Last week we broke some news that here in the DMV some will see Brood XIV cicadas this year (Virginia), others will not (DC), and some might (Maryland). If you are fortunate enough to live in one of the twelve states where Brood XIV are known to occur, how will you know if cicadas are about to grace your yard? As many of you know, periodical cicadas are quite patchy in their distribution. In my neighborhood in Columbia, Maryland, folks along my street had tons of Brood X cicadas back in 2021, but just a few streets away, nary a cicada was to be seen. Several factors feature into local distributions of periodical cicadas. Changes in land use are primary factors. Periodical cicadas depend on woody plants as key places to conduct their boisterous choruses, mating rituals and locations to deposit eggs that usher in the next generation. Although soil-dwelling nymphs can feed on roots of herbaceous plants, xylem fluids from tree roots support fantastic densities of cicada nymphs as they grow underground for seventeen years. If you live in a neighborhood where development has denuded trees and removed soil in the last seventeen years, your chances of Brood XIV emerging in your yard are slim. Likewise, if your house sprouted up in what formerly was a field of hay or corn, your chances of welcoming periodical cicadas are, well, not so hot. Habitat fragmentation and urbanization with attendant impervious surfaces and soil compaction are two factors thought to disfavor populations of periodical cicadas. In several locations in the eastern United States, populations have dwindled or been extirpated over the last two centuries.
Beneath this stately old tree, a raccoon ravaged this lawn in early March. Were periodical cicadas the object of its gastronomic desire? Image credit: L. Kenigsberg
As periodical cicadas complete their juvenile development, here are some clues to help you know if you will see cicadas this spring or not. First, if your landscape supported cicadas back in 2008, odds are excellent that you will see them again this year. If you have moved into a home sometime after 2008 and you live in one of the states where Brood XIV historically appears, simply ask one of your long-standing neighbors if they saw cicadas seventeen years ago. If you live in Georgia, Indiana, Kentucky, Massachusetts, North Carolina, New Jersey, New York, Ohio, Pennsylvania, Tennessee, Virginia, or West Virginia, you can see which counties in your state reported Brood XIV back in 2008 by visiting the Cicada Mania website. There are also several clues you can see in the landscape around your home over the next month or so that signal the presence of cicadas. First, let’s talk about a glorious feast that is underway for small wild and domestic mammals as periodical cicadas prepare an exit strategy from their subterranean crypts. Four years ago, as a presage to the massive emergence of Brood X, a curious homeowner sent fascinating images of impressive excavations of turf beneath a fine old tree. The perpetrator of this crime was a pesky raccoon intent on digging for its dinner. The lawn was, well, just collateral damage on the way to a fine meal. While the identity of the subterranean morsel was never confirmed, this type of behavior is characteristic of many small mammals that will find cicada nymphs and adults irresistible this spring and go to great lengths to find them.
After feasting on periodical nymphs beneath my holly tree, this handsome fox headed for the hills and almost escaped my camera.
Also, during the early days of spring in 2021, the year of Brood X, while emptying some coffee grinds in the compost at 6:30 AM, I surprised a very handsome red fox in the process of excavating a thirty-foot-long patch of earth beneath my stately Burford holly. A couple quick turns of the shovel revealed several Magicicada nymphs about six inches below the surface of the earth. Casual site visits to my neighbors’ gardens and further inspection of my landscape revealed several locations where fox and friends had been busy in Columbia, Maryland enjoying cicada snacks. Both foxes and raccoons have excellent night vision, a must for their nocturnal forays, and an extremely keen sense of smell that allows them to detect prey beneath layers of fallen leaves and soil. These wild small mammals are not the only ones whose special creature powers include super olfaction. A dog’s sense of smell is estimated to be more than 10,000 times more acute than a human’s. And yes, if it hasn’t started already, soon inquiries will arrive posing the question: “Why is the dog digging up my yard?” Chances are good that Fido knows a good snack when he smells one. Please, just don’t let him eat too many.
How might you know if cicadas will emerge in your yard? Here are some clues. Small mammals like squirrels, foxes, racoons and skunks are on the hunt for cicadas, turning over the soil in lawns and beneath trees. In moist soils cicada nymphs sometimes build mud turrets over their exit holes and in other places vast numbers of round dime-sized holes will appear. Under stepping stones and flagstone walkways, numerous cicadas may be found in their galleries. Amazing expanded forelegs shaped by millions of years of evolution enable cicadas to move earth and shape their escape tunnels.
In moist soils like this, cicadas build mud turrets over their emergence holes.
Soon it will be time for a suburban safari to your backyard to spot additional signs of the arrival of periodical cicadas. Look for holes in the soil about the size of a dime within the dripline beneath trees that have been in the ground for seventeen years or more. Historically, oaks, maples, crabapples, and hollies seem to be the big winners in my landscape. In addition to holes, periodical cicadas often build domed caps or tubular extensions known as turrets over their escape tunnels. This may be more common in wetter soils. If your landscape includes stepping stones or flagstone pathways over soil, lift a few and you may discover lateral tunnels as cicadas encounter the impenetrable barrier and attempt to make their way to the edge of the barricade to reach the world above ground.
Lifting a stepping stone may reveal cicada nymphs peering out of their escape tunnels. Image credit: Kristin Jayd
No holes under trees? Don’t panic, new holes may show up over the next several weeks. During past emergences of periodical cicadas, a common question has been, “how do cicadas moved about underground and how did they construct their exit galleries? The answer lies in the clever adaptations of their forelegs. Their forelegs bear greatly expanded femurs and tibias which act like the blade of a shovel to move soil. Millions of years of evolution for a life in two worlds, one underground and one above the earth, have perfected the tools necessary for cicadas to succeed in both. In upcoming episodes, we will learn more about these remarkable insects.
Acknowledgements
Bug of the Week thanks L. Kenigsberg for providing the nice image of lawn pillaged by a raccoon that served as the inspiration for this episode. Kristin Jayd and Paula Shrewsbury also provided images and assisted with videography.