Tiny ant species disrupt lion’s hunting behavior

In a study published in the journal ScienceA team of scientists reports that a tiny and seemingly harmless invasive ant species is changing the forest cover of an East African wildlife reserve, making it harder to hunt lions, the world’s most iconic predator, from their favorite prey, the zebra.

“These tiny invaders enigmatically tug at the threads that hold an African ecosystem together, determining who gets eaten where,” said Todd Palmer, an ecologist and professor in the biology department at the University of Florida.

The study, which spanned three decades of research, included a combination of hidden camera traps, collared lions tracked by satellites and statistical modeling. It illustrates the complex network of interactions between ants, trees, elephants, lions, zebras and buffaloes.

The disturbance begins in the acacia trees of the Ol Pejeta Nature Conservancy, an African wildlife reserve in central Kenya. Trees are historically protected from leaf-eating animals by a species of ant that nests in the trees’ bulbous thorns. In exchange for their home, ants fiercely defend trees against gigantic plant eaters, like elephants, giraffes and other herbivores – an arrangement that ecologists call mutualism.

In studies published in the early 2000s, Palmer began to unveil the complexities of this cozy East African relationship between plant and animal species.

“To our surprise, we discovered that these little ants served as incredibly powerful defenders and essentially stabilized the tree cover of these landscapes, allowing acacia trees to persist in a location with so many large herbivorous mammals.” Palmer said.

However, in the latest study, scientists say the arrival of an invasive insect known as the “big-headed” ant (Pheidole megacephala) sets off a chain of events that led to a change in predatory behavior – prey that could further endanger populations of lions, a species already on the verge of danger.

Big-headed ants are small but voracious insect hunters, destroying ant colonies that protect trees but not defending trees from larger animals. Having lost their bodyguards, the acacia trees are wiped out by the elephants.

Lions, which are ambush predators, rely on forest cover to stalk and hide before pouncing on zebras. Less forest cover means lions are not as successful at ambushing their prey.

“Often we find that it’s the little things that rule the world,” Palmer said. “These tiny invasive ants appeared maybe 15 years ago, and none of us noticed because they are not aggressive towards large creatures, including humans. We now see that they transform landscapes in a very subtle way but with devastating effects.”

Making the best of a bad situation, lions turn their attention to buffalo, Palmer said. However, buffalo are larger than zebras and hang out in groups, making them much more formidable prey.

“Nature is intelligent and creatures like lions tend to find solutions to the problems they face,” he said, “but we don’t yet know what might result from this profound shift in strategy. hunting lions. We are very interested in following this story.”

The field work in Kenya was led by Douglas Kamaru, a University of Wyoming doctoral student and Kenyan scientist. Palmer, Jake Goheen of the University of Wyoming, and Corinna Riginos of The Nature Conservancy were co-principal investigators. In addition to studying the phenomenon, researchers also say they are interested in finding solutions to stop the loss of tree cover in these emblematic landscapes.

“These ants are everywhere, especially in tropical and subtropical areas. You can find them in your yard in Florida, and people are the ones moving them around,” Palmer said. “We are working with land managers to study interventions, including temporary fencing of large herbivores, to minimize the impact of ant invaders on tree populations.”

As science continues to evolve toward highly advanced technologies such as AI-based data collection, Palmer said his group’s continued focus on Kenyan wildlife involved traditional methods over several decades, demonstrating the sustainability of field research.

“There are many new tools today involving big data approaches and artificial intelligence,” he said, “but this study was born from 30 years of driving Land Rovers in the mud.”