The summer, the sunshine, the long-awaited vacation and the long evenings. Nothing in sight to disturb this blissful mood. Nothing…Really? Can’t you hear it, bzzzzzzzz… We all agree that we have no choice but to share our summer – and even spring and fall – days and nights with them: mosquitoes. They seem so content in the warmth of our homes… especially the striped one, Mister Tiger! Surely, climate change is to blame for all this. Here’s another thorny issue for us to clarify…
The invasion
First and foremost, let’s set things straight: has the number of mosquitoes really increased, or are we simply the victims of a cognitive bias linked to the fact that this tiny creature measuring just a fraction of an inch is most certainly the animal which, as Florence Foresti aptly puts it, “has the highest size-embarrassment ratio”.
No, it’s not a figment of your imagination: studies carried out by the Institut de Recherche pour le Développement (IRD) show that mosquito populations in Europe have increased significantly over the last few decades. Beyond the numerical growth, it is the proliferation of new species in our latitudes, previously confined to tropical and equatorial regions, that is cause for concern. According to data from Santé Publique France, the presence of Aedes albopictus – the tiger mosquito’s stage name – has risen from 2 departments in 2004 to 65 in 2020. What a fast mover.
Global warming: the culprit
Global warming is clearly a key factor in this territorial expansion. Mosquitoes are fond of heat and humidity. As temperatures rise, habitats suitable for these insects multiply, offering ideal conditions for their survival and reproduction, with faster cycles over longer periods. Changes in rainfall also play a crucial role. Mosquitoes need stagnant water to reproduce. More frequent and intense rainfall, as well as periods of drought followed by heavy precipitation, create the perfect setting for their development.
What impact?
What are the consequences of this proliferation, beyond itchy spots and sleepless nights spent chasing away the intruder?
The regional expansion of mosquitoes is raising major health concerns, as some species are responsible for the transmission of particularly dangerous diseases, such as the tiger mosquito, which carries the dengue, chikungunya and Zika viruses; or the anopheles, the main vector of malaria. A study by Oxford University reveals that the number of malaria cases in Africa could increase by 20% by 2050 due to global warming and the proliferation of this species. Health systems will have to adapt rapidly to cope with the emergence of these diseases in new regions.
A love-hate relationship
What can be done about this? Beyond fighting climate change, that goes without saying. Pulverize them? No way! Mosquitoes are essential for our biodiversity considering that they provide food to many species and contribute, alongside bees and butterflies, to pollination.
The challenge is rather to keep them at bay while respecting the whole living world. Natural repellents (citronella/lavender essential oils, etc.), mosquito nets, repellent plants (basil, mint, rosemary, etc.), elimination of stagnant water, mosquito traps… The emphasis must be placed on approaches respectful of our ecosystems.
Research is looking towards biological control methods, as this team of scientists who, in 2018, released tens of thousands of sterile tiger mosquitoes by drone into the Brazilian skies, in order to inseminate as many females as possible and render their eggs non-viable. Innovating to restore ancient balances… quite a concept.
Will humanity truly open its eyes to the urgency of action only when disturbed in its daily comfort? Now, it’s up to us to take each of our mosquito bites as a reminder of the fragility of our world…
1 J. Bouyer et al.Field performance of sterile male mosquitoes released from an uncrewed aerial vehicle.Sci. Robot.5,eaba6251(2020).DOI:10.1126/scirobotics.aba6251