Hovering in the air like tiny golden orbs isn't enough for some fireflies. A handful of species behave more like strobe lights that can light up a forest when they flash in unison. For decades scientists didn't know why some fireflies glow in synch. Now researchers may have the answer: It's a major turn on for girls. In a paper  that will be published tomorrow in Science, researchers tested the idea on female fireflies from the Great Smoky Mountains, a mountain range along the Tennessee-North Carolina border. Using green LEDs, they mimicked the flashing of male fireflies, with patterns ranging from perfectly in synch to almost entirely out of phase. More than 80% of the females double-flashed in response to the synchronized LEDs, while they all but ignored the out-of-synch signals. The authors speculate that the synchronized blinks might help females recognize other males of the same species by their specific flash patterns. The delay between flashes could also give the females a chance to get a word in, flashwise, without being drowned out by the males.
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