Ann Maree twitter
Swarmageddon has begun, with cicadas emerging from the ground (Ann Maree/Twitter)

Billions of cicadas are preparing to swarm the US east coast as the first of the insects begin to emerge from the ground.

Dubbed swarmageddon, the cicada invasion will last for around four weeks when the bugs rise from the ground to mate in trees - an event that takes place once every 17 years.

An area stretching from New York State through Pennsylvania and Virginia as far south as Tennessee will be affected by the invasion, with cicadas outnumbering humans by around 600 to one.

The insects have started to rise in Virginia, with locals posting photos of the red-eyed winged anthropods online. They have also been spotted in Maryland, to the north.

Hannah Cassidy Twitter
Cicadas will outnumber people by about 600 to one (Hannah Cassidy Twitter)

Cicadas emerge once every 17 years when the soil temperature around eight feet below ground level reaches a steady 17.5C.

While they pose no threat to wildlife or crops, the cicadas may cause some annoyance due to their noisy mating calls - their chorus reaches around 90 decibels, the same noise level as a subway train or a kitchen blender.

After emerging, the cicadas will find the nearest tree and start climbing, shedding their skin on the way. Once they have mated, they will disappear underground again until 2030.

Michael Raupp, an entomologist at the University of Maryland, told the Society for Science & the Public that swarmageddon is a not-to-be-missed event.

Cicadas climb trees to mate and emit a chorus equaling a subway train (Jared Hall/Twitter)

"Where the cicadas emerge, it will be spectacular. You see the insects in a mad, desperate dash for the trees so they can survive and mate," he said.

"Birds and squirrels will be eating them. It's life. It's death. It's romance. It's a massive display of Mother Nature's wonder - in my opinion, at its best."

John Coley, an entomologist from the University of Connecticut, also espoused the cicada invasion.

He told the Daily Telegraph: "The periodical cicadas are friendly insects and fun to watch. The people who say that it's gross are probably the same people who are quite happy to catch the subway in Manhattan in close proximity to a million-plus cockroaches. Give me cicadas any day."

Cicadas are light coloured when they come out of the ground and gradually get darker (Andrew Barrett/Twitter)
Cicadas are light coloured when they come out of the ground and gradually get darker (Andrew Barrett/Twitter)

While some Americans plan to enjoy the spectacle of swarmageddon, others are planning to take the opportunity to sample the insects, which some cultures consider a delicacy.

Jenna Jadin wrote the online cookbook Cicada-Licious while a entomology graduate student at the University of Maryland.

Her recipes include cicada dumplings, cicada pizza, banana cicada bread and cicada-rhubarb pie.

"Eating bugs sounds disgusting? If you have ever eaten a crawfish, lobster, crab, or shrimp then you have already eaten members of the class Arthropoda, of which insects are a part," she wrote. "So popping a big juicy beetle, cricket, or cicada into your mouth is only a step away.

Eating Cicada
Woman eats a deep-fried cicada (Erin Seagraves/Twitter)

"Many people all over the world eat insects and other arthropods both as a delicacy and staple. This is sensible because insects are nutritious. Insects provide as much protein pound per pound as lean beef."

Offering advice on catching cicadas, she said: "Newly hatched cicadas, called tenerals, are considered best for eating because their shells have not hardened.

"It is best to collect these in the very early hours of the morning, just after they have emerged, but before they have time to climb up out of reach. The best way to do this is to simply go outside with a brown paper bag and starting scooping them in."