Cicada barbara lusitanica
Life and Mathematics. Cicadas only emerge after a prime number of years cycle. African cicada Magicicada septendecim has a 17 years cycle. A close relative has a 13-years cycle. Others a 7-years cycle. C. barbara, shown here, has a 5-years cycle. Why do they do it?. To avoid to coincide with predators life cycles peaks. In Stephen Gould’s example, a cicada that emerges every seventeen years and has a predator with a five-year life cycle will only face a peak predator population once every eighty-five (5 x 17) years, giving it an enormous advantage over less well-adapted cicadas. C. barbara is a big cicada, up to 2.5 cm long with a wingspan of 7 cm. It can be distinguished from its closest relative Cicada Orni by the continuous singing of the first from very similar C. orni by the song, a continuous singing in the first against discontinuous chirps in the second. The decoration of the wings with black points is typical of C. barbara. C. barbara is considered a plague for olive trees since they suck the olive sap. When nymphs they go underground where they live for 5 years from which emerge to become adults after the last molt.
Spotted at a pine tree and evergreen oak forest. Dehesa de Valdelatas
Camera Model: NIKON D500. Exposure Time: 1/160 sec.; f/22; ISO Speed Rating: 2200. Focal Length: 90.0 mm. No flash fired. DSC_2993, 2977, 2969, 2967
Lat: 40.53, Long: -3.68
Spotted on Jul 6, 2018
Submitted on Nov 6, 2018
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