Scientists have discovered that male fireflies in a South Carolina swamp follow local interaction rules to synchronize their flashing mating displays. The research is being presented at a meeting of the American Physical Society in Denver. (A preprint is also available on the biorxiv.) Such work could one day lead to insights into how the body's cells sync to its internal circadian rhythm, or how neurons fire together in the brain, as well as the design of drone swarms communicating through synchronized flashes. As previously reported, research into swarming and flocking was largely relegated to observational biologists for decades. But in the 1980s, a computer graphics specialist named Craig Reynolds developed the so-called “boids” program, an agent-based computational model that has dominated collective behavior studies ever since. In such a model, each individual unit in a swarm is a dot moving in a straight line at a constant speed.…