Believe it or not, from 1960 until the mid-1990s, the Sigma Chemical Company (now called Sigma-Aldrich) harvested about 3 million wild fireflies every year. Each summer, they ran newspaper ads to recruit thousands of collectors across the U.S., who got paid a penny per firefly (with a $20 bonus if they sent in more than 200,000 fireflies).

What did they do with all those fireflies?

They extracted firefly luciferase, the light-producing enzyme, then sold it for use in food safety testing and research.