Like glow-worms, which spend two years eating snails - same method as fireflies, and then a week when the females set themselves up to be visible for part of the evening and the males fly blundering about in the dark trying to find them. The males only glow faintly in two small spots when disturbed. The larvae ditto. If the female fails to get a male by the end of a week, she crawls off into the soil, lays all the unfertilised eggs and expires.