Bats provide valuable ecosystem services to agricultural crops by pollinating plants such as agave1 and managing pest insects of cotton2. For example, Brazilian free-tailed bats consume enough corn earworm moths each summer to delay the first pesticide application2. These bats’ economic value has been estimated at $22.9 billion per year2. However, the role of bats as a biological control for pest insects in apple orchards has not been fully explored. This project entitled Detection of Tarnished Plantbugs, Apple Maggots, and Codling Moths in Bats’ Diet in Southern Michigan Apple Orchards will focus on analyzing the diet of 4 common bat species in southern Michigan apple orchards. I will determine if they are foraging on 3 common pest insects known to damage apple crops. Bats will be mist-netted in conventional and organic orchards to collect fecal samples. The fecal samples will be analyzed with a genetic technique to identify insects within the fecal sample. In addition, insect samples will be collected to monitor emergence periods. The purpose of analyzing diet is to determine if these bats are foraging on important apple pest insects. Diet results will be compared among orchard management types and bat species to show if the bats are foraging on the pest insects and in what proportion during the insects’ peak emergence periods. This project will emphasize the importance of bats to the agricultural system and provide alternative methods of pest control for farmers to implement into their practices. Furthermore, future implications include estimating the economic value of bats to farmers with regard to pesticide use and pest damage reduction. The outcome of this research is to provide farmers with the knowledge of bat diet and ecology so they may integrate bats as a natural, sustainable, and less expensive alternative to chemical pest control. Bats as a natural pest control method reduce health risks associated with pesticide use and provide an additional source of natural predation. The anticipated outcomes will be evaluated through two surveys each season and two years after to farmers about bat and pest insect abundance on their property and the amount of damage to crops. Participating farmers will also receive a bat house for their property to begin attracting bats to their orchards.
1S. Ducummon, paper presented at the Bat Conservation and Mining Forum, St. Louis, MO, 4-16 November 2000.
2J.G. Boyles et al., Economic importance of bats in agriculture. Science. 332, 6025 (2011).
Project objectives from proposal:
Farmers will gain a basic understanding of bat ecology and bat diet as it relates to their orchard. Farmers will learn whether bats are foraging on any of the three target pest insects and if they increase predation of these insects during peak emergence periods. This will incentivize farmers in learning how to manage their properties for bats to take advantage of bats’ beneficial pest control properties. Participating farmers will receive a bat house to start attracting bats to their properties for future integration into their pest management program. Farmers who integrate bats may also reduce environmental harm over time with delayed or reduced pesticide applications each growing season.
Outcomes will be measured with surveys sent to farmers at the start and of growing season and for two years post-research. Surveys will include questions regarding an observed estimate of the bat population on their property increasing or decreasing, observed estimate of the pest insect populations on their property increasing or decreasing, and how well they feel bats have contributed to their orchard thus far. I will also ask about their economic gain or loss if bats increased on their property with pesticide applications and pest damage loss. Furthermore, a change in farmers’ behavior will be measured with the survey, addressing any modifications or additions they have made to their property to attract bats more.