By Laurie Sullivan
Mosquito magnets: There’s one at every barbeque. But, why’s it have to be me?
While other guests seem oblivious to marauding mozzies, I’m the one doing a slightly demented version of the German slap dance.
So, why me and not you?
It seems that after countless hours of research and oceans of insect spray and repellents, scientists still don’t know.
Insect expert, Dr Cameron Webb, an entomologist based at Sydney University, filled me in what we know (and don’t know) about mozzies.
FACT 1 – There are hundreds of mosquito species. They all have slightly different preferences when it comes to the blood they prefer.
FACT 2 – Only females bite. Blood is the nutritional hit they need to develop eggs.
FACT 3 – Initially our carbon dioxide and body heat attract her, until she reaches the point when she can actually home in on the particular aroma of her victim’s skin. Then, it’s dinner time.
FACT 4 – There are roughly 400 chemical compounds on human skin. It’s likely some, perhaps all, play a role in attracting (or repelling) mosquitoes. This heady concoction is produced by bacteria mixed with sweat, but individual genetics, diet, or physiology probably all play a part. Dr Webb believes it’s these differences from one person to another that probably explains why some of us are mozzie magnets while others aren’t.
FACT 5 – Blood type (particularly type O), being pregnant or drinking beer (he could be on to something there) could make us more attractive to mosquitoes. However, this research is based on only one mosquito species: other species may produce different results.
FACT 6 – Research shows the distinctively striped Aedes aegypti – the tropical species that transmits yellow fever, dengue fever, and Chikungunya fever – is especially attracted to the lactic acid in sweat. They’re often found in cool, shady places in urban areas and - unlike most mosquitoes that bite mainly at at dawn and dusk - they also feed throughout the day. So, a sweat-removing dip in the pool or a shower, followed by a thorough application of insect repellent before stepping outdoors at sunset is definitely worthwhile.
FACT 7 – A study of the malaria-spreading Anopheles gambiae mosquitoes found that they are attracted to Limburger cheese, of all things. The bacteria that give this cheese its particularly pungent aroma are closely related to germs that live between our toes, which explains why these mosquitoes are attracted to smelly feet. (Interestingly, Aedes aegyptidon’t have a foot fetish – just another reason why studying the biting behaviours of different species is so frustratingly complex!)
FACT 8 – Nothing you can eat or drink will stop you being bitten by mosquitoes. (Including garlic or vitamin Bsupplements – just a couple of the mythical repellents people have pinned their hopes on.)
One final fact – Everyone gets bitten
I admit to taking perverse comfort in learning that just because some people don’t react to mosquito bites, it does not mean they aren’t being bitten. Sure, some of us get bitten more than others, but it’s highly likely that everyone gets bitten to some extent.
Mosquito saliva isn’t just saliva. Along with any virus or malaria parasite the mozzie might be infected with, it contains a coagulant or blood thinning agent that keeps the blood flowing. When bitten, we all react differently to the saliva – just as we do to the many environmental, chemical, or food allergens we encounter in our daily lives.
“People who don’t react to mosquito bites may think they haven’t been bitten,” Dr Webb said.
“Actually, they’ve probably been bitten as much as their itchy friends.”
(If you are adamant that you don’t get bitten, you are indeed rare. Dr Webb will want to hear from you!)
The danger of complacency
Dr Webb warned that people who don’t react to mosquito bites may become complacent and could be at higher risk of getting one of the many mosquito-borne diseases found in tropical regions overseas, or in Australia.
Researchers around the world are trying to unscramble the irresistibly smelly cocktails on the skins of us mozzie magnets. Until they do, there’s good news and bad.
“The bad news is that there isn’t much you can do about it other than to apply an effective insect repellent to your skin,” he said.
“The good news is that the mozzie magnets may one day help scientists isolate a substance, or a mixture of substances, that will create the perfect lure to use in mosquito traps. Then all of us might be able to say goodbye to insect repellents.”
Dr Webb’s advice to us mozzie magnets is simple:
Don’t worry about why you are a favourite feast on the mozzie menu. Instead, simply accept the fact, and focus on choosing the right repellent and use it correctly.
Travelling soon? Read more on protecting yourself from biting insects or call Travelvax Australia on 1300 360 164.