Image of the Day: Fire Alarm
Image of the Day: Fire Alarm

Image of the Day: Fire Alarm

Bats use both echolocation and vision to avoid eating unpleasant fireflies.

Sukanya Charuchandra
Aug 24, 2018

ABOVE: Firefly (Photinus pyralis)

Bats avoid fireflies based on their bioluminescence and movements, according to a study published August 22 in Science Advances. Previously, researchers thought fireflies used light only for the purposes of attracting mates.

Researchers forced interactions between the glowing insects and bats that were unaccustomed to the fireflies. The bats initially consumed the bugs, but over time they learned to avoid them. 

A bat first pursues a palatable scarab beetle (Callistethus marginatus) in flight, which it subsequently ingests. In the second interaction a bat captures then drops a firefly (Photinus pyralis). Finally, after several subsequent firefly interactions, a bat approaches and avoids another firefly.

After the researchers obscured the glowing bits of the fireflies with paint, the bats ate the insects, indicating that bioluminescence was a warning sign. In another experiment, the researchers found that bats did not avoid eating tethered and glowing fireflies to the same extent as they when the insects were free-flying, suggesting that movement was another deterrant. 

B.C. Leavell et al., “Fireflies thwart bat attack with multisensory warnings,” Sci Adv, doi:10.1126/sciadv.aat6601, 2018.