Birds get the credit, but bats eat more bugs

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - Bats play a bigger role than birds do in controlling tropical insects, and the loss of bats might mean that morning cup of coffee gets more expensive, researchers said on Thursday.

Two separate studies show bats eat far more insects than birds do, protecting plants of the rain forest and, in one of the studies, coffee plantations.

The studies, published in the journal Science, suggest that the loss of bat populations worldwide might affect agriculture -- not to mention make warm evenings outside more uncomfortable, the researchers said.

"Bats are impacting ecological systems in all kinds of ways, and I just want them to get the credit they deserve," said Kimberly Williams-Guillen, a tropical ecologist at the University of Michigan who led one of the studies.

Williams-Guillen and colleagues studied bats at Finca Irlanda, a 740-acre (300-hectare) organic coffee plantation in Chiapas, Mexico.

In previous studies of insect damage, scientists have simply covered plants to keep off birds and then counted the bugs and measured what they ate. They forgot to account for what the bats did at night.

Williams-Guillen and her colleagues set up three types of enclosures -- one that only excluded birds, one that only excluded bats at night, and nets that kept out birds and bats day and night.

During the summer wet season, the coffee trees under the nets that kept the bats out had 84 percent more insects, spiders and other bugs than unprotected plants, they reported.