This Week’s Creature Feature: Late Summer’s Orchestra
Cicadas are a group of insects that spend most of their life underground but emerge in the summer to sing and breed. They have been present since the Upper Permian Period, about 250 million years ago, with some giant specimens found with conifer fossils. Now they are present all around the world with more than 3,000 species.
In Maryland, 16 species can be divided into three basic types: the annual, the 13-year and the 17-year cicadas. The yearly variety lives from three to nine years underground feeding on the juices in tree roots. Because of overlapping lifespans, some annual cicada nymphs crawl out of the ground each year. They are distinguished by dark eyes and dark-brown or -green bodies.
The 13-year cicadas have two species and, because of brood overlap, are present most years. They have red eyes and reddish wing edges.
There are also two species of 17-year cicadas. Brood X is the 17 group that emerges en mass and has not been seen since 2004. They are due back in 2021. They also have red eyes and reddish wing edges.
All cicadas feed on the sap of trees, through the roots as nymphs and through green branches as adults. After the nymphs emerge, they change into winged and noisy adults.
Their flying is not delicate, and they are a feared event-crasher; outdoor weddings were canceled or moved indoors in 2004 by parties fearful of being struck by the hard-hitting bugs.
The two-inch insects have a diaphragm-like membrane, the timbal, that they make buckle and vibrate, creating a distinctive loud noise. In 2004, when there were hundreds if not thousands of singing adults in each tree, in some places the noise was measured well over 100 dB. That’s nearly as loud as a power lawn mower.
Adult cicadas spend two to three weeks singing, mating and laying eggs before dying. They lay eggs into the branches of deciduous trees. The branches where the eggs were laid will die as the eggs hatch and the young nymphs start to feed. The nymphs will then drop out of the trees and burrow underground to begin years of subterranean living.
When Brood X emerges, the sheer numbers overwhelm predators and allow for successful reproduction. In one more year, there will be whole new batches of cicada recipes and tales of people being hit by living missiles, fat predators and piles of dead bugs.