Reality bites: Facts about Flagstaff-area mosquitoes

Published on Aug 11, 2018 in the Arizona Daily Sun

Like all horror films, the scene starts tranquil – a streamside picnic or a softball game near a pond – until disturbed by an eerie sound. This year the buzz of mosquitoes has turned many outdoor Flagstaff events into fear fests, as the bloodsuckers come in for attack in broad daylight.

“Being frequently a target of a bloodsucking insect with no relief in sight is a downer,” said Dr. Gary Alpert, Director of the Center for Bio-Cultural Diversity at the Museum of Northern Arizona. Alpert studies insects and other arthropods of the Colorado Plateau, and is interested in starting a study of the floodwater mosquitoes that torment Flagstaff during the monsoon season each summer. The mosquitoes seem to be particularly bad in places where people want to recreate, such as Buffalo Park. Alpert notes that the Rio de Flag, which runs right through town, is ideal habitat because it is an intermittent stream that acts as a floodplain.

“I would not discount a whole town’s anecdotal chorus that it is worse. It means we should be trying to find out why.”

What makes the mosquito tormenting Flagstaff particularly terrifying is that, unlike vampires, they attack in bright sun and open areas. These mosquitoes are also particularly persistent and aggressive. And the resulting bite is more painful and irritating than other mosquito bites.

Alpert and Hugh Murray, an entomologist at the Coconino Public Health Department, identified this mosquito as Ochlerotatus trivattus, recognizable by a central dark stripe, with yellowish stripes on either side, and then dark outermost stripes. This species is common east of the Rocky Mountains, and deeply reviled in New Jersey, but not new to the Colorado Plateau. Ochlerotatus trivattus were spotted in Apache County as early as 1973, and Museum of Northern Arizona Curator of Ecology, Dr. Larry Stevens noted their presence in the Grand Canyon region in a 2007 paper.

The good news is that these mosquitoes do not transmit West Nile Virus. However, dog owners should be aware this mosquito can carry heartworm, so pets should be properly protected with heartworm medication.


You’ll rarely swat a male mosquito. The bloodsuckers are all females, who must drink blood to develop their eggs. The mosquito's taste receptors are on the bottom of her feet, so she first lands and probes for a tasty spot with her feet before starting to feed. Her mouth is composed of two separate tiny tubes bundled together, like an “out” straw and an “in” straw. Once she pierces the flesh, the mosquito pumps saliva down one of the “out” straw. The saliva has anticoagulants to thin your blood, so that she can easily suck it up the “in” straw. Your reaction to a mosquito bite is really a reaction to the injection of the saliva.

Once she’s sipped her fill, the mama mosquito finds a place to lay her eggs. Unlike stagnant water mosquitoes, the floodwater mosquitoes just need damp ground, which can come from heavy rains, or heavily watered gardens and yards. The eggs hatch within a day or two and the larva grow into biting adults within 5 days in ideal conditions, such as the warm days and nights Flagstaff has experienced recently.

According to Dr. Stevens, the floodwater mosquitoes have historically disappeared before the end of August.

“Now we have global warming, so they could be here longer,” warns Alpert. The eggs stay in the soil, waiting up to three years for the next warm rain.

No mo’ squitoes

Because mosquitoes taste with their feet, coating yourself in something they find distasteful keeps them from biting. There are plenty of home remedies, from consuming garlic or Vitamin B, to lathering on oils of tea tree, lavender, eucalyptus, lemon, peppermint, rose-geranium or lemongrass. However, Alpert cautions that none of the home-remedies have stood up to scientific study. The Center for Disease Control recommends repellents that contain DEET, Picaridin, IR3535, oil of lemon eucalyptus or 2-undecanone.

“Most entomologists prefer something with DEET,” said Alpert. “You’re out in the field collecting insects, you don’t want to be eaten alive.”