Some mosquitoes have become increasingly reliant on human blood , new research shows – and it's probably our own fault. A sampling study of the bloodsuckers in Brazil has found that as biodiversity drops, mosquitoes are more likely to hunt us down . It makes sense, really: As human activity pushes other animals out of the region, mozzies have fewer alternatives to feast on. The consequences are more dire than just an itchy annoyance, though. Mosquitoes are key vectors of disease , so a shift in