Brazilian free-tailed bats (Tadarida brasiliensis) form enormous breeding colonies each summer in large caves in south-central Texas and northern Mexico. Prey of these bats includes several species of adult insects whose larvae are known to be important agricultural pests, including the corn earworm or bollworm (Helicoverpa zea). Authors estimate the value of the bats in controlling this pest in cotton production for an eight county region in south central Texas. and estimate the avoided damage at $741,000 per year, with a range of $121,000 to $1,725,000, compared to a $6 million per year annual cotton harvest.
