Tiny ants can change lions’ diets
An invasive species of ant is changing the way lions hunt and eat in Kenya, according to a new study. The species’ arrival has led to a fall in the number of whistling thorn trees, which lions hide behind as they sneak up on zebras.
The big-headed ant is one of the world’s worst invasive species. This means it is not originally from the area. The ants arrived in Kenya from southern Africa about 15 years ago, and since then have been attacking the native acacia ant.
Acacia ants live in and look after the whistling thorn trees that dot the landscape. In what’s known as a “symbiotic relationship” (meaning it benefits both sides) the acacia ants feed on the trees and use them for shelter. In return, they protect the trees from animals that might eat too much of them, like elephants, giraffes or rhinos. They do this by swarming and attacking. Big-headed ants are very aggressive and they eat acacia ants and their eggs. As a result, acacia ant numbers are falling. Big-headed ants don’t protect whistling thorn trees either, so with fewer ants to defend them, the trees are in trouble.
Professor Todd Palmer, one of the study’s authors, and his team, found that in areas where big-headed ants exist, elephants destroyed five to seven times more trees than in areas free from the invaders. This means the landscape is more open and zebras are better able to spot any lions stalking after them. Zebra kills in these areas were three times lower than in tree-filled places.
The good news is that the lion population remains stable because the big cats are looking elsewhere for their lunch – they appear to be hunting buffalo instead of zebras. This probably means that the tiny ants have caused lions to change their behaviour too, forcing them to hunt in larger packs for the bigger, heavier buffalo. Professor Palmer said, “We often find it’s the little things that rule the world”.