Birds protect trees by eating insects

Washington, April 8 (ANI): Birds, bats and lizards protect trees by reducing the numbers of leaf-eating insects, a new research has found.

"Our findings are relevant to natural communities like grasslands and forests, but also to human food production, as these insect-eating animals also reduce insect pests on crop plants," said Sunshine Van Bael, scientist at the Smithsonian Tropical Research Institute.

Previous theory on food webs suggested that the effects of insect-eaters on plants would be weak, because animals like birds not only feed on herbivores - which is good for the plants- but may also benefit them by feeding spiders and predatory insects.

For example, if a bird eats a lot of spiders, caterpillars could be "released" from spider predation and then consume more plant material.

The authors found that previous theory did not hold true; in fact, the birds simply ate the spiders and the caterpillars.

The authors reviewed more than 100 studies of insect predation by birds, bats or lizards from four continents. They found that the identity of the predator didn"t make much of a difference.

Together, by eating herbivores and their insect predators, they reduced damage to plants by 40 percent, which resulted in a 14 percent increase in plant biomass.

"Our study shows that birds, bats and lizards act as one big vacuum cleaner up in the treetops," said Van Bael.

Lead author Kailen Mooney, professor of ecology and evolutionary biology at the University of California-Irvine, said: "Our study shows that birds, bats and lizards protect plants, underscoring the importance of conservation of these species in the face of global change.

The study has been published online by the prestigious journal, Proceedings of the National Academy of Sciences. (ANI)