Researchers have discovered a species of invasive ants triggering a chain reaction threatening lions as they lose their hiding spots for ambushing prey.
In a study published in the journal Science, a group of scientists found a small and seemingly harmless invasive ant species altering the tree canopy in the East African wilderness, making it difficult for lions, the world’s most renowned predators, to hunt their preferred prey, wildebeests, Phys.org reported on January 25th. ‘This tiny invader is pulling apart the ecological fabric that ties African ecosystems together, determining which species get eaten and where,’ said Todd Palmer, an ecologist and professor in the Department of Biology at the University of Florida.
A study spanning over three decades, combining hidden camera traps, satellite-tracked collars for lions, and statistical modeling, has revealed a complex network of interactions among ants, trees, elephants, lions, wildebeests, and buffalo. The disruption starts with the acacia trees in the Ol Pejeta Conservancy in central Kenya. These trees are protected from leaf-eating animals by a species of ants that nest in the bulbous thorns of the tree. In return for shelter, the diligent ant colonies actively defend the trees against elephants, giraffes, and other herbivores. This symbiotic relationship is what ecologists call mutualism.
In the early 2000s, Palmer began investigating the intricate mutualistic relationships between plants and animals in East Africa. He and his colleagues observed that small ants played a powerful role in providing robust protection, stabilizing the tree canopy in the region, allowing acacia trees to survive in areas densely populated with large grass-eating mammals.
However, in the latest study, scientists discovered the presence of an invasive insect known as the big-headed ant (Pheidole megacephala) triggering a cascading effect, leading to changes in the behavior between predators and prey, potentially endangering lion populations at risk of extinction. The big-headed ants are tiny but formidable insect hunters, destroying the ant colonies that protect the trees, yet not deterring large herbivores from eating leaves. Due to the loss of ant guards, elephants strip the leaves from the acacia trees.
Lions, ambush predators, rely on the tree canopy for concealment and stalking prey before pouncing on wildebeests. Fewer tree canopies mean lions have a more challenging time ambushing prey successfully. Lions shift their attention to buffalo. However, buffaloes are larger than wildebeests and gather in herds, making them much more formidable prey.
The on-site research in Kenya was conducted by a scientist and Ph.D. candidate at the University of Wyoming, alongside Kenyan scientist Douglas Kamaru. Palmer, along with Jake Goheen from the University of Wyoming and Corinna Riginos from The Nature Conservancy, is a co-author of the study. In addition to understanding the phenomenon, the expert team indicates their intention to find solutions to prevent the decline of tree canopies in East Africa.
