As the Sierra melts out this trail season, you can look forward to many things: brimming alpine lakes, fields of wildflowers, rushing brooks, lush green meadows, snow-capped peaks, and everyone’s perennial favorite, mosquitoes. Though they only weigh 2.5 milligrams each, what they lack in size they make up for in numbers. There are over 3,000 species of mosquitoes, 200 of which can be found in the United States. Upward of a dozen varieties are commonly found in the Lake Tahoe region.
Broadly, there are two types of mosquitoes: Univoltine species which have one brood (hatch) in a year, and multivoltine varieties which have two or more broods in a year. In the spring and summer, Tahoe is home to the Aedes species, a day-biting, univoltine mosquito that thrives in high alpine environments. These mosquitoes lay their eggs on grass and dirt in flood zones during the summer. Then these eggs hunker down all winter until the snow melts in the spring. Four to six weeks after the last of the snow succumbs to warming temperatures, it’s hatching time for these flying bloodsuckers. Aedes make up 90% of Tahoe’s mosquitoes. Fortunately, they are not vectors for disease and are considered a nuisance at worst. After July, we say bye to our Aedes frenemies.
Once summer is well underway, Tahoe’s multivoltine varieties take flight. These dawn and dusk biters lay their eggs in standing water providing a food source for many aquatic species (they do have some redeeming qualities). While Aedes mosquitoes provide us with red, itchy welts, some of Tahoe’s multivoltine species can be a real cause for concern. Although small in number, the Culex tarsalis mosquito is the primary vector for the West Nile virus, a disease that can be transmitted from birds to mosquitoes and on to humans.
Like us, mosquitoes enjoy living in Tahoe and don’t anticipate leaving. For outdoor recreationists or backyard BBQ aficionados, here are my tips and tricks to finding harmony among the buzz.
Mosquito Precautions
Pictured left: Culiseta incidens mosquito- life cycle (eggs, larvae, pupae, flying adult).
*Use insect repellent. Safe and effective options include DEET, picaridin, and oil of lemon eucalyptus (OLE)
*Treat your outdoor clothing and gear with a permethrin insect repellent spray before heading out. You can also buy pre-treated clothing.
*Wear light-colored, loose-fitting, long-sleeved shirts and pants, and other skin-protective clothing. This makes it more difficult for mosquitoes to reach your skin and the heat and CO2 they are attracted to.
*Keep your skin (and especially your feet) clean and free of fragrant lotions, perfumes, colognes, or soaps as mosquitoes are attracted to these odors.
*Dogs can be affected by mosquitoes just the same as humans. Stick to repellents specifically made for dogs and consult your veterinarian for recommendations.
Pro-Tips
Pictured right: Dave Granlund Cartoon Big Mosquito Problem
If mosquitoes are testing your patience, put on an extra layer of sun protection and step into the light. Mosquitoes prefer shady, humid areas.
Speaking of humidity, don’t camp in shady, wooded areas with high moisture. Avoid lakes, creeks, and meadows. Sound familiar? It should! Leave No Trace principles suggest choosing a campsite at least 200 feet away from water.
If your biome, like mine, is especially attractive to mosquitoes you may want to plan your trips on the trail for later in the summer or the fall when the day-biting mosquito population has dropped.
Consider enjoying dawn and dusk, peak mosquito-feasting hours, in the comfort of your tent.
Never apply potent bug repellents like DEET to waterproof gear or plastics. The chemicals can damage the material.
Mosquitoes are attracted to some humans over others but it has nothing to do with diet or hair/eye color. A recent study suggests mosquitoes are attracted to certain microbes that live on your skin. Your unique microbial makeup may or may not attract mosquitoes.
Interesting Facts
Pictured left: Culex tarsalis mosquito larvae – Photo Credit Toogee Sielsch
Only female mosquitos bite (such actually) but blood is not their primary food source. Mosquitoes feed on nectar but need the protein found in blood to grow their eggs.
After the big 2016/17 winter, Tahoe experienced a higher than average population of Aedes mosquitoes following a buildup of unhatched eggs resulting from previous low snow years.
Our Other Flying Friends(?)!
When you see a high population of dragonflies, be grateful. Dragonflies are mosquito-eaters!
Yellow Jackets, a.k.a. meat bees mostly nest in the ground. If you create a vibration on the ground, yellow jackets may feel threatened and can attack. Otherwise, they mostly just want your sugar and protein.
The Yellow Jacket population can be devastated by hard freezes, a period of a least 4 consecutive hours of air temperatures below 28 ⁰ F, in April and May. The mix of warmer days causes the bees to come out of hibernation and get caught in the hard freeze overnight.
Many thanks to El Dorado County Vector Control’s Toogee Sielsch, Vector Tech II, whose insights on the ins and outs of Lake Tahoe’s mosquito population inspired this article. If you have more questions about the fascinating, albeit slightly annoying lives of mosquitos, you can contact El Dorado Vector Control at 530-573-3197.
