June 1, 2013 at 11:17 AM ET
The march of the cicadas is hitting prime time on the East Coast, and that means researchers are getting their best opportunities to study how the burrowing insects have weathered the past 17 years. They're finding some amazing comebacks, and some puzzling absences as well.
Over the past few weeks, billions of cicadas have been rising out of the ground, over a swath of territory ranging from Georgia to Connecticut. These bugs are part of a group known as Brood II, which emerges every 17 years to crawl and fly, mate and die over the course of just a few weeks. Between one emergence and the next, the immature bugs are dug into the soil, living off the watery fluid in plant roots.
The pace of the emergence is dictated by soil temperature: This year's cicada outbreak has been a bit slower than expected, due to a cooler-than-usual spring. But University of Maryland entomologist Michael Raupp says the conditions now appear to be right for cicadas to make their appearance across most of Brood II's traditional territory. Magicicada.org's map of cicada sightings points to hot spots in Virginia, Maryland, New York, New Jersey, Pennsylvania, Connecticut and Rhode Island. For residents in those states, this may be as good as it gets.
"If they don't have 'em now, they're going to be in for a very bad case of cicada envy," Raupp joked.
Loud life, quick death
The emergence of the nymphs is just the first step in the insects' 17-year ritual: After they come out, the cicadas shed their hard shells, unfurl their wings, crawl up trees or buildings, and seek out their mates. Raupp and other cicada fans have been reveling to the insects' mass choruses, which can get as loud as 90 decibels. (One aficionado has compared the cacophony to the sound of "Star Trek" phasers set on stun.)
And then there's the denouement. "We're starting to see the first dropouts," Raupp said. "They've completed the biological imperative in the tree canopy, and we're starting to see mortality."
If you're expecting to see cicadas all over the place, you'll be disappointed. "These things are very, very patchily distributed," Raupp said. "You can go a distance as little as a quarter-mile or a half-mile, and one location will have thousands or tens of thousands of cicadas in the treetops, and the other location will have nothing."
If you come across a bug infestation, be not afraid. Cicadas are not harmful to humans. Some folks may find them disgusting, but others find them delicious.
The signs of emergence have been seen in some surprising locations. "Cicada cells are very airtight, as they survived Hurricane Sandy in Staten Island," Elias Bonaros reported on the Entomology-Cicadidae discussion forum. "I found loads of exit holes right where the sea met the shore and were supposedly submerged under many feet of water!"
That resilience is in line with reports going back almost two centuries. In his classic work, "The Periodical Cicada," entomologist C.L. Marlatt mentions a case where a "gentleman in Louisiana" dammed up some property in 1818, covering the soil with 6 feet (2 meters) of water. When the water was drained away more than a year later, cicadas were found "in a fine, healthy state, ready to make their appearance above ground, that being the year of their regular appearance."
Other changes wrought by humans can be more injurious to the cicadas. "The most damaging of all perturbations would be the creation of hardscape," Raupp said. "When that happens, it's devastating to the cicada population. For example, what was a cornfield 17 years ago, that has now been regraded to be a condominium or townhouse complex. Any disturbance of 60 centimeters [2 feet in depth] is going to extirpate any cicadas in that area."
Some bug-watchers are already coming across problem areas. John Cooley, a cicada expert from the University of Connecticut, said there are some "surprisingly silent" patches of land in Virginia where Brood II was expected to emerge. "We're not sure what explains these absences — the woods look perfectly fine for periodical cicadas," he wrote on the Entomology-Cicadidae forum.
Have you experienced the emergence? Or have you missed the bug-out? Either way, feel free to weigh in with your comments below.
Video tributes to the cicada:
Previous chapters in the cicada saga:
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the NBC News Science Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with NBCNews.com's stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.