeBrun of UCSD, and Chadwick Tillberg and Andrew Suarez of Illinois discovered that when Argentine ants first move into an area they become fierce predators of native insects, feeding on the blood of native ants and other insects. But as the ants eliminate their competitors—and their main source of food—over time, they switch from a carnivorous, protein-rich diet to a largely carbohydrate, sugar-water diet as they begin feeding on the honeydew nectar from aphids and scales.