While I wait for another chance to get out, between work and wildfires, I thought I'd post a few things...
Mosquitoes! The bane of every outdoor (and even indoor) summer activity, and an unavoidable nuisance for every backpacker, how do you deal with them? Well, it may help to know a little about them.
There are over 3,000 species of mosquitoes and they kill about one million people every year. Here in California, we have about 50 species (most in the Aedes, Anopheles, Culiseta, and Culex genre with most California mosquitoes in the Aedes genre), in addition to other invasive species like Aedes albopictus (2011, known to carry yellow fever, dengue fever, Chikungunya fever, Usutu virus and maybe Zika virus) and Aedes aegypti (2013, known to carry dengue fever, chikungunya, Zika, Mayaro and yellow fever viruses, among other diseases).
Mosquitoes "bite" with their 'mouth parts' or "proboscis", which is a group of six different parts: The labella are at the tip of the proboscis, they are two sensory probes, which help the mosquito look for a good place to bite. The labium, the visible sheath you can see, folds back like an accordion, as the mosquito's maxillae saw through the skin while the mandibles hold the skin apart. Then the labrum go to work, probing around under the skin trying to find a good target. Meanwhile, the hypopharynx pumps in saliva to stave off our immune response, lubricate the proboscis, keep blood from coagulating and dilate our blood vessels. Once a blood vessel is found, the hypopharynx lays on the labrum creating a tube which pulls in blood, but the mosquito filters out the water in the blood so it can get about five to ten times more nutrients than if the blood was unfiltered. But the mosquitoe's saliva not only contains an anesthetic to dull the sensation of all the damage and an anticoagulant to keep the blood from clotting, it ALSO stops our immune response, which is how it spreads diseases. Since its saliva thins the blood, it makes it easier for a virion (a complete viral particle) in the saliva to hop into our blood stream and infect our body.
OKAY, SO HOW DO MOSQUITOES FIND US?
Glad you asked. If you're a fan of certain survival "reality" TV shows, you've probably seen people smear mud all over themselves. Suffice to say, while this may feel good at first (and make for great television), mosquitoes are smarter than they are! Mosquitoes can find us in several ways; movement, body heat, but they have a very keen sense of smell. In fact, it’s the primary reason they are attracted to us and other animals.
Carbon dioxide, and many of the fragrances we emit are irresistible to them. Mosquitoes likewise find a variety of scents unappealing (more on this later). Also, different species of mosquitoes prefer bacteria and sweat. Others are attracted to carbon dioxide and certain hand odors. Genetics effect your mosquito appeal, but so does what you consume. Just like wearing a sweet-smelling perfume in the forest attracts insects, consuming certain food and beverages also has an effect (more on this later).
ON THE TRAIL
Every backpacker knows, mosquitoes are just a part of the summer outdoor experience. At times however, the bugs can go from a nuisance to real pain in the neck (pun intended!). But there are a few things that you can do to keep the little pests from ruining a trip. The following is a list of tips I’ve found helpful.
1. REPELLENTS – If the natural options don’t work for you (more on this later), there’s always DEET! It’s the active ingredient in many outdoor mosquito products. Apply it to your exposed skin. DEET is known to be very effective when applied properly, but it does have one major drawback: it is a SOLVENT and will damage synthetic fabrics (nylon, polyester, rayon, etc.) and certain GEAR! If you need something to apply to synthetic clothing, use a permethrin based insect repellent. Permethrin is a powerful chemical that kills insects on contact, but may cost more. Also consider Picaradin as a topical repellent, and while far safer than DEET, use as if it were DEET. Meaning, use only on exposed skin (ALWAYS read the labels, and do your research!)
2. CLOTHING/COVER - Mosquitoes are more attracted to dark colored clothing, so cover-up with light colored clothes. Most likely this has to do with their ability to sense the heat which dark clothing tends to retain better than light clothing. It makes sense to cover the exposed parts of your body to prevent the bugs from getting close to your skin. Unfortunately, mosquitoes can bite through cotton of t-shirts and jeans. Having multiple layers and/or tightly woven fabrics helps. Some recommendations are clothing like GoLite trekking pants and ExOfficio long-sleeve shirts (which has their InsectShield treatment). Gaiters may protect your ankles and create a good seal for your lower legs (I typically insert a drawstring on my pant leg hems).
