Nature as a nuisance, meaning mosquitoes and midges

Nature bites back

Why we are on the mosquito’s diet is a question to which the answer is clear: the females use our blood as a source of protein for their eggs. How to withstand nature’s nuisance is rather more of a challenge, certainly less simple and unambiguous as well, because a Scandinavian summer is the obvious equivalent of a Nordic banqueting hall.

The beautiful, almost endless days, the bright sunlight and the rainy in between hours accompany the mosquitoes that are present almost always. July is the worst month. Mosquitoes and other insects are to be found everywhere and a natural plague in places with water, marshland and thriving bushes. They sting and they bite while some species like the little black midges even gnaw at your skin.

Some years ago while staying at the Glenelg Inn (Scottish Highlands, near the ferry to the Isle of Skye) I could not believe my eyes after someone exclaimed “Midges are coming!” All jumped to their feet, leaving drinks and cocktails behind and started running away from the terrace to a safe indoor shelter. Adult people fleeing in panic from an invisible threat, locking doors and windows firmly behind them? It caused great merriment, so, I went outside to see for myself. And I can still recall the grinning face of Christopher Main, owner at the time. He did warn me indeed…  

A place without mosquitoes, what a wonderful world it would be! Fuelled by an all too obvious frustration, more than once this thought crosses the mind. We lack compassion and search for a zero-tolerance approach. The arrival of those tiny creatures signals our poetic skills to a temporary leave of absence.

Elegant dance in the air, the color of wings blending in with the sunlight gaze of dawn. Theirs is the mastered art of a silent approach – their presence unexpected. No softer touch the delicate legs can perform, leaving the butterfly astounded.

 

Why are there so many mosquitoes?

 

Mosquito presence peaked in July 2015 – a Swedish local newspaper even  proclaimed this year’s summer to be the most unpleasant ever. Fishermen were instructed to wear a mosquito coil on their hat, an advise that immediately prompted more radical solutions: a ghilly suit would be convenient under the circumstances! Notwithstanding the fact that this type of camouflage clothing really would be very effective – some might have praised heaven for this moment to arrive – yet, others do not greet this alternative with open arms.

 

Weather conditions and warming of the earth

July 2015 was also the warmest month ever recorded for the globe. The National Oceanic and Atmospheric Administration (NOAA) reported that with an average of 16,6 Celsius this July’s temperature has been the highest monthly temperature in the 1880-2015 period. Statistics show that the increasing temperatures are to be found everywhere: land surface, sea surface and ocean surface come up with the same pattern. It stands to reason that higher temperatures are favourable weather conditions to many insects, implying the possibility of a shift in their natural environment.

In Sweden there are some 50 different species of mosquitoes, differing in habitat and habit. Some are just lazy vampires, waiting for their bait to appear while others are extremely active and aggressive, chasing after their meal. This, for an example, is the case with the 2015 aggressor that hatches from the flooded riverbanks. Because this year spring was late to arrive and in addition there has been a lot of rainfall, riverbanks and their surroundings stayed an area of swamp for a longer period than usual. It caused an invasion of big black mosquitoes that apparently opted for the detect-lock-attack approach. Flying at high speed in a straight line like jet fighters, these mosquitoes simply hit you in the face by surprise.

In families it can be a running gag each year: who will have to endure the most mosquito bites? It is known that mosquitoes bite and sting in order to harvest the proteins from our blood but why are some of us more prone to bites? How delicious we are is influenced by different factors that could play a role. This said, too much hope is not to be put into the thought that now you will learn exactly the trick to outsmart the mosquitoes once and for all. For better or for worse, it is almost all about genes.

 

How to influence our attractiveness

Genetic factors account for some 85 percent of the variation between people. Nevertheless there are other factors that play a role as well. Mosquitoes use carbon dioxide, moisture and heat, scent and vision to locate their hosts. But alas and alack, influencing our attractiveness will affect only 15 percent of the total.

Attractive blood. Only to remind you of a fact. People with blood type O are bitten almost twice as often as those with blood type A. Blood type B is in the middle.

