Tiger moths: Mother Nature's fortune tellers

Jun 03, 2013

When it comes to saving its own hide, the tiger moth can predict the future. A new study by researchers at Wake Forest University shows Bertholdia trigona, a species of tiger moth found in the Arizona desert, can tell if an echo-locating bat is going to attack it well before the predator swoops in for the kill – making the intuitive, tiny-winged insect a master of self-preservation.

Predators in the night

A bat uses sonar to hunt at night. The small emits a series of ultrasonic cries and listens carefully to the echoes that return. By determining how long it takes the sound to bounce back, the bat can figure out how far away its prey is.

Aaron Corcoran and William Conner of Wake Forest previously discovered Bertholdia trigona defends itself by jamming its predators' sonar. Conner, a professor of biology, said the tiger has a blister of cuticle on either side of its thorax called a tymbal. It flexes this structure to create a high-pitched, clicking sound.

The moth emits more than 4,500 clicks per second right when the bat would normally attack, jamming its sonar.

"It is the only animal in the world we know of that can jam its predator's sonar," Conner said. "Bats and tiger moths are in the midst of an evolutionary arms race."

The new study published May 6 in the journal PLOS ONE, shows that tiger moths can tell when it is time to start clicking by listening for a telltale change in the repetition rate of the bat's cries and an increase in sound intensity. The combination of these two factors tells the moth that it has been targeted.

Conner's team used high-speed to create of the flight paths of bats attacking tiger moths. They then used an ultrasonic microphone to measure the rate of bat cries and moth clicks.

Normally, a bat attack starts with relatively intermittent cries. As it gets closer to the moth, a bat increases the rate at which it produces cries —painting a clearer picture of the moth's location.

Conner's team found that soon after the bats detected and targeted their prey, moths increased their rate of clicking dramatically, causing the predators to veer off course. The sonar jamming works 93 percent of the time. When the tymbal is removed, Conner says the bat will catch the tiger moth 83 percent of the time.

He said this is the first quantitative study to show an animal can trigger defensive behaviors by measuring ultrasonic signals provided by predators during an attack.

Explore further: New England Aquarium offering penguins 'honeymoon suites'

Related Stories

Moth ears are activated by movement the size of an atom

Oct 20, 2011

(PhysOrg.com) -- Moths are so finely tuned to the ultrasonic calls of predatory bats that the nerve cells in their ears are activated by displacements of the eardrum the size of a small atom, according to ...

New website calls for help from bat detectives

Oct 03, 2012

Scientists are asking for the public's help to monitor bats across Europe and track changes in our environment by listening to their weirdly wonderful ultrasonic tweets on a new website.

Recommended for you

Telling the time of day by color

Apr 17, 2015

Research by scientists at The University of Manchester has revealed that the colour of light has a major impact on how the brain clock measures time of day and on how the animals' physiology and behavior adjust accordingly. ...

Aphrodisiac for fish and frogs discovered

Apr 17, 2015

A supplement simply added to water has been shown to boost reproduction in nematodes (roundworms), molluscs, fish and frogs – and researchers believe it could work for humans too.

Evolution puts checks on virgin births

Apr 17, 2015

It seems unnatural that a species could survive without having sex. Yet over the ages, evolution has endowed females of certain species of amphibians, reptiles and fish with the ability to clone themselves, ...

Humans can't resist those puppy-dog eyes

Apr 16, 2015

When humans and their four-legged, furry best friends look into one another's eyes, there is biological evidence that their bond strengthens, researchers report.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.