Are there really more mosquitoes this year?

Mosquito / Culicidae
Credit: Insectarium de Montréal (René Limoges)
 Mosquito / Culicidae
Are there really more mosquitoes this year?

It’s hard to say whether there are more mosquitos from one year to the next or from one area to the other. Logically the population would have to be counted each season, in different areas, the data collected and then statistically compared. Without going to such lengths, certain factors, including the temperature and the amount of rain in spring and in summer, are nevertheless reliable indicators of the proliferation of mosquitoes in the course of a year.

A little reminder

The life cycle of mosquitos consists of several steps: the egg, the four larval stages, the pupa and the adult. The larvae develop in shallow stagnant water. Only females bite, and they do it to get the blood needed for the maturation of eggs, which in the vast majority of species survive the winter in icy waters.

Early or late spring?

In numerous species, eggs must necessarily undergo a number of weeks of great cold before hatching. Adults in those species are the first to emerge in the spring. If the season arrives late, cold and rainy, the females will stop annoying us at the beginning of July. On the other hand, an early, warm and dry spring will destroy part of the larvae, and our torment will be that much shorter. These species go through a single life cycle in the course of a year, so females eat only one blood meal, in the spring. Expect the next bites in the coming spring!

Rainy or dry summer?

Certain species have nonetheless developed the ability to produce more than one generation during a single summer. Thus, after the first cycle, eggs that are laid in the soil can dry out and then rehydrate depending on how much summertime rainfall there is. For these eggs to hatch, rain has to be abundant and stagnant pools have to form and endure.

What can I do?

It happens frequently that species lay eggs in the water of artificial containers such as neglected birdbaths or uncleaned eaves troughs – in a word, all those things we forget about and that hold rainwater for a number of weeks. Some species, like Culex pipiens, the principal West Nile virus vector, abound in these environments. So, to reduce mosquito populations around the house, we can simply avoid offering them environments that encourage their development – since we can’t control weather conditions!

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