Has the heatwave got the better of the mosquitoes in recent days? On social networks, many Internet users are wondering. No more bites, spots, no more nuisances at night…. One of the (rare) advantages of the heat wave which has gripped France. But then, will we live a summer without mosquitoes? Don’t throw away your lemongrass right away. Because nothing is less certain.
The mosquitoes have not disappeared, they are hiding
If you have the impression that you have encountered fewer mosquitoes for several days, it is not an illusion. But that doesn’t mean they’re gone.
“No, they are probably not absent: they are often just less visible during heat peaks”explains Dr Gérald Kierzek, medical director of True Medical.
In question, their physiology. Unlike mammals, mosquitoes do not regulate their body temperature. When it’s very hot, they’re just trying to survive.
“Heat can accelerate their life cycle, but beyond a certain threshold, it bothers them and they become less active in broad daylight. They take refuge in the shade, in cooler areas, or survive better in small water points that remain damp,” specifies the doctor.
Same observation for Mathieu de Flores, entomologist at the Office for Insects and their Environment (OPIE), who recalls that mosquitoes become much less active during episodes of extreme heat and favor cool, vegetated places.
In addition, our habits of quickly closing windows during periods of high heat may have slowed the entry of resistant pests into bedrooms. Giving us a little respite.
Heat can temporarily slow down their reproduction
The heatwave also affects their reproductive cycle.
“Mosquitoes do not like extreme heat; above a certain temperature, their activity drops and their survival becomes more difficult. If it is very dry, many small breeding places can dry out, which temporarily limits the laying and development of larvae,” explains Dr. Gérald Kierzek.
The high temperatures actually lead to the evaporation of many small pools, ditches or puddles in which certain species deposit their eggs. As for the tiger mosquito, which generally lays eggs near very small water reserves, it can also see some of its breeding sites disappear when everything dries up.
The tiger mosquito is probably… near you
Be careful not to declare victory, however.
“The tiger mosquito moves little and breeds near homes, in very small containers of stagnant water: saucers, gutters, buckets, tarpaulins, water collectors… In other words, they do not really disappear: they take advantage of the slightest residual water, sometimes in your home or in the neighbors’ homes”recalls Dr. Gérald Kierzek.
A few milliliters of water are enough to ensure their reproduction.
“Water points can evaporate during high heat, which reduces larval breeding sites. But as soon as there is water left in a container, a poorly drained gutter or a damp corner, this can be enough to restart egg-laying” reminds the experts.
In other words, the respite currently observed could only be temporary. Specialists also expect a rapid resumption of their activity as soon as slightly more moderate temperatures return or the first rains.
Dr. Gérald Kierzek’s 5 tips to keep mosquitoes away this summer
Even if mosquitoes seem to be fewer in number during hot weather, they are still present. To limit bites, Dr Gérald Kierzek recommends a few simple actions.
1. Stop them from entering the house
“We avoid leaving the doors open, especially in the evening, with a flow of light inside which attracts mosquitoes. We also install mosquito nets on windows to provide ventilation without inviting insects, as well as on doors. Finally, a mosquito net above the bed allows you to spend a night without bites.”
2. Remove all standing water
The tiger mosquito lays eggs in sometimes tiny volumes of water. Remember to regularly empty saucers under flower pots, buckets, toys left outside, tarpaulins or even clean the gutters.
3. Run a fan
Little known, this reflex is nevertheless effective. By stirring the air, the fan disrupts the flight of mosquitoes, which have a much more difficult time landing on the skin. As a bonus, it brings a little freshness during summer nights.
4. Use repellent wisely
“Using a repellent can help keep mosquitoes away. Those with essential oils are generally effective, but we are still careful with their use. Some are not very suitable for children, others are photosensitizing and gadgets like bracelets do not work.”
When possible, the doctor recommends favoring physical protection, such as mosquito nets.
5. Wear long, light-colored clothes
In the evening, it is better to opt for loose, light and light-colored clothes. They limit mosquito access to the skin and more effectively protect the most exposed areas, particularly among children.
In summary, although mosquitoes seem to have deserted our evenings for a few days, they have not disappeared. They are simply waiting for more favorable conditions to resume their activity… and their bites.