cover photo by climber David Wittstock
Bat biologists are familiar with the question, “what good are bats?” Bats are valuable because they boost our economy, contribute to the health of our environment, give us tequila and a host of fruits, control insect pests, and help cure disease.
Economics and benefits of insect control
Probably the most compelling reason to love bats is because they provide a free pest control service. In a typical evening a bat can consume 25% – 75% of its body mass in insects. An 8-g lactating female little brown bat (Myotis lucifugus) consumed 10 g of insects in 1 night. A maternity colony of 1,000,000 Mexican free-tailed bats (Tadarida brasiliensis) in Texas is estimated to eat 8.4 metric tons (more than 18,500 lbs) of insects per night. Now extrapolating this consumption of insects throughout North America over the course of year brings us to an astronomical volume of insect pests removed with the use of insecticides or other contaminants. The eye-popping statistic is that this insect control is estimated to save the cotton industry of Texas $740,000 per year and save the agricultural industry of the U.S. $23 billion annually!
Tequila, bananas, and mangos
Some bats specialize on pollinating and eating fruit of plants that humans like to eat (and drink). Bats pollinate or disperse seeds for over 1000 species of plants, including bananas, mangos, cashews, breadfruits, and balsa wood. The long-tongued Leptonycteris bats pollinate the agave plant, which is the source of commercial tequila. So, go toast a bat!
Insect control: minimizing disease outbreaks
We’ve talked about the economic value of insect control from bats, but what role do bats play in minimizing outbreaks of insect-borne diseases, such as West Nile Virus? Or what role do bats play in minimize damage to our forests and other ecosystems when pine bark beetles or spruce bud worms populations explode? It is difficult to quantify these benefits, but, undoubtedly, bats play a role in minimizing human heath and forest ecosystem damage.
Draculin: an anticoagulant for heart patients
The unique biology of the vampire bats is contributing to human health concerns. Because the vampire bats feed on blood, they need a method of keeping that blood from clotting as they lap it. There is a anticoagulant in their saliva called Draculin that does this for them. Draculin is now being explored as a medicine for stroke patients.
For more information, find:
- T. H. Kunz et al. 1995. Dietary energetics of the insectivorous Mexican free-tailed bat during pregnancy and lactation. Oecologia (volume 101, pages 407-415)
- C. J. Cleveland et al. 2006. Economic value of the pest control services provided by Brazilian free-tailed bats in south-central Texas. Frontiers in Ecology and Environment (volume 4, pages 238-243).
- T. H. Kunz et al. 2011. Ecosystem services provided by bats. Annals of New York Academy of Sciences (volume 1223, pages 1-38)
- J. G. Boyles et al. 2011. Economic importance of bats in agriculture. Science (volume 332, pages 41-42)
- M. Kasso and M. Balakrishnan. 2013. Ecological and economic importance of bats. ISRN Biodiversity (volume 2013, pages 1-9)