Sunday, April 11, 2021

Cicadas are Emerging- Help Map Them

Brood X area

Many people know periodical cicadas by the name "17-year locusts," but they are not the locusts of the bible. Those were a type of migrating grasshopper. However, if you live in the area of this year’s emergence, when Brood X of the 17-year cicadas arrive in mid-May, it may indeed feel like a plague for a few weeks. When they emerge in mass, you can report periodical cicadas using the Cicada Safari App, available on the Google Play Store or the Apple Store.  This will help scientists map the full extent of Brood X. If it does not feel like you are being inundated and you only see a few cicadas, they are probably stragglers from other broods and should not be reported.

The Washington Metropolitan Area will be at the epicenter of the Brood X emergence which will cover parts of 14 states. In Virginia there are eleven primary broods of the 17-year cicada and two primary broods of the 13-year cicada. Every year they emerge somewhere within the Commonwealth, but Brood X due any week now is one of the largest and impacts our area in Northern Virginia including Prince William, Loudoun, Fairfax, and Fauquier counties and into the

Cicadas, probably both Magicicada septendecim and Magicicada cassinii will emerge from the soil and climb onto nearby vegetation and other vertical surfaces. They then molt to the winged adult stage. The emergence is tightly synchronized, with most adults appearing within a few nights. Adult cicadas live for only two to four weeks. When the 17-year periodical cicadas emerge the density can be shocking and noisy. It is common to have tens to hundreds of thousands of periodical cicadas per acre, but there are records of up to a million and a half periodical cicadas in an acre. This is far beyond the density of most other cicada species and half of the cicadas are “singing.” Male cicadas sing quite loudly by vibrating membranes on the sides of their abdominal segment. Male songs and choruses are a courtship ritual to attract females for mating. If you hear the cicadas chorus in the spring take a picture and report thefinding to the University of Connecticut that is running the mapping projectusing their phone apps.  

The males’ choruses have been known to drive people to distraction-stay inside with the windows closed if needed. However, for most people, the droning song of the cicada is nothing more than a slight annoyance. To me the “song” sounds like wind on a cell phone connection, but you can listen to the actual chorus on the u-Tube video. Most people are more familiar with the dogday cicada that is prevalent annually in mid-summer. Their song is later in the summer and not as persistent.

The 17 year or 13-year periodical cicada is black, with red eyes and orange legs. “Adults have clear wings with distinctive orange veins. When viewed from the front the wings form an inverted "V" and meet at the top like a roof.” After mating, females lay their eggs in narrow young twigs slicing into the wood and depositing up to 400 eggs in total for each female in 40 to 50 locations each. It is the egg laying that does most of the damage associated with periodical cicadas. Cicada eggs remain in the twigs for six to ten weeks before hatching. The nymphs do not feed on the twigs and all but the youngest trees will recover.

1 comment:

  1. I’m in Austin Texas and right now there are cicadas everywhere in my neighborhood. June 24,2023. One flew right into my front door and tried to claw its way inside.