What is that smell? A mosquito will speed up to reach target under quite a few circumstances. These insects smell the carbon dioxide which is exhaled by us and other mammals. The insects can locate us at far distance, meaning about 50 meters (164 feet). Noteworthy fact is that the more carbon dioxide is emitted, the more attractive one will be. It explains why small persons generally will be bitten less and why pregnancy is coming with a good chance of being victimized twice as much because pregnant women exhale some 20 percent more carbon dioxide.

Bacteria are delicious. Even though we are not constantly aware of all the skin bacteria we carry along – fortunately enough one might add –  these colonies are still a mosquito’s best friend. A piece of information to read and subsequently to brush aside is the dazzling number of chemicals when it comes to hand odors: a 2000 study counted 346, of which 277 were potentially attractive to mosquitoes. Not washing your hands, or feet for that matter, for a day or two results in multiplied bacteria and a changed pH: now less acidity and more alkalinity, meaning more ammonia. And that is exactly what a mosquito calls a delightful smell. Seemingly, they even will bite in a pair of smelly socks.

Exercise means higher body temperature and producing sweat. Mosquitoes smell the lactic and uric acids, ammonia and octenol (also known as mushroom alcohol) among other attractive substances and will gladly join you.

I see you! Along with scent, mosquitoes use vision, so it seems. Wearing outstanding colors might help the traceability of a meal.

The lower, the tastier. Mosquitoes do have a habit of biting our feet and ankles and for a reason. These areas have more robust bacteria colonies which -so to speak- stand out from the crowd.

 

How to impede the real outdoor nuisance – beat the mosquito!

Always look at the bright side of life, so, is there anything at all what we can do? Yes, although it will not guarantee a mosquito-free summer. Light a campfire, welcome a breeze. Mosquitoes like neither smoke nor wind. And wearing loose fitting clothes will hinder the mosquito and other insects as well. Nevertheless it is a fact that midges prefer to sneak in through the legs of your trousers, therefore a cord or something with a similar use could be handy. Garments that have been treated with an insect repellant could help too. Textiles that are really difficult for mosquitoes to get trough do exist, look for densely woven materials like G-1000.

Last but not least: an insect repellant. Several studies found that there are alternatives for the toxic DEET repellant. Plants like lemon eucalyptus are effective to a certain degree, but really interesting are the results of two 2013 studies (more in the article by Richardson). The three best plants being repellant, irritating and toxic for the mosquitoes were citronella, cinnamon and thyme. Other studies added cumin, coleus and lemongrass to the list, as well as hairy basil. We could go on for a while here. But essential oils evaporate quickly, therefore some vanillin was added and yes, this can extend the efficacy of the substances.

That’s a welcome bonus and intriguing enough to include in an amateur experimental method next summer. Also then we will try the ‘glue-them-roast-them’ method, invented by the Swedish Anna Rosenberg. A friend told us it worked really fine with midges. What you will need is a not too expensive barbecue with a lid, briquettes and some vegetable oil. Place the briquettes in such a way that they form a ring to create a domino-effect. Light the first briquette and close or cover the grill. Now put some vegetable oil on the whole surface of the lid.

Sit and wait, they will come and find their grave.

 

 

References and more reading

 

• Joseph Stromberg – Why do mosquitoes bite some people more than others? – published in the online Smithsonian Magazine, July 12, 2013.
• Jill Richardson – Why mosquitoes bite some people and not others – and the surprising non-toxic way to avoid bites – published on the website www.rawstory.com, June 24, 2015.
• Laurie L. Dove – What if mosquitoes went extinct? – published in the science section of Howstuffworks, 01 June 2015.
• Ramya, K. & Maheshwari V. – Development of eco friendly mosquito repellent fabric finished with Andrographis paniculata plant extracts – International Journal of Pharmacy and Pharmaceutical Sciences, Vol. 6, Issue 5, 2014 (link to article)
• NOAA, Global Analysis – July 2015 (link to Maps and Time series, article and overview)
• For a picture of the ultimate midge & mosquito trap, the deadly BBQ, click here!

 

 

Images (fly fishing and fire): courtesy of J. van Marsdijk.