We're about a month into the emergence of Brood X or Great Eastern Brood cicadas, which means the nuisance is nearing an end. "From past cycles, broods last about 4-6 weeks from their first emergence," University of Maryland entomology professor Daniel Gruner tells the Washington Post, which reports dead cicadas are already piling up. That presents another annoyance: the odor of billions of rotting cicadas. "Cicadas are no different than other animals," explains Paula Shrewsbury, a colleague of Gruner. "As part of the decay process there are a number of interactions between enzymes and microbes that result in the 'smell of death.'" While spreading out the bugs will help, the smell is expected to linger until the cicadas are fully decomposed, "returning nutrients back in the soil under trees that will support their young for the next 17 years," Shrewsbury says.
Male cicadas die off after mating. Female cicadas do the same once they've laid their eggs—usually 20 to 30—in slits made in tree branches, per WLWT. Around late July and early August, those eggs will hatch nymphs, which will journey underground to feed from tree roots, next emerging in 2038. They'll benefit from the nutrients of their brethren in the meantime, as will the trees, which tend to bloom more in the year following a cicada emergence, per WLWT. "Every one of those cicada bodies is essentially like a pellet of fertilizer," Wright State University biological sciences professor Don Cipollini, who plans to compare the effects of nitrogen-rich cicadas on lawn grass with those of synthetic fertilizers, tells WDTN. "So, you could literally sweep them off of your sidewalks or off of your driveways and scatter them in your yard." Be sure to check your gutters, too. (Read more cicadas stories.)