An invasive ant species, the shiny-headed ant, is disrupting the lives of lions and zebras in Kenya

The arrival of an invasive ant species, the shiny-headed ant, has had disastrous consequences for elephants, lions, zebras and buffalo in Kenya. A group of international scientists discovered this.

In their study published in the scientific journal SciencesThey closely monitored – through observations and x-rays of animals – the effects of the arrival of a strange species of ant, the shiny-headed ant (Pheidol megacephala) in a Kenyan nature reserve.

The ants prey on local ant species that live in acacia trees. African acacia trees are known for their ability to defend against herbivores. Toxic tannins found in the leaves and spines on its branches make the species unattractive to herbivores.

But it also owes its protection to some aggressive ant species that live in symbiosis with the tree. The ants live in the swollen thorns, and in exchange for shelter they spray corrosive formic acid on herbivores that attack the tree.

Almost annoyed

This mutual cooperation, also called mutualism, seems to have been severely disrupted by the invasive vanity of the brilliant. This completely wipes out native ant species. It's very bad for the acacia, because the newcomer lacks the tree-protecting properties of the native ant. Elephants benefit from this, but with disastrous consequences: in areas where species alien to acacias live, elephants destroy seven times as many acacias as in areas where native ants still protect the trees.

Lions are also affected by this: as landscapes become more open, they find fewer hiding places to chase their favorite prey, zebras. In areas where the native ants still live, the number of zebras killed was 2.87 times higher than in areas where the new ants live.

Scientists saw that lions then changed their hunting pattern: instead of zebras, they hunted African buffalo. While from 2003 to 2020 the percentage of zebras killed by lions decreased from 67 to 42 percent, the percentage of buffalo killed increased from 0 to 42 percent during the same period.

Chain reaction

The researchers believe their research provides a new perspective on the chain reaction that occurs in an ecosystem after a disturbance. This is supported by Janneke van der Lubbe, an ecologist and specialist in invasive alien species at Radboud University's Bargerveen Foundation. “Many correlations are known. We know that their numbers are declining, but it is often difficult to pinpoint the cause: dehydration, the use of toxins, or something entirely different. There is no doubt in this research: the chain reaction begins with the shiny head.”

According to van der Lubbe, the publication on Kenyan ants could contribute to raising awareness about invasive alien species appearing around the world. There are also mutualistic relationships between ants in the Netherlands. They work with burnt blue. The eggs of that butterfly (which are protected) contain a scent that ants recognize from their larvae. As a result, they take the eggs to their nest, where they are raised like cuckoo babies.

Van der Lubbe: “If these native ants are displaced by invasive species, this could have equally severe consequences for the butterfly.”