On a late October morning in a hilly, middle-class neighbourhood in central Singapore, a crowd was forming for a surprising event. Top government officials, community leaders and a throng of media with cameras gathered around a group of scientists who had brought a most unusual gift: boxes of mosquitoes.

With a shout of “one, two, three”, they opened the boxes and released 3,000 of the insects into the air above Singapore’s Braddell Heights. In a country where the warm, tropical climate is ideal for mosquitoes, most people are used to swatting the insects rather than releasing more of them into the environment.

Fortunately, the residents of Braddell Heights had been prepared months in advance for this event, and welcomed the release. They knew that the mosquitoes would not bite – and that they were participating in an important study on the impact of mosquitoes infected with Wolbachia, a bacterium that hinders the insects’ fertility and blocks the ability of viruses like Zika to spread.

Singapore isn’t the only country throwing mosquitoes into the air. Across Asia and Latin America, scientists are trying out radical new methods to defeat Aedes aegypti, and the less widespread Aedes albopictus – the mosquito species that spreads the dengue, chikungunya, and Zika viruses.