to eric, about cicadas

Hi, Eric: Here is an interesting article concerning cicadas’ lifecycles. It is true that not all of them, but some species of cicadas go through a 13- or 17 lifecycles as what we had talked about this morning, you might be interested to read it. Dad


[edit] Lifecycle
After mating, the female cuts slits into the bark of a twig and deposits her eggs there. She may do so repeatedly, until she has laid several hundred eggs. When the eggs hatch, the newborn nymphs drop to the ground, where they burrow and start another cycle. 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 13- or even 17-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.


Cicada shell left behind in the south of France
The insects spend most of the time that they are underground as nymphs at depths ranging from about 30 cm (1 ft) up to 2.5 m (about 8½ ft). The nymphs feed on root juice and have strong front legs for digging.
In the final nymphal instar, they construct an exit tunnel to the surface and emerge. They then moult on a nearby plant for the last time and emerge as an adult. They shed their skins when they moult, and their abandoned skins are often found still clinging to the bark of trees.