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What triggers cicadas to make noises in unison, then go silent periodically?
Guy Cox
Sydney, Australia
Male cicadas sing to attract mates, and the Australian greengrocer is reputedly the loudest of them all. The problem is that this also attracts birds, for whom a cicada would be a tasty meal. The insects have therefore evolved to all sing together. Any passing birds are confused and don’t know where to go, but a female cicada can still identify a nearby male. As for why they stop, I guess it is when a sufficient number are otherwise engaged! Once again, it…
