Tiny flea reveals the devastating costs of invasive species

Humans have played a key role in moving species to new locations, resulting in an exponential spread of species over the last century. Many of these nonnative species never become invasive – that is, damaging – and a few may even have positive effects on ecology or human economy. However, many, such as Asian carp in North American rivers and Burmese pythons in the Florida Everglades, cause enormous ecological and economic damage.