The Argentine ant Linepithema humile has become an invasive species causing significant damage to numerous habitats throughout most of the world. In many of the areas where this small invader has been introduced (also in Spain, see at the bottom of this news item) the native ants have disappeared and the pollination of various plants has been altered.
Australia is no exception. The tiny L. humile are displacing, and in some cases exterminating, the large native species, such as the meat ant, scientific name Iridomyrmex purpureus.
A team of researchers from the Commonwealth Scientific and Industrial Research Organization (CSIRO, Australia’s main public scientific research institution), has carried out a curious study in which they have applied mathematical models and virtual game tools (video games of the style of Age of Empires II) to imitate the confrontations between individuals and colonies of ants of various species in different habitats in Australia.
The results of this research, whose first signatory is Samuel J. Lymbery, professor at the Western Australia and Murdoch universities, have been published in the journal PNAS (published by the United States Academy of Sciences), indicating as the main conclusion that the best The way to avoid invasions such as those of the Argentine ant is to maintain the health (good state of conservation) of the ecosystems.
In other words, Argentine ants, despite being much smaller than Australian ants and reaching the island-continent in isolation, can be victors in group confrontations when they occur in altered or deteriorated habitats.
The results of the simulations have been confirmed with experiments with real ants, in laboratory confrontations supervised by the authors of the work now published.
“What we found in virtual games and then in real life ant battles was that mortality in small armies of Australian meat ants facing large armies of non-native Argentinean ants was lower in complex scenarios and higher in simple scenarios”, indicates Professor Lymbery in a somewhat more technical way in a note released by the CSIRO.
“So, just like in humans and in computer games, the outcome of ant wars depends on the nature of the battlefield.”
Raphael Didham, Professor of Ecology at the University of Western Australia’s School of Animal Biology and a CSIRO scientist, said social insects such as ants are among the species that engage in warfare on the same scale as humans.
“This is because the evolutionary future of the struggling sterile worker ants is invested in the greater good of the colony,” Professor Didham said.
In the work, “we used two ant species that clearly differed in their fighting prowess: the large Australian meat ant, Iridomyrmex purpureus, and the Argentine ant Linepithema humile, a species with small but highly aggressive and hypercooperative individuals.
Meat ants always beat Argentine ants in one-on-one duels due to their size advantage, but when the environment is altered, environmental conditions are simplified, natural resources disappear, and battlefields are created that favor species that fight in large groups such as the Argentine ant.
“This research suggests that modifying areas where native and non-native ants coexist, by adding natural features or other similar structures, may tip the balance in favor of our larger native species,” says Professor Lymbery.