3. MOSQUITO NETTING - A mosquito head net that covers your head and neck will prevent bug bites when the bugs are fierce, but make sure it's “NO-SEE-UM” netting (for head nets, I prefer black because you can see through it easier especially when the sun hits it). It may look unusual, but it will prevent bug bites. Besides, it won’t be so funny-looking to others when the bugs start flying!! Use a hat underneath the netting to keep the net away from your face and neck. Some swear by the Backpacking Light mosquito headnet to a no-see-um headnet; The only skin left then are your hands, I sometimes have a pair of leather climbing gloves, but you can just apply a mosquito repellent.
4. AVOID THEM - The time of day when mosquitoes are most active tends to vary depending on the species and the weather. Mosquitoes are most common in marshy, boggy areas where there is plenty of stagnant water for them to reproduce, green leaves, and blood-filled animals. They also like to hang out in wet meadows, stands of trees, and thickets where they rest on a blade of grass or flit about in the shade of a tree waiting for you to walk by. So it helps to know where they likely to hang out so you can get your bug repellent ready and your clothing adjusted. I always have my repellent and headnet in a pouch on my belt.
5. TIMING - They don’t fare well in the wind or in cold temperatures, so if you are planning a trip, consider avoiding the peak mosquito hatch that happens just after “green up;” bugs are usually at a minimum by the fall, especially after the first frosts. If you are out in bug season, then plan a route that stays away from marshy lowlands; stick to the ridges and wide rivers where there is usually a breeze. Mosquitoes tend to be most active in the morning and evening, so especially avoid bug-prone areas then.
6. DON’T BE LAST - When hiking as a group on a trail, it helps NOT to be the last in line. It takes time for mosquitoes near the trail to home-in on the CO2 emitted by your group as you pass by. The first few in line will be gone by the time they are aroused by your scent.
7. KEEP CLEAN – As I’ve mentioned before, mosquitoes can find their victims by their scent. That scent is emitted through your breath, but also through your skin. Specifically, your SWEAT! Sweat is odorless at first, but the bacteria on your skin "ripens" the ammonia, lactic acid, etc. and breaks it down making you stink. So, as your clothes (and sleeping bag) begin to stink, you start to ring the dinner bell. Mosquitoes are even known to flock to hanging sweat socks! Yeah, aside from most people thinking they were going to get AWAY from doing laundry in the wilderness (to say nothing of being exiled from camp), it’s a little more work getting enough water to do your laundry in addition to drinking and cooking, but if you’re sweaty and/or the mosquitoes are out, this may save you. To do laundry, just get a 2-gallon plastic bag (or a waterproof dry-bag), squirt in some soap (I only bring a liquid shampoo-body wash, seems to be fine for laundry), then shake-rattle-n-roll! You can also buy citronella soap to bathe, but it's a little more expensive and the effect only lasts about a half hour (depending).
8. CAMPING. When you first pull into camp, you’ll probably get swarmed. Try to find open, wind-prone areas that are away from water sources. I’ve found the swarm calms down once they figure out you’re a tough bite. And they really disperse once I start a smoky fire (depending on wind direction), by using damp/rotted wood or not giving the fire enough air. Tarps can be sufficient during bug season, but you may consider an inner net or bivy sack, or just a headnet. If you’re in a tent, and you have room for a candle, consider packing a citronella candle or two (just be careful). Some use a Mountain Laurel Designs SoloMid with its Innernet. In the past I’ve used A-frame tarps in conjunction with bivy sacks.
9. STATE OF MIND – If all else fails, this is your last resort! This is perhaps my best defense against vicious swarms of mosquitoes. It’s just a reality of the wilderness in some parts, and it’s not really something you can fight or stop. It’s just something you deal with. Even horrible bugs are surprisingly tolerable if you take the measures described. I find comfort in knowing that bad bugs are just a temporary feature.