Amateur Mosquito Investigation (or Getting the Biting Bastards Back)

• insects
• macro
• DIY

The situation is this. I live in the French alps at the moment, as I am working at the European Synchrotron Radiation Facility in the capacity of Junior Science Pimp (OK, assistant press officer). I am suffering from insect bites, delivered by species unknown, but the modus operandi fits mosquitos.

I did a quick search on the internet on the subject of insect bites and how to prevent them, and found a lot of old wives' tales, hearsay, and unsubstantiated anecdotes. The best site I have found on the subject (giving paper and experiment references) is here, but I will also be searching the scientific literature as soon as I have access to journal archives (it is a crying shame that access to these things is so expensive that only scientific institutions can afford licences to view them. We all deserve access to knowledge!), but in the meantime I am setting up a small experiment to see what, if anything, will repel the little individuals.

The set-up

This is not going to be rigourous by any stretch of the imagination. I'm making a lot of assumptions. Mainly I am assuming that the insects' behaviour is ergodic — basically, that running experiments one after the other will give the same result as having lots of experiments running at the same time. This is probably not reasonable since I'm dealing with icky imprecise biology and not nice, friendly quantum physics, but since I only have one test subject (moi) it's a necessary evil. I will try to note down any conditions that might make a difference (weather, how tasty I'm feeling, etc) but I may miss things and it's unlikely I can do a direct comparison. Rule of thumb/indication is what I'm aiming for here.

So, initially I will be testing three hypotheses, to be known as citron, Marmite, and chemical warfare. My control period will be last week, which royally sucked in terms of mosquito attack.

Control

Last week (3-9th May, 2009) I was the lucky recipient of 5 bites on my forearms, 2 on my torso, and 3 on my legs. The weather was warm, averaging around 22 degrees, with occasional showers. I was sleeping with the window open.

Citron

Hypothesis: "Try putting a white saucer or plate out w/a mixture of lemon dishwashing liquid and water where you are staying. The mosquitos are attracted to the lemon scent, land in the bowl and drown."

Well, I don't have lemon dishwashing liquid but I do have lemon syrup and dishwashing liquid so I have put out a saucer with those. We shall see. This test will be conducted over the course of the next week or so, with the time I spend in a different city next weekend deducted and made up after.

Marmite

Hypothesis: "Vitamin B1 (thiamin) is claimed to provide protection. Excess amounts of the vitamin are excreted by the body through sweat and urine and, in theory, mosquitoes are repelled by its smell (a scent undetectable to humans)."

After that, I will be going back to England for a few days. A perfect opportunity to stock up on Marmite and test the effect of extra Vitamin B1. A 4g serving gives 0.23 mg of B1. I can't find any data on how much B1 you're supposed to need to get an effect — in fact I seem to find a lot of data suggesting that it doesn't have an effect, but this is about first-hand testing, so I will persevere. The internet says I should take 100mg, which is quite a lot of Marmite — 16 grams. I'm not sure what the density of Marmite is (the internet is strangely silent on this point) but I think that's at least four slices of toast. I may take supplements as well if I can't manage that level of consumption.

Chemical warfare

No test would be complete without the high-tech, destruction-of-all-life-forms solution. The recommended agent is DEET — N,N-Diethyl-meta-toluamide to its friends — and I'll be trying to get some at 30-50% concentration. Worryingly though, 33% concentration (as used by the USA army) only protects you for 3-6 hours, leaving me unprotected for a good portion of my sleep time. Also, DEET should not be used on damaged skin, so presumably once you've been bitten it's too late to start using it?

Future methods I may give a go

Lasers, catnip, lemongrass, eucalyptus, imitating female mosquitos, rotting plants and swamp water diluted a billion times...

Results to follow.