The Mexican Free Tailed Bat and Seasonal Changes
By: Raquel Zuniga
Bats migrate every year from Mexico to our local cave named the Bracken Cave and spend their summers helping farmers by eating pests that would otherwise feast on their crops. The Bracken Cave is the largest in the world with a peak population of about 40 million Mexican free tailed bats. It has been studied recently that these bats are migrating earlier than usual, which might be caused by global warming. There is another weekly article that goes into more detail about global warming affecting bats migration cycle that you can read at https://www.sticksandstonesrescue.org/news/2018/3/4/weekly-article-bats-new-migration-cycle-due-to-climate-change.
Since bats are migrating earlier than usual, they may not be able to find enough food for themselves and their young because the insects they eat might not have hatched or arrived yet. If food isn’t available for them, bat colonies may shrink, and crops could become vulnerable when the insects arrive. This could cause farmers and their consumers a hefty loss.
The Mexican free tailed bat eats 20 different moth species and more than 40 other agricultural pests. The corn earworm moth is a favorite of the Mexican free tailed bat which eats plants such as corn, soybean, potato, and pumpkin, which costs U.S. farmers millions of dollars a year in ruined crops. A 2011 study estimated that bats indirectly contribute about $23 billion to the U.S. economy by keeping agricultural pests at bay from crops.
Another than dying from starvation, Joy O’Keefe, biology professor at Indiana State University, says, “early arrival at [the bats] summer roosts could expose these bats to cold snaps and they could freeze to death.” Another factor that bats could face is rainfall patterns. Many insects that bats eat breed in seasonal lakes and puddles. O’Keefe says, “If the bats arrive too early to benefit from summer rainfall and the resulting abundance of bugs, they may struggle to feed their pups or skip reproduction altogether.” She fears this shift could cause Midwestern bat population to decline towards extinction.
Read more about bat migration cycle and how they affect crop growth at: https://www.scientificamerican.com/article/bats-are-migrating-earlier-and-it-could-wreak-havoc-on-farming/ and https://www.popsci.com/climate-change-bat-migration.