Exact Answer: 4 To 6 Weeks
Cicadas are winged insects that produce the loud buzzing sound heard throughout the summer. They may be black, brown, or green coloured and spend most of their life underground.
There are two kinds of cicadas called annual and periodical cicadas. Annual cicadas are those that appear every year to mate and produce more eggs. On the other hand, periodical cicadas remain underground for 13 or 17 years before they emerge above ground to mate.
In 2021, periodical cicadas known as Brood X will surface after 17 years underground. They appear in different places like the region from Northern Georgia to New York. Cicada broods are also visible in the Midwest and to the west of the Mississippi River. Brood X is one of the 15 periodical cicada broods that surface in the US. Also knows as Brood 10 or the Great Eastern Brood, it contains three species – Magicicada cassinii, Magicicada septendecula and Magicicada septendecim, that appear in millions. These cicadas remain on the surface from late May to June 2021 for a span of four to six weeks.
How Long Will The Cicadas Be Here In 2021?
|Type Of Cicada Brood||Time It Lasts Above Ground|
|Brood X (comprising ofMagicicada septendecim, Magicicada cassinii and Magicicada septendecula)||Four to Six weeks|
Although cicadas have the lengthiest life cycle of any insect, they spend most of it underground in the nymph stage. Cicadas that emerge in 2021 have lived underground in their wingless nymph form since 2004. They survive by feeding on sap from tree roots.
In late May and early June, these nymphs emerge and live their remaining life cycle for two months. After courting and mating, adult cicadas lay their eggs which will hatch after four to six weeks. The adults then begin to die in late June and early July. Nymphs that hatch from the eggs will be buried 10 to 12 inches underground, feeding on the sap of trees by the end of 2021.
Why Do Cicadas Stay For So Long In 2021?
Cicadas emerge above ground for one reason only- the continuation of their species. Cicadas emerge when ground temperatures reach about 17-18 degrees Celcius in their nymph stage. However, they were growing and developing their adult body during the 17 years underground. So the cicadas will moult and shed their nymph skin. In the adult, winged form, male cicadas begin to court females of the species. To do so, males generate a loud noise, which is what we hear during summer nights. The cicadas then mate. This process lasts about a month, after which the cicadas die.
After mating, female cicadas lay their eggs in small twigs and branches, which hatch after about six weeks. Once they hatch, the nymphs fall to the ground and burrow their way into the ground. After becoming adults, these nymphs will surface above ground again in 17 years.
Hence, cicadas that emerge in late May will die at the beginning of July (in four to six weeks) after completing their life cycle.
Predators are the biggest threat to cicadas. Additionally, cicadas are clumsy bugs. Of the million cicadas that emerge, many die due to clumsiness and by getting eaten by predators. However, cicada broods can afford to lose a few thousand without harming the species’ chance of survival due to their sheer numbers.
Bood X set to surface soon is one containing millions of cicadas. They will be visible in 15 states in the United States including, New Jersey, Pennsylvania, Indiana, Delaware, Ohio, Georgia and New York. They emerge in late May and remain till early July. After living the rest of their life cycle, comprising four stages- moulting, courting, mating, and laying eggs, the cicadas begin to die.
The nymphs then hatch from the eggs and fall to the ground. They burrow into the soil, looking for tree sap. Hence, by the end of 2021, the nymphs would already be 10 or 12 inches under the surface. These cicadas will be visible again in 17 years, in the year 2038.