In the states north-east of here they have emerged, listen closely we could probably almost hear them. Not really, but it is probably pretty loud indeed!
Here in Indiana we call them locusts but that is a misnomer for locusts belong to the taxonomic order Orthoptera (like crickets and grasshoppers). Cicadas belong to the order Homoptera (like aphids and leafhoppers).
That is all very scientific but the 17-year cicada is every scientist’s, mathematician’s, naturalist’s, and entomologist’s darling subject and to which this blog is dedicated.
Magicicada is the genus of the 17-year cicadas (as well as the 13-year cicadas which emerge in the southeastern states and sometimes overlap).
There is mathematical certainty to their emergence. It happens in only one place on the Earth and only every 17 years.
Rather like an eclipse, the cicada emergence is a rare phenomenon. When the spring temperatures begin to reach above 63 degrees F as many as 1.5 million cicada individuals an acre will take over the deciduous forests of northeastern United States. The nymphs have been underground for the last 17 years feeding on the root fluid (xylem) of the forest trees.
So why life cycles in large prime numbers? Some say to withstand or eliminate predators from receiving periodic population boosts and coupled with the sheer numbers (called predator saturation) they survive.
However, the most widely accepted hypothesis is to prevent hybridization between broods with different underground cycles during a period of heavy selection pressure brought on by isolated and lowered populations.
Ready for the quiz? It is all in the genes or in the case of the periodical cicadas; just one single gene controls their life span. They emerge as adults, white, but darken within an hour.
The males sing for their mates, often in choruses, receptive females respond with wing-flicks. Mating occurs in “chorus” trees while both male and females have the ability to mate multiple times, although most females only mate once.
They then cut v-shaped slits in the bark of young branches and lay 20 eggs each to a total of over 600 eggs per female. In 8-10 weeks these hatch, drop to the ground and burrow to feed again for 17 more years.
They do relatively little damage to mature vegetation and cicadas do not bite or sting. Their proboscis can pierce skin when handled and this can be painful but they do not carry diseases or pose serious health problems.
Sometimes the trees show some wear the year before an emergence (that may have been exasperated because of last year’s draught) because of the nymphs feeding on the tree roots.
Moles do well a year before their emergence as they eat the underground nymphs and wild turkeys do well the year after as they gorge on the adults.
Native Americans were known to have eaten cicadas, they would string them over the fire and eat the meat from their shells, and why not? The periodical cicadas have been feeding on some of the most wholesome material on the planet and digesting it for over 17 years.
Would you be willing to eat a roasted 17-year cicada? Indeed, the wild turkeys are sounding yummy this year and if you know any Northeasterners, ask if you can make it for Thanksgiving and you’ll tell them all you now know(if they haven’t gone deaf) about 17-year cicadas of the insect genus Magicicada.
The Bug Files