what do most bats eat?

best answer
There are at least 40 different kinds of bats in the U.S. that eat nothing but insects. A single little brown bat which has a body no bigger than an adult human’s thumb can eat 4 to 8 grams (the weight of about a grape or two) of insects each night. Although this may not sound like much it adds up—the loss of the one million bats in the Northeast has probably resulted in between 660 and 1320 metric tons of insects no longer being eaten each year by bats.