every 102 years
To think of cicadas as "deciding" something is anthropomorphizing; that is, using words that describe human attributions with things that don't really think as humans do. What probably happened is that those cicadas which happened to have a prime number cycle tended to avoid having predators match their periodic appearances and so increased relative to those that didn't, and as a consequence, got eaten. This is Natural Selection. Incidently, only Periodic cicadas have prime number cycles (17 or 13 years); there are also Annual cicadas which as their name implies, appear every year.
The periodic cicadas spend most of their lives as underground nymphs, only emerging after 13 or 17 years, most likely to reduce losses by satiating their predators.The evolutionary strategy used by cicadas of the genus Magicicada make use of prime numbers. These insects spend most of their lives as grubs underground. They only pupate and then emerge from their burrows after 7, 13 or 17 years, at which point they fly about, breed, and then die after a few weeks at most. The logic for this is believed to be that the prime number intervals between emergences make it very difficult for predators to evolve that could specialize as predators on Magicicadas. If Magicicadas appeared at a non-prime number intervals, say every 12 years, then predators appearing every 2, 3, 4, 6, or 12 years would be sure to meet them. Over a 200-year period, average predator populations during hypothetical outbreaks of 14- and 15-year cicadas would be up to 2% higher than during outbreaks of 13- and 17-year cicadas. Though small, this advantage appears to have been enough to drive natural selection in favor of a prime-numbered life-cycle for these insects.
Cicadas likely evolved to have prime-numbered life cycles as a strategy to avoid synchronization with other insect species or predators. By having longer life cycles that are not easily divisible by other common periods, cicadas can reduce competition and increase their chances of survival and reproduction. This unique adaptation may have provided an evolutionary advantage, leading to the prevalence of prime-numbered life cycles among cicadas.
I dont now i need some one to tell me :(
The commonwealth games happen every four years.
Suppose the cicadas come out every C years and a predator comes out every P years. Then the life cycles of the predator and the cicadas will coincide every LCM(C, P) years. The predator will want it to happen as often as possible while the cicadas want that to happen as seldom as possible. If C is co-prime with P then the cycles coincide after CP years - which is best for the cicada.Suppose the cicadas come out every C years and a predator comes out every P years. Then the life cycles of the predator and the cicadas will coincide every LCM(C, P) years. The predator will want it to happen as often as possible while the cicadas want that to happen as seldom as possible. If C is co-prime with P then the cycles coincide after CP years - which is best for the cicada.Suppose the cicadas come out every C years and a predator comes out every P years. Then the life cycles of the predator and the cicadas will coincide every LCM(C, P) years. The predator will want it to happen as often as possible while the cicadas want that to happen as seldom as possible. If C is co-prime with P then the cycles coincide after CP years - which is best for the cicada.Suppose the cicadas come out every C years and a predator comes out every P years. Then the life cycles of the predator and the cicadas will coincide every LCM(C, P) years. The predator will want it to happen as often as possible while the cicadas want that to happen as seldom as possible. If C is co-prime with P then the cycles coincide after CP years - which is best for the cicada.
Cicadas
You probably mean cicadas that remain underground for 17 years, emerge, lay eggs and die
Cicadas spend most of their lives sleeping. They wake up for a few weeks, mate and then die. They only show up every 13 or 17 years.
They are called cicadas
17 years
ANSWER:They appear about 7-9 years. Some larvae stay underground for 13 years and others for 17 years.
Cicadas have a 17-year or 13-year life-cycle, depending on the variety.
Every twelve years they will coincide.
No
the census is every 10 years, the presidential election is every 4....that means they coincide every 20 years. (2020, 2040, 2060, 2080, 2100......)
They are called cicadas (seh-cay-da) and they lay eggs in the ground and the larvae come out every 7 years.