Fireflies used rapid light flashes to communicate.
This 'bioluminescence' is an intriguing phenomenon that has many potential applications, from drug testing and monitoring water contamination, and even lighting up streets using glow-in-dark trees and plants.
Fireflies emit light when a compound called luciferin breaks down.
We know that this reaction needs oxygen, but what we don't know is how fireflies actually supply oxygen to their light-emitting cells.
Using state-of-the-art imaging techniques, scientists from Switzerland and Taiwan have determined how fireflies control oxygen distribution to light up their cells.