Here cicadas, there cicadas, everywhere……
Nature glories in being mysterious, but recently she has been downright confusing. Why cicadas now? These clumsy, noisy creatures are bumbling through the air looking for a mate but not having much success. Turns out that the raucous critters are four years too early.
Back in 2004, millions of periodic cicadas in Fairfax County created a din rivaling that of a lawn mower. These cicadas were to spend their 17 formative years underground as a larva quietly sipping sap from tree roots. Then, in a mysterious synchrony, they would emerge to shed their exoskeleton above ground. They would then leave a crispy, tan exuvae behind as they fly off in their adult form.
So why, suddenly, a 13-year cycle instead of 17? First, a little about these insects.
Weird looking, but not harmful
Cicadas cannot bite or chew, nor can they sting, so they pose no risk to curious kids. They can use their beak-like proboscis to pierce twigs to consume tree fluids. They are a scrumptious treat for most wildlife from birds to mammals to fish to fungus, and with only a short life as an adult, under two weeks, the periodic cicadas typically survive by overwhelming their predators with sheer numbers. As large and noisy as these insects are, they are easily found and munched. Those who do not get eaten get to mate.
As adults, that’s the main goal for cicadas — find a mate. Females quietly cruise while the males beat a come-hither call with their bodies. As a result, a lot of noise.
The lucky surviving females lay their eggs in thin twigs on trees and then die. The twigs eventually snap, resulting in dead leaves called flagging that hangs off tree tops. The tiny larvae sup on the fluids in the twig, grow, and soon fall to the ground. There they burrow underground to start their count to 17 (or 13 if that is their cycle). This elegant dance takes but a few weeks, and then the tree tops are quiet again.
Periodic cicadas baffle humans, even when they are expected. How can they count to 17? How do they all emerge at the same time? Why are they flying into my face? Why are they all over the road? Cicadas were pre-Ice Age residents, and our dominance of the landscape is a relatively recent phenomenon. As the ground cicadas dig into is paved over, the patient larvae emerge only to bump their heads and lose the chance to mate or be a meal to a grateful predator.
Do cicadas count?
The early emergence of the periodic cicadas is not a new phenomenon. Chris Simon, a professor of ecology and evolutionary biology at the University of Connecticut, surmised that the cicadas have four-year development cycles, which could explain why “stragglers,” cicadas that are four years too early or too late to the party, regularly occur. Others proffer that global warming could speed up the larvae development. Scientists estimate that this spring’s emerging population represented ten or less percent of the total population. If that’s accurate, just wait ’til 2021!
Cicadas may creep out humans with their size, noise and numbers, but they shout the primacy of nature. For a few short weeks, nature cannot and will not be ignored. That alone makes the mystery of the cicada inspiring. Perhaps that is why genus name is Magicicada.
For now, Fairfax County residents can marvel at the noisy, bumbling mystery. We may never know all the answers but can take joy in the wonder.
Author Suzanne Holland is the Assistant Manager at Hidden Oaks Nature Center in Annandale, Va. Photos provided by Park Authority staff and photographer Tuan Pham.