Until now, birds got nearly all the credit for keeping organic coffee plantations where pesticides are banned insect-free, but a study from the University of Michigan has shown that during the summer wet season, bats eat more bugs than the birds at Finca Irlanda, a 740-acre organic coffee plantation in Chiapas, Mexico.
This is just one example of a great "ecological service" that went unnoticed until now. How many more do we benefit from without realizing it? Sadly, bat populations are declining worldwide, and the small flying mammals never got the love they deserve.
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-GuilleÌn 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.