An invasive species(入侵物种) of ant is changing the way lions hunt and eat in Kenya, according to a new study. Lions hide behind whistling thorn trees(哨刺金合欢) before they hunt zebras. However, since the big-headed ants arrived, the number of whistling thorn trees has fallen.
The big-headed ant is one of the world’s worst invasive species. This means it is not from the area. The ants arrived in Kenya from southern Africa about 15 years ago, and since then have been attacking the acacia ants—ants that have lived there long ago.
Acacia ants live in and look after the whistling thorn trees that spread over the landscape. In the “symbiotic relationship”(共生关系), the acacia ants feed on(以……为食) the trees and use them for cover. In return, they protect the trees from animals that might eat too much of them, like elephants or giraffes. They do this by moving and attacking together.
Big-headed ants eat acacia ants and their eggs. As a result, the number of acacia ants is falling. Big-headed ants don’t protect whistling thorn trees either, so with fewer acacia ants, the trees are in trouble.
Professor Todd Palmer, one of the study’s writers, and his team, found that in areas where big-headed ants appear, elephants destroy(破坏) five to seven times more trees than in areas without big-headed ants. This means the landscape is more open and zebras are better able to find any lion following them. Zebras that are killed in these areas are three times lower than in tree-filled places.
The good news is that the lion population remains stable(稳定的) because lions are looking elsewhere for their lunch—they seem to be hunting buffalo(水牛) instead of zebras. This probably means that the tiny ants have caused lions to change their behaviour too, forcing them to hunt in larger groups for the bigger, heavier buffalo. Professor Palmer said, “We often find it’s the little things that rule the world.”
(
B
) 1. The number of whistling thorn trees is becoming smaller mainly because
.
A. elephants need to eat more trees
B. big-headed ants don’t protect the trees
C. the trees are too old to survive
D. acacia ants don’t protect the trees
(
D
) 2. Which of the following best describes the “symbiotic relationship” between acacia ants and whistling thorn trees?
A. Both ants and trees attack elephants together.
B. The trees grow better when ants eat their eggs.
C. The ants eat the trees, and the trees provide shelter.
D. The trees feed the ants, and the ants protect the trees.
(
A
) 3. According to paragraphs 4 and 5, which shows the CORRECT order of the changes?
① The landscape is more open.
② The number of acacia ants is falling.
③ Whistling thorn trees are in trouble.
④ Fewer zebras are killed in this area.
A. ②③①④ B. ②③④① C. ③②①④ D. ③②④①
(
C
) 4. What’s the best title for the text?
A. The worst big-headed ant B. Changes of the whistling thorn trees
C. Tiny ants can change lions’ diets D. Acacia ants and big-headed ants
