Maybe We've Been Fighting the Wrong Enemy

For years, we've battled mosquitoes — using DDT, DEET, bed nets, even sterile mosquitoes bred not to reproduce. Now, UC Davis entomology professor Geoff Attardo thinks we've been approaching it wrong. The real issue, he says, isn't the mosquito — it's how we've changed our wetlands, making it easier for them to thrive.

Dead vegetation, fertilizer runoff, and stagnant water create the perfect mosquito nursery — thick with algae and bacteria, low on oxygen. That doesn't slow larvae down, though, because they don't depend on oxygen in the water.

"They have siphons that basically are breathing through their butts,” says Attardo.

In a degraded environment, mosquitoes multiply fast — nothing's around to eat them.

California has lost 95% of its wetlands over the past two centuries. Recent studies show communities living near the remaining healthy wetlands see fewer mosquito-borne diseases like dengue.

But Attardo says, "When I go to healthy wetland ecosystems, it's actually hard for me to find mosquito larvae."

In healthy wetlands, living plants pump out oxygen and soak up nutrients, so algae and bacteria can't take over. Fish and other predators eat larvae before they mature — and with more animals around, mosquitoes have plenty else to bite besides us. Because so few larvae normally survive predators and competition, mosquitoes evolved to lay huge numbers of eggs as insurance.

"Because the odds of survival are very low. But when you take away those pressures, those reproductive adaptations just explode, kind of exponentially, because you've removed the pressure valve that is normally keeping them in check."

None of this is new, says Attardo. History keeps teaching us the same lesson.

"Everybody thinks the mosquitoes are the problem, but when you look back in history, all these diseases have come from basically major human disturbances."

Take the Panama Canal. In the 1880s, French engineers began digging, tearing up land and leaving standing water everywhere. Mosquitoes thrived. Yellow fever and malaria tore through the workforce and helped sink the effort. It took years and a better understanding of mosquitoes before outbreaks were finally brought under control.

And mosquito-borne disease doesn't spread evenly. It follows inequality, often hitting hardest in communities near degraded, poorly managed waterways.

"These diseases thrive in poor and underserved places because the broken-down infrastructure and lack of education and other things just allow these diseases to bloom,” says Attardo.

Mosquitoes don't recognize zip codes. Eventually, they spread out from neglected areas.

So maybe it's time for a different question. We've long asked how to better kill mosquitoes. Maybe we should also ask why we've built a world where they thrive.

High-tech fixes — genetic engineering, chemical spraying — are expensive and infrastructure-heavy. Ecological solutions can be simpler, cheaper, and rooted in Indigenous knowledge that already knew how to keep landscapes and people healthy.

Bring back the wetlands. We might just fix the mosquito problem, too.

— Dr. Michael Wilkes with a Second Opinion

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