Nfld. & Labrador

'Love is, literally, in the air': Funnel clouds of flies in Gander explained

Preston Freake captured video of a mating phenomenon while out for a walk on a popular walking trail in Gander last week.

Turns out mysterious swarms of swirling insects at Cobb's Pond were just getting it on

A column of mayflies in a still from a video of a mating flight over Cobb's Pond in Gander. (Submitted by Preston Freake)

Preston Freake and his girlfriend Stephanie Hill were out for a walk around Cobb's Pond in Gander when they came upon a scene straight out of a horror movie.

Swarms of flies rising in columns above the trees around the popular walking trail in central Newfoundland stopped them in their tracks.

"It was absolutely amazing to watch it, they would keep moving up and down and changing positions, some of the funnels were 40 or 50 feet high," said Freake, who captured the phenomenon in a 50-second video.

"We tried to get through the flies as best we could without getting swarmed by them, you just couldn't do it, there were too many of them ... so we swerved around," he told CBC Radio's Central Morning Show.

Preston Freake and Stephanie Hill had never seen anything like the swarm of insects they captured on video on a walk around Cobb's Pond. (Submitted by Preston Freake)

"By the time we got through you had it in your hair, and your nose, and your mouth, it was everywhere."

It turns out what was happening last Thursday was a bit of insect romance.

The adult stage is just for sex.- Tom Chapman, biologist

"They're mayflies," said Tom Chapman, a biologist and professor at Memorial University in St. John's. 

"For these animals —  love is, literally, in the air. These are mating flights." 

Chapman has never personally witnessed a scene like that, but he has seen other videos of mayflies looking for a mate en masse.

Funnel clouds of flies were captured on video at Cobb's Pond in Gander 0:50

"Those columns were thousands of males ... for whatever reason they choose that place to gather and as a group, they're attracting females to them and they'll mate in the air."

The males have four legs that go forward to grasp the female in flight. They'll mate, decouple, and she'll lay anywhere from 100 to 300 eggs in the water.

Short lifespan

There are about 100 known mayfly species in Newfoundland and Labrador, and for most, the adults will only live for a few days.

"There's one species, not in the province, where the adult lives for five minutes, so it's all about mating," said Chapman.

Amateur photographer Mardon Erbland captured this image of a Spiny Crawler Mayfly last year while it was on a concrete retaining wall near Outer Cove Brook in Outer Cove. (Submitted by Mardon Erbland)

Despite the name, not all species choose to emerge in May from the creeks and ponds where they can spend the first couple of years as immature nymphs.

That can happen any time during the summer, depending on the species.

Not harmful to humans 

Finding yourself in a swarm of mayflies is no picnic, but at least they don't bite. 

That's because the adult mayfly has one goal, and one goal only.

"The adult stage is just for sex ... they don't feed at all, their guts are completely filled with air," said Chapman.

"They don't do any eating, so they have no mouth parts to bite, they have no stingers or venom with which to cause pain, they're as harmless an insect as you can imagine."

This Pronggilled Mayfly nymph was found in a pool of clear, vegetation-filled water, in a small marshy area at Torbay beach. (Submitted by Mardon Erbland)

Freake posted the video of the swarm on his Facebook page, and some speculated on whether poor water quality due to an old dump site in the area was the cause.

But Chapman said witnessing a mating flight is actually a good thing when it comes to the environment.

"Some species are fairly robust to pollution, but many aren't, so if there's runoff into the water — agricultural, urban development, factory pollution — they're the first to disappear," said Chapman.
 
"So these large mating flights in the Cobb's Pond area would suggest that the quality of the watershed in the area has been improving. If this is something they haven't seen in years past, but are now seeing in large numbers, it's a good sign."

   

With files from Central Morning

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