Bats have a bad reputation. In reality, bats can be a farmer’s best friend by providing free and effective pest control services over farm fields and orchards.
Most bat species in the United States are generalist insect predators, which means they will consume most medium-sized flying insects. Determining exactly what insects bats eat is often difficult, since bats feed in the sky at night. Until recently, scientists studied the diet of bats by dissecting fecal pellets under a microscope and identifying insect fragments, such as pieces of exoskeletons or legs, that survived the digestive tract of the bat.
With the exception of hard-shelled insects, including some stinkbugs and beetles, this rarely allowed for identification of insects to species level. Scientists could confirm that bats ate moths but could not confirm that bats were consuming specific pests of economic interest.
Modern techniques in the field of genetics now allow scientists to recover DNA from fecal samples and identify the insect remains found in bat feces by sequencing the insects’ DNA. Using these modern techniques, bat researchers across the country have identified to species level almost 200 insects that are consumed by bats, and many of these insects cause substantial economic loss.
Most of the insects consumed in the United States are beetles and moths. While it is generally the larval form of moths that damage crops, bats are benefiting the crops by consuming the adult flying forms, therefore preventing the insects from further reproducing.