Scotland’s Giant Mozzies

We’ve had several reports recently from people who have been attacked by ‘giant mosquitos’, asking whether this is ‘normal’ in Scotland. The short answer is yes, it is normal, there are several native species of mosquito in Scotland. Some species don’t bite at all and of those that do, it’s only the females that will bite you...

Culex pipiens, (C)Pieter van Breugel

Of the world’s 3,000 species of mosquito just one percent are found in the UK, 10 of which are known to occur in Scotland. Fortunately none of these are disease-carriers or pose a threat to human life.

European distribution maps of two mosquito species found in Scotland.

Mozzies like to breed in moist, humid places, so they can really be found anywhere, in towns and the countryside, as long as there is undisturbed water to be found, such as pools, ditches, water butts, even bird baths.

It’s been a pretty good summer overall in Scotland, although quite humid in many areas. With Covid-19, perhaps people are getting out and about more than usual in their local patch, exploring new bits and so encountering mosquitos when they wouldn’t normally.

Also, there may be areas around towns and villages which have benefitted from being managed less, so pools of water and damp areas remain where they might not otherwise be allowed to and that’s perhaps helped mosquitoes to expand their breeding area.

Mosquito larva. Photo Sven Petersen

Mosquitos begin life as filter feeding larvae consuming the remnants of other insects, leaves and algae. As adults, the males feed only on nectar, so they have no need to bite you. Females however, need to supplement their diet with protein so their eggs can develop, and this is what they’re looking to find in blood. Depending on the species this blood meal can be obtained from birds, reptiles or mammals, including you and me.

Anophoeles plumbeus females are persistent biters. Photo via ECDE

You have probably noticed however, that while all humans are born free and equal, from the female mozzie’s point of view, some are indeed more equal, than others. At times you will have noticed that you seem to be be getting ravaged by the blighters while others you are with seem blissfully bite free, or perhaps the other way around. This is largely to do with genetics and around 20% of us tend to get more than our fair share of mozzie bites.

A pair of Culex pipiens – can you identify the biter? Credit Free Nature Images

There are some popular myths around why this is the case, such as wearing perfume or eating salty and potassium-rich foods increasing your appeal to female mosquitoes, or nicotine making smokers’ blood less attractive. While science doesn’t support these theories, there are several reasons why researchers do believe some of us get bitten more or less than others. A few of which we can mitigate, but the rest are inequalities we were born with and which we just need to take on the chin (…. or ankle, back of the knee, elbow or wherever it may be).

There has been a lot of research into the reasons why you might be more susceptible to mozzie bites. According to the Smithsonian, latest studies into this suggest that reasons why you might be more or less appealing to mosquitoes include:

  • Blood type – mosquitoes seem to be particularly attracted to those with an O blood type. It’s thought that they are able to detect this preferred blood because about 85 percent of people secrete a chemical signal through their skin that indicates which blood type they have.
  • CO2 – mozzies are attracted to CO2 and can detect carbon dioxide from as far as 164 feet away. So if you are producing more of it, you’re more of a target. This can be due to being overweight, drinking alcohol or exercising.
  • Bacteria – some studies have suggested that particular types and amounts of bacteria that live naturally on our skin make us more appealing, so if you were unable to take a shower for some reason, you could increase your attractiveness ( to mosquitoes at least!).
  • Clothing – at least one study has suggested that dark colours are more visible to mosquitoes.
  • Natural chemicals – some of us naturally produce more lactic and uric acid, ammonia and other substances than others, which mozzies like very much and detect through their antennae. Exercise also increases the build up of these substances in our bodies. Some people also seem to produce more chemicals that repel mosquitoes.
  • Pregnant – studies have shown that pregnant women attract twice as many bites as others, likely due to the fact that they produce more carbon dioxide and are little bit warmer.

While the above could make you more susceptible to mozzie bites, if you are with someone who ticks those boxes, you may become less of a target. So perhaps the best advice for those of us who are hoping to fly below the mozzie radar is simply to choose our friends very carefully!

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