Peatlands have a negative reputation that’s undeserved. For one thing, they store enormous amounts of CO₂. For another, they promote biodiversity. Over the centuries, many have been drained for peat extraction and to create farmland. Some peatlands are now being ‘restored’ through rewetting. But when the water returns, will mosquito populations explode? And will that also increase the chances of the transmission of diseases like dengue, malaria and Zika? In the Peene Valley wetlands in northeastern Germany, two scientists are investigating whether restored peatlands mean more mosquitoes. We go mosquito hunting with them and follow up in the lab where they also raise larvae. A system that only works with a steady supply of blood!