By Dr. Becker
Declines in U.S. populations of bees and butterflies make regular headlines, but bats, which are another, albeit lesser known, pollinator, are also threatened. Habitat loss and the spread of disease, including White-Nose Syndrome, are primary threats to bat populations.
The U.S. National Wildlife Health Center estimated that northeastern bat populations have declined by 80 percent.
“The true ecological consequences of large-scale population reductions currently underway among hibernating bats are unknown,” the Health Center explained,1 as many people underestimate the importance of bats to the environment.
Bats’ Pest-Control Services Save Farmers More Than $1 Billion
One of bats’ claims to fame, aside from pollination, is their voracious appetite for insects. A pregnant or nursing bat may eat her own body-weight worth of insects each night, and night-flying insects, including the corn earworm moth, are a favorite food.
The corn earworm moth (or more specifically, the moths’ larvae) cause major damage to U.S. corn crops. Researchers from Southern Illinois University (SIU) wanted to find out what happens when bats aren’t allowed to feed freely on the moths, so they built large outdoor enclosures over cornfields in Southern Illinois.2
The enclosures were covered in nets that let insects in but kept bats out. The corn grown within the enclosures had significantly more larvae-damaged kernels – by 56 percent – and less fungal damage.
The researchers noted that bats “suppress pest-associated fungal growth and mycotoxin in corn” as well as increased crop yield by 1.4 percent, which adds up to a difference of more than $3 an acre.
Overall, the study found that bats save farmers more than $1 billion worldwide – and that’s only for corn crops. The estimate also doesn’t factor in other benefits that bats provide, such as a reduction in pesticide use. Study author Josiah Maine told BBC News:3
“Bear in mind that this figure does not take into account for the impacts of bats on the fungal diseases we found in the corn, or the micro-toxins produced by those fungal species.
It also does not account for the reduced amount of pesticides used in fields, as bats could be providing an additional valuable service to agriculture by suppressing pest populations below the threshold where pesticides are necessary.”
Loss of Bats Could Cost North American Economy Up to $53 Billion
In 2011, University of Tennessee at Knoxville researchers also analyzed the economic importance of bats in agriculture. They noted that since 2006 more than 1 million bats had died from White-Nose Syndrome while “unprecedented numbers” had also been killed by wind turbines.4
Their estimate came to an even greater value of bats than the SIU study. It estimated the value of bats to the agriculture industry at nearly $23 billion per year, but explained the estimate could be as far ranging as $3.7 billion to $53 billion a year.5
Gary McCracken, head of the Department of Ecology and Evolutionary Biology at the University of Tennessee, Knoxville told Science Daily:6
"These estimates include the reduced costs of pesticide applications that are not needed to suppress the insects consumed by bats. However, they do not include the downstream impacts of pesticides on humans, domestic and wild animals and our environment.
Without bats, crop yields are affected. Pesticide applications go up. Even if our estimates were quartered, they clearly show how bats have enormous potential to influence the economics of agriculture and forestry."
Pollination Is Another Bat Benefits
While some bats provide pest control, nectar-feeding pats act as beneficial pollinators. Giant cacti and agave are just two types of plants that depend on bats for pollination, and in the tropics over 500 different types of tropical plants are pollinated by bats every year.
Examples of foods that are pollinated by bats include bananas, peaches, cloves, carob and agave (used to make tequila). This pollination occurs courtesy of a very long tongue. As explained by Bat Worlds:7
“Bats tend to like flowers that don’t give off strong scents or offer bright colors. This is the opposite of what attracts bees. These types of flowers that the bats like also seem to have lots of nectar offered in them.
Many experts believe that the birds and bees take the day shift and the bats take the night shift. Everything that we know about pollination in the day time occurs at night with the bats.
What about the birds that have long beaks to get the nectar from flowers? Bats don’t have that feature but they are able to pollinate. The process is one that involved a very long tongue.
When the bat isn’t using it, this tongue is rolled up in the body, underneath the rib cage. When they are using it they have complete control over such movements.”
Bats Are “the Farmers of the Tropics”
Fruit-eating bats are sometimes called the farmers of the tropics because they are incredibly efficient at dispersing seeds. They’re especially essential to regenerating clear-cut forests, which requires seeds to be dropped over large, open spaces – areas where birds are reluctant to fly.
Bats cover large distances while feeding at night and defecate while flying, which means the seeds in their feces are scattered across the vast open expanses of clear-cut rainforests. According to Bat Conservation International:8
“ … many of the bat-dispersed seeds are from hardy pioneer plants, the first to grow in the hot, dry conditions of clearings. As these plants grow, they provide the shelter that lets other, more delicate plants take root. Seeds dropped by bats can account for up to 95 percent of the first new growth.
The pioneer plants also offer cover and perches for birds and primates, so they can add still more, different seeds to the mix that can lead eventually to a renewed forest. Bats have been reported dispersing the seeds of avocado, dates, figs, and cashews -- among many others.”
Northern Long-Eared Bat Added to List of Threatened Species
The U.S. Fish and Wildlife Service recently listed the northern long-eared bat as a threatened species after million have died from White-Nose Syndrome. The new status will allow for greater protections to areas where the bats hibernate and live in the summer, including protections to maternity trees where bats have their pups.
Some environmentalists feel the measure does not go far enough and have suggested the species be listed as endangered instead.9 In many parts of the world, bats remain a misunderstood animal, often regarded as diseased or dangerous.
In reality, bats are beneficial mammals that contribute greatly to their surrounding ecosystems, and they deserve respect to go along with it. If you’d like to do your part to help save bat populations in your area, try the following steps:10
- Avoid caves and mines where bats are hibernating during winter.
- Encourage natural bat habitats around your home by reducing outdoor lighting, minimizing tree clearing, and protecting streams and wetlands. Install a bat house.
- Adhere to cave closures. Check with your state and federal agencies or a local chapter of the National Speleological Society for the status of caves and caving in your area. Follow the national WNS Decontamination Protocol to clean and disinfect clothes, footwear, and equipment used in caves or mines.
- Talk to your family and friends about the benefits of bats and the fact that white-nose syndrome is decimating entire populations of bats across North America.
- Report unusual bat behavior, such as bats flying during the daytime in late-winter months, or bat deaths, to your state wildlife agency.