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Periodical cicadas in eastern North America spend 13 or 17 years underground, then emerge together in their millions for a few weeks of song and mating.

Smithsonian / Purdue Extension

ScienceNature

The story behind the card

Periodical cicadas belong to the genus Magicicada. Their young, called nymphs, live underground and feed on sap from tree roots. All the cicadas of one generation in an area, known as a brood, surface within the same few weeks, sometimes several million on a single hectare. Birds and other predators soon eat their fill, so most cicadas survive long enough to mate, a strategy called predator satiation. The adults live only a few weeks. Both 13 and 17 are prime numbers, and one idea is that such cycles rarely line up with predators that breed on shorter cycles, or with neighbouring broods.

Türkçe oku
Kuzey Amerika'nın doğusundaki periyodik ağustosböcekleri 13 ya da 17 yıl toprağın altında yaşar; sonra milyonlarcası aynı anda yeryüzüne çıkar ve birkaç hafta boyunca öter, çiftleşir.

Periyodik ağustosböcekleri Magicicada cinsindendir. Nimf denen yavruları toprağın altında yaşar ve ağaç köklerinin özsuyuyla beslenir. Bir bölgede aynı kuşaktan bütün böcekler birkaç hafta içinde birlikte yeryüzüne çıkar; tek bir hektarda birkaç milyon böceğe rastlanabilir. Kuşlar ve öteki avcılar kısa sürede doyar, böylece böceklerin çoğu çiftleşmeye fırsat bulur. Bu stratejiye avcı doyumu denir. Erişkinler yalnızca birkaç hafta yaşar. 13 de 17 de asal sayıdır; bir görüşe göre bu yüzden döngüleri, daha kısa aralıklarla çoğalan avcılarla ya da komşu bölgelerdeki kuşaklarla nadiren çakışır.

Sources and further reading

Background reading: Periodical cicadas
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