forces the lion to change its hunting strategy

No one will say it but a small, big-headed ant is challenging the king of the jungle himself. This ant is a lion (Pheidole megacephala), a rampant invasive species that is altering the vegetation cover of the African Savanna, making it difficult for lions to hunt their favorite prey, the zebra.

Despite its harmless appearance, this ant is included in ranking Among the world’s 100 most harmful invasive alien species, A list prepared by the International Union for Conservation of Nature (IUCN). so this is it Put signature on By scientists who monitor the damage caused by the arrival of these feared species in areas where they did not previously exist, such as East Africa.

As ecologist Todd Palmer, professor of biology at the University of Florida and author of this research, recalls, about 15 years ago he began to explore the effects of the ant lion, known in English as the big-headed ant. , even though it had already happened. Has been colonizing new areas for some time. Field: “At first, none of us were aware of their presence They are not aggressive towards larger animals, including people. “Now we see that they are changing the landscape in very subtle ways but with devastating effects,” he warned.

The study appears this Thursday in the journal Science It is the result of three decades of observation of how complicated life is for Africa’s most emblematic predator, and is a good example of how complex and delicate the ecosystem is, as it is made up of ants, trees, lions, zebras, buffaloes. and reflects the network of interactions between elephants. , “These little invaders are pulling at the ties that hold African ecosystems together, and dictating who gets eaten and where,” says Palmer.

To conduct research, he combined observations on site With technologies like camera traps, collars to follow the steps of lions through satellite or statistical models. Thus, researchers found that lions have indirectly become less effective at killing their main prey, zebras, due to the invasion of big-headed ants in the Ol Pejeta Conservancy, a wildlife area located in central Kenya.

This is because these invasive insects kill off the native ants that protect the acacia leaves by preventing them from being eaten by elephants and other herbivores living in the area, a protective role that has been known since the beginning of the century : “To our surprise”, we discovered that Those little ants act as effective protectors of trees, Stabilize the tree cover of these landscapes and make it possible for acacias to survive in an area where large herbivorous mammals live,” says Palmer.

But that balance got disturbed with the arrival of the big headed ant. Without the protection of native ants, whose colonies are swallowed up by invasive species, There is no hindrance to elephants and other animals in eating the leaves of these trees, That gradually they become naked or semi-nude. With fewer trees to hide in, lions have difficulty ambushing zebras.

Lions, who are kings of the jungle for a reason, are adapting to the new situation and, according to Palmer, They are starting to pay more attention to African buffalo Difficulties faced in hunting zebras.

Thus, scientists determined that in locations that had not been reached by big-headed ants, zebra killing was 2.87 times higher than in locations that were invaded by this invasive species. From 2003 to 2020, the proportion of zebras killed by lions fell from 67% to 42%, while the proportion of buffalo killed increased from 0% to 42%.

So, the good news is that since the big-headed ant invasion was discovered, lion populations have not declined, at least for the time being, according to the authors.

“Nature is intelligent and creatures like lions find solutions to the problems they face, But we still don’t know what the consequences of this profound change in lions’ hunting strategy might be. We are very interested in following this story,” the ecologist admits.

The African savanna is not the only ecosystem the big-headed ant is changing, as according to Palmer, it has already spread to several locations: “He is everywhere, Especially in tropical and subtropical regions. “You can find them in your yard in Florida, and it’s people who move them from one place to another.”

The ant lion is a pest of some crops of coffee, cocoa and fruit trees, but is also used to control some pests that affect other crops or to control the expansion of some species of tick. which affect livestock.

According to Palmer, they are working with land managers to investigate interventions, including temporary fencing of large herbivores, to reduce the impact of invasive ants on tree populations.