Fireflies glow to both attract mates and also to keep away predators. But new findings show that the bioluminescence in adult fireflies came about much before the evolution of flying predators that the lights today keep away. ThePrint’s Sandhya Ramesh explains findings from a new pre-print.   Supplementary reading: Firefly bioluminescence outshines aerial predators https://www.biorxiv.org/content/10.1101/2021.11.22.469605v1.full.pdf