Entomology behind

mosquito population control

By Julien Baylet

Summary :

This document explains some of the important steps to follow when identifying mosquito species and some of the strategies used during larvicide treatment operations.

How does a mosquito work?

Mosquitos are insects that completely morph during their developmental stages. They go through 4 different stages; egg, larva, nymph and adult. Each species has specific capacities to exploit specific habitats during precise periods of time. They are also influenced, as all insects are, by temperature as they are poikilotherms (cold blooded animals).

When inside their egg, mosquitos are either in diapause or are developing depending on outside temperature and photoperiod.

They then hatch and become larvae and eat as much as they can. Some species are herbivores while others are bigger and are carnivores. Their exoskeletons are non-extensible and they will molt in order to grow. During that process, they will leave behind an exuvium that can be used for later identification as it conserves hairs and body proportions.

The nymph stage is the moment when larvae transform completely and morph into an adult. During this period, they are vulnerable to predators as they are unable to move as fast and defend themselves. It is important to note that nymph and pupa are very similar terms that are usually interchanged but there is a difference between both of them. The pupa designates the exoskeleton surrounding the larva. When moulting, the larva detaches from its exoskeleton to morph into an adult, during this stage it can still move around in water and is considered a nymph.

Anti-mosquito treatments

During our anti-mosquito treatments, most mosquitoes will be regulated using Bacillus thuringiensis (israelensis), a type of bacteria used in the composition of a biologic larvicide that can be bought in most gardening supply stores. This particular larvicide has been in use in Quebec since the end of the XXth century and is regularly tested by the MDDELCC, the Ministère du Développement Durable et de la Lutte contre les Changements Climatiques. The purpose of these controls is to create a follow-up on the accumulation of bacteria and adjuvants used in the creation of the different versions of the larvicide and its impact on the surrounding environment. After several studies, it has been confirmed scientifically that the use of Bti is much more ecofriendly than other alternatives that use toxic chemical compounds that languish in the treated environment for several decades, sometimes several centuries. These long-term effects can be the source of future health concerns for the ecosystem and humans inhabiting the area. It is important to note that Bti can have an effect on some specific microorganisms but that globally, the negative effects are minimal when spreading operations are handled properly.


CFR states that it has never nor will it ever use chemically damaging larvicides.

For more information on biological treatment: Biological Control of Biting Insects.
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Publication date: November 27, 2015

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