Lazy moths taste disgusting

December 16, 2019

You might think that prey would invariably flee in terror from a predator. But what if an animal was apathetic in the face of danger?

A new study in Frontiers in Ecology and Evolution investigates why some moths are more relaxed fliers in the face of bat attacks. The research reveals that less appetizing moths are more nonchalant when attacked by bats, whereas more palatable moths tend to employ evasive maneuvers.

The work demonstrates the complex risks and rewards of anti-predator strategies where mistakes invariably mean death, and may let scientists predict the evasive behaviors of rare or even extinct species.

Many prey animals have evolved defense mechanisms to evade and deter potential predators. In moths, these include chemical defenses that make them less appetizing, ultrasonic hearing to hear bats coming, and mid-flight evasive maneuvers -- such as swoops and dives -- that help them to escape.

However, researchers understand relatively little about how these factors are linked and how they vary between different species. Dr. Nicolas Dowdy of the Milwaukee Public Museum and Wake Forest University in the US, noticed unusual behavior in certain species of tiger moths, which seemed to be relatively relaxed when attacked by predatory bats.

Intrigued by this behavior, Dowdy and his colleagues set out to identify the factors that contribute to this apparent nonchalance. They hypothesized that nonchalant moths have evolved chemical defenses that made them unpalatable, meaning they have less motivation to evade bats than their more delicious moth counterparts.

Why not just evade the bats anyway? Well, there are risks and rewards for specific anti-predator strategies. For instance, performing panicked evasive maneuvers might help a moth avoid a bat, but it might also land it in a spider's web or away from a food source or mate (in addition to being pretty exhausting). Dowdy speculated that unappetizing moths may often take the lazier and potentially safer option by relying on their chemical defenses rather than roll the dice on an emergency flight.

To test his hypothesis, Dowdy and his colleagues collected five different species of tiger moths and then released them in an outdoor "flight arena" at night, where wild bats would frequently swoop in to feed. Using infrared cameras, the team monitored interactions between the bats and moths and recorded how often different species displayed evasive or nonchalant behavior during a bat attack. They also measured how palatable the moths were to the bats by observing if the bats consumed the moths or spat them out.

"Strikingly, we observed that moths with weak or no chemical defenses often dive away to escape bat attacks," explained Dowdy. "However, moths with more potent chemical defenses are more 'nonchalant', performing evasive maneuvers less often."

This correlation allowed the researchers to predict the evasive or nonchalant behavior of the moths based on their palatability. It may be possible that this relationship between palatability and nonchalance exists elsewhere in the animal kingdom but future studies are needed.

An exciting extension of this work may be reconstructing behaviors of rare or even extinct species. By measuring levels of unappetizing compounds in preserved animal specimens as an estimate of a species' palatability, it could be possible to deduce whether or not these extinct creatures would have actively evaded predators or been more casual in their defensive behaviors.

At least there's a silver lining for disgusting moths: being repulsive means that you can rest a little easier in the face of danger.
Notes to Editors

Please link to the original research article in your reporting:


Corresponding author: Dr. Nicolas Dowdy


Corresponding Author's Institution: Department of Biology, Wake Forest University, Winston-Salem, North Carolina, USA


This work was supported by a National Science Foundation grant to WEC (IOS 0951160) and an NSF PRFB grant (DBI-1811897) to NJD

Frontiers is an award-winning Open Science platform and leading Open Access scholarly publisher. Our mission is to make research results openly available to the world, thereby accelerating scientific and technological innovation, societal progress and economic growth. We empower scientists with innovative Open Science solutions that radically improve how science is published, evaluated and disseminated to researchers, innovators and the public. Access to research results and data is open, free and customized through Internet Technology, thereby enabling rapid solutions to the critical challenges we face as humanity. For more information, visit and follow @Frontiersin on Twitter.


Related Bats Articles from Brightsurf:

These masked singers are bats
Bats wear face masks, too. Bat researchers got lucky, observing wrinkle-faced bats in a lek, and copulating, for the first time.

Why do bats fly into walls?
Bats sometimes collide with large walls even though they detect these walls with their sonar system.

Vampire bats social distance when they get sick
A new paper in Behavioral Ecology finds that wild vampire bats that are sick spend less time near others from their community, which slows how quickly a disease will spread.

Why doesn't Ebola cause disease in bats, as it does in people?
A new study by researchers from The University of Texas Medical Branch at Galveston uncovered new information on why the Ebola virus can live within bats without causing them harm, while the same virus wreaks deadly havoc to people.

The genetic basis of bats' superpowers revealed
First six reference-quality bat genomes released and analysed

Bats offer clues to treating COVID-19
Bats carry many viruses, including COVID-19, without becoming ill. Biologists at the University of Rochester are studying the immune system of bats to find potential ways to ''mimic'' that system in humans.

A new social role for echolocation in bats that hunt together
To find prey in the dark, bats use echolocation. Some species, like Molossus molossus, may also search within hearing distance of their echolocating group members, sharing information about where food patches are located.

Coronaviruses and bats have been evolving together for millions of years
Scientists compared the different kinds of coronaviruses living in 36 bat species from the western Indian Ocean and nearby areas of Africa.

Bats depend on conspecifics when hunting above farmland
Common noctules -- one of the largest bat species native to Germany -- are searching for their fellows during their hunt for insects above farmland.

Tiny insects become 'visible' to bats when they swarm
Small insects that would normally be undetectable to bats using echolocation suddenly become detectable when they occur in large swarms.

Read More: Bats News and Bats Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to