What price, no more mosquitoes? Xinhua News Agency/REX Shutterstock

A race is on to do something about the Zika virus. A possible vaccine is years away, so that means doing something about its vector, the Aedes aegypti mosquito.

Genetic engineering techniques mean it is possible to conceive of obliterating this insect entirely. But would there be an ecological downside to exterminating a creature whose only purpose seems to be to bother us?

As with many predictions involving complex natural systems, a definitive answer is impossible. Some ecologists worry about small changes having big unforeseen effects, and liken the …