Why Some Summers Are So Appealing for Mosquitoes

2018/6/30 17:55:15

Since mosquito larvae are entirely aquatic, they need a source of standing water (like your flower pot) that will remain until they are ready to emerge as adults. You can go a long way toward avoiding being bitten by assuring that there are no convenient sources of standing water near you to promote larvae growth.




By Heath MacMillan, The Conversation, SMITHSONIAN.COM, June 22, 2018:


As you pack your bags for the cottage or campground this weekend, don’t forget to bring light clothes with long sleeves — and a truckload or two of insect repellent. Spring has come and gone, so welcome to mosquito season.

How much we enjoy summer depends a lot on how many mosquitoes there are waiting for us outside. Their bites are itchy and their drone annoying, but there’s also concern that mosquitoes carrying dangerous diseases are knocking on our door.

So what makes some years worse than others?

You don’t have to be an entomologist to notice that the mosquito population size can vary from year to year and place to place. Last June, I couldn’t set foot outside my Ottawa home without being bitten. Meanwhile, Winnipeg was experiencing its lowest mosquito count in four decades.

This year is far from mosquito-free, but I can at least enjoy peace for about 10 minutes before they find me.

What causes mosquito populations to balloon and shrink? In short, it’s a combination of weather and climate — mosquitoes are very sensitive to their environment.

Temperature and rainfall are two major predictors of mosquito abundance, and this is for a good reason: These two factors have a massive effect on their survival and ability to reproduce.

How much it rains at one time, when it rains, how long a cold or warm spell lasted and when it happened all matter when it comes to predicting what kind of mosquito season lies ahead.

Mosquitoes, like most insects, are cold-blooded, or ectothermic. Unlike us, their body temperature closely matches the temperature of the environment (air or water) around them. If it is cold outside, they are cold. If it is warm outside, they are warm. Any time spent outside of their comfort zone can slow or stop their development or even cause them to be injured and die.

In order for most mosquito larvae to grow, temperatures need to be above a threshold, which varies, depending on the species, but is typically around seven to 16 degrees Celsius.

Since the larvae are entirely aquatic, they also need a source of standing water (like your flower pot) that will remain until they are ready to emerge as adults.

This means cold or dry conditions that hit at the right time during larval development in the spring or summer can drastically reduce the number of adult mosquitoes looking for a meal a week or two later.



https://www.smithsonianmag.com/science ... 434/?utm_source=onesignal

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