Mosquitoes are already nature’s most annoying parasites, but things just got worse. According to new research, their pain receptors go numb in extreme heat, making natural repellents like citronella and catnip oil about as effective as wishful thinking. As temperatures rise, these bloodsucking nightmares become even harder to deter.
Blame TRPA1, a receptor aptly nicknamed the “wasabi receptor” because it reacts to noxious stimuli. In humans, this little biological alarm bell makes spicy foods burn and chemical irritants sting. In mosquitoes, it usually helps them decide which targets to avoid—unless it’s too hot to care.
Peter Piermarini, entomologist at Ohio State University, explains that when temperatures soar past a certain threshold, TRPA1 stops responding properly. The result? Mosquitoes wade straight through their usual chemical deterrents like soldiers immune to tear gas. If your go-to defense is a spritz of citronella, summer just got significantly worse.
Typical repellents work by overwhelming mosquitoes’ senses, creating an invisible barrier of misery that keeps them at bay. But when their wasabi receptors tune out, natural repellents lose their punch. Catnip oil, usually a potent mosquito irritant, might as well be perfume in a heatwave.
“Products with those ingredients may be less effective if you’re using them at temperatures that are considered extreme heat events,” said Piermarini. Translation: If it’s scorching outside, you’d better hope mosquitoes have other plans. Spoiler: They don’t.
And let’s not forget the bigger problem—climate change. Rising temperatures mean longer mosquito breeding seasons, which means more disease-spreading, blood-stealing pests sticking around longer than they should. As if global warming didn’t already have enough consequences.
The study, published in *Pesticide Biochemistry and Physiology*, involved transplanting TRPA1 receptors from mosquitoes into frog egg cells. Because science. Researchers then doused the eggs with citronellal and catnip oil under different temperatures, observing how the receptors responded. Turns out, once the heat cranked up, the receptors barely reacted at all.
In a second experiment, they tested whether actual mosquitoes would behave the same way. Female mosquitoes—because only the females bite—were exposed to repellents in a controlled setting. At 32°C and beyond, they stopped avoiding the substances, confirming that summer is officially their time to thrive.
But there is some good news. DEET, the synthetic repellent many people already rely on, doesn’t interact with the wasabi receptor at all. That means its effectiveness remains unchanged, even when the heat is unbearable. If you plan to survive mosquito season, stick to the lab-designed stuff.
The takeaway? Nature is failing us, and mosquitoes are evolving into heat-resistant, pain-immune supervillains. Welcome to the future.
Did You Know?
- Mosquitoes are attracted to beer drinkers. Apparently, they prefer their blood with a hint of hops.
- Some species of mosquitoes hibernate, because even they need a break from being terrible.
- Dragonflies are the natural enemy of mosquitoes, with some species devouring hundreds per day. Time to start a dragonfly farm?
