But why didn't we realize sooner that bats were doing the job? After all, we already know they're a good way to get rid of insects.

n previous experiments, the exclosures---simply net-covered wood-and-plastic frameworks---were placed over coffee bushes around-the-clock. After several days, scientists counted the insects on the protected plants and compared the tally to totals from nearby unprotected plants. The protected plants usually had higher pest counts, and birds generally received the credit.

But because the netting remained in place day and night, bats also had been excluded, Williams-Guillén said. And their impact went unnoticed.

So to examine each variable, a new experiment was devised where different types of nets were used at different times to exclude just birds, just bats, etc. Resulst: during the summer wet season, the bat-only exclosures resulted in an 84 percent increase in the density of insects, spiders, harvestmen and mites---exceeding the impact of birds.

So the next time you are drinking shade-grown organic coffee, think of bats.

::One large organic shade-grown coffee, please -- with extra bats

See also: ::Eco-Tip: How to Get Rid of Insects? Bats!, ::Bat House Competition Winner Chosen, ::Like A Bat Outta Heaven

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