Imagine witnessing millions of blood-sucking insects swarming before your eyes. Early this August, a horrifying, huge, vertical swarm of mosquitoes was filmed in Russia. A tornado itself is already terrifying, but a tornado of mosquitoes is far more bone-chilling.

Mosquitoes

There are over 3,000 species of mosquitoes around the world. Most mosquitoes stay within several hundred feet, especially when they are in their hatching period. The top speed for a mosquito is about 1.5 miles per hour.

American Mosquito Control Association says they are capable of transmitting diseases such as malaria, yellow fever, dengue, filariasis and encephalitis. They can cause weight loss and decreased milk production in animals.

Swarming Insects

Insects swarm for different reasons. Mosquitoes' seasonal swarm strength, as mentioned by an article published in Huffington Post, is dictated by the weather.

Warm weather means swarm season. Across Alaska, it is in the spring and summer when the mosquitoes form in groups. Meanwhile, rain and flooding events like hurricanes can also cause huge mosquito hatch-offs.

Live Science explains, on the other hand, that crickets have a different swarming season as they tend to stay in groups to avoid or intimidate their predator. The survival rate of a cricket is higher when it stays in a group.

In a study published in the Feb. 17 issue of the journal Nature, researchers explained how crickets fared with and without their band.

"In repeated experiments, we found that within two days, 50 percent to 60 percent of the insects transplanted out of the band were dead because something ate them," said Patrick Lorch of the University of North Carolina in a press release published by Eurekalert. "On the other hand, we found no deaths during the same period among the crickets we monitored that stayed with the band."

Other Case of Mosquito Tornado

Mosquito tornado is a phenomenon that is very rare. The last one spotted was in Portugal. A photo of it was accidentally captured by photographer Ana Scarpa, who was then visiting Leziria Grande at Vila Franca de Xira.

IFL Science notes that the swarm extended around 300 meters (1,000 foot) into the air. Witness a swarm of mosquitoes by checking out the video below.