Western Yellowjacket Vespula pensylvanica

This North American wasp has a dark population secret: it absolutely thrives in warm weather. Without cold winters to control their numbers, populations can explode exponentially—which is exactly what happened when they invaded the Hawaiian Islands, becoming a major pest.

The irony cuts deep: in their native northern ranges, winter naturally resets populations each year, keeping them manageable. But transplant them to a warm, endless climate, and they become an ecological nightmare with nothing to stop their exponential growth.