Most scientists will never be able to easily explain their research to their next-door neighbors or father-in-law, let alone see their work reflected in public culture. But you never really know what can happen online. Recently, moth and bat-related memes have stormed the internet. Imagine my delight when my social media feeds were filled with clever representations of what I study: bat-moth interaction!
But: are these memes accurate? Yes, bats eat moths! Not all bats, of course; some eat fruit, or fish, or even other bats. But the majority of bat species primarily eat insects. Insect-eating bats will usually eat anything they find, if they can catch it. But as the memes suggest, many bats love to eat moths, and some greatly prefer them. For example, the bats I primarily study, Brazilian free-tailed bats, eat a wide variety of moth species!
How do we know this? Guano, or sparkly bat poop! For many years, biologists studied bat diet primarily by collecting guano pellets and then painstakingly teasing through each pellet under a microscope to find insect parts. There are book chapters devoted entirely to identifying insects by their legs and antennae, since they can survive passage through a bat’s digestive tract. But softer insects such as flies or moths don’t survive intact, so that approach is limited for moth species identification. Now we are lucky enough to have a new tool, molecular diet analysis. With this method, we grind up the insect DNA in the guano pellets and use powerful sequencing and computing processes to see exactly what the bats were eating. That’s how we can answer the question: do bats eat moths?
In my research, I found hundreds of different prey items eaten by free-tailed bats. More than 75% of those were moths! I was able to identify 130 of them to species, and at least 44 were agricultural pests. Thanks, bats! Other bat species also seem to prefer moths: the hoary bat, the European free-tailed bat, and the Rafinesque’s big-eared bat are some examples.
Sometimes, you can learn things from memes on the internet.