Picaridin-containing repellents are used by humans to repel insects, and may end up in aquatic ecosystems. The picaridin-containing repellent we tested did not directly affect mosquito larvae survival or development, but trace concentrations of it caused substantial mortality of larval salamanders under laboratory conditions. We hypothesize that a loss of predators may in turn increase the emergence of mosquitos in impacted ecosystems, which can possibly trigger increased application of picaridin repellent and thus lead to a positive feedback loop. (Online version in colour.)

1 of the only 2 pictures is about how this happens...

You really should have been able to see that if you clicked the link.