2007-06-21 18:33:53 · 4 answers · asked by EMU B 1 in Science & Mathematics ➔ Zoology
Most cicadas go through a life cycle that lasts from two to five years. Some species have much longer life cycles, e.g. the Magicicada goes through a 17- or occasionally 13-year life cycle. These long life cycles are an adaptation to predators such as the cicada killer wasp and praying mantis, as a predator could not regularly fall into synchrony with the cicadas. Both 13 and 17 are prime numbers, so while a cicada with a 15-year life cycle could be preyed upon by a predator with a 3- or 5-year life cycle, the 13- and 17-year cycles allow them to stop the predators falling into step.
2007-06-21 18:40:02 · answer #1 · answered by joe k 2 · 1⤊ 1⤋
They come out only to produce .-Cicadas have spent the last 16 years under ground feeding on tree roots – on the 17 year they emerge to sing, mate and lay eggs.
2007-06-21 18:43:22 · answer #2 · answered by nenamexicana 2 · 0⤊ 0⤋
Not all come out every 17 years. Do your research, you will find a different answer.
2007-06-25 17:07:44 · answer #3 · answered by Banker 6 · 0⤊ 0⤋
That's just their way. Nobody really knows. There are only hypothesis. The one I heard was that predators will have fewer opportunities to eat/kill them if they emerge only once every 17 years to mate.
UPDATE: Thumbs down to Joe K for plagiarism... his source pasted below.
2007-06-21 18:37:21 · answer #4 · answered by Mickey Mouse Spears 7 · 0⤊ 0⤋