The beast arrives unannounced, landing on a welcome strip of flesh that offers a delicious buffet. It pierces the victim’s skin simultaneously injecting a special fluid to make its task simpler and faster. Then it draws the blood it so desperately needs for its young. Witness, the female mosquito at work. The mosquito is an insidious beast with the power to keep an adult wide awake with its steady, high-pitched wingbeats. Where is it? Will you find it before you feel that inevitable attack on your skin?
Mosquitoes have relatively short lifespans with males living 10 days or less. Females can live up to two months and some can hibernate up to six months. During their brief lifetime, females can lay eggs every three days, up to 300 at a time. All mosquitoes require standing water for their eggs to develop through larva, pupa and adult. (Yes, that is a clue for later.)
The ‘bite’ of the female is actually a piercing via serrated proboscis. For what it’s worth, males don’t care about you — they feed on nectar, but females need a blood meal to nourish their developing eggs. Some mosquito species prefer humans, others birds, cattle or other animals. Feeding time varies with some species preferring evening or nighttime hours, others daytime.
But how does she find you? Is it just good luck? Mosquitoes are attracted to the carbon dioxide we exhale along with certain chemicals we exude from our skin and perspiration. A mosquito can detect C02 from as far as 25 metres away. She will fly back and forth through the C02 plume until she locates her victim… and there you are!
For most of us, the main irritation of a mosquito bite is the itching and red welt it produces. This is caused by our own allergic reaction to the insect’s saliva used as an anticoagulant. Our immune reaction releases histamine, there’s itchiness, the bump and redness… you know this story.
Though worries over mosquitoes is minor, we know they spread disease. We have watched for West Nile virus in recent years, and now the Zika virus raises concern. Both are serious, but the ‘big hitters’ of mosquito-borne disease remain malaria, yellow fever, dengue fever, chikungunya, and others. Here, the focus should be on getting the right protective vaccinations/medications prior to any travel abroad.
The best protection against mosquitoes is prevention. Start by making their reproduction more difficult: get rid of any stagnant water around your property, however small: old tires, pet dishes, bird baths, empty flower pots, pool covers, etc.
Chemical protection is a sound second option. Insect repellant containing DEET in concentrations of 30 to 50 per cent is very effective. Also effective is oil of eucalyptus, but only the synthetic version (p-methanediol). You can ignore the ‘natural’ repellents such as geranium oil, citronella or peppermint as they are of limited effectiveness, as are bug zappers which mostly kill flies and moths.
What about bats and birds? Don’t they help? Not really. Neither consumes many mosquitoes. The two main mosquito predators are fish and dragonflies. Fish will feed on mosquitoes before they fully mature. Dragonfly larvae eat mosquito larvae, and adult dragonflies prey on adult mosquitoes. Go dragonflies!
Mosquitoes can turn a backyard barbeque or quiet time on the patio into an unpleasant experience, and don’t get us started on trying to sleep with that one rebellious bug in your bedroom. Get rid of standing water and stock up on the DEET; you’ll be just fine.
Written by Dr. Paul Martiquet, Medical Health Officer for the Sunshine Coast and Powell River.