I used to be scared of dragonflies -- they were big and buzzy and always zippin' their damn wings. Plus, the dragon part of their name was intimidating! Turns out though, dragonflies are really just a bunch of wussies. They can be scared to death.
A group of professors from the University of Toronto raised dragonfly larvae in tanks along with their predators (in this case, fish) to see how they would respond to fear. The dragonflies could see and smell their predators but remained separated from their predators. There was no danger! The fish couldn't eat the dragonfly. Locke Rowe, one of the professors conducting the research, said:
"What we found was unexpected-more of the dragonflies died when predators shared their habitat"
In fact, the dragonfly larvae exposed to their predators had survival rates 4 times less than larvae not exposed. Remember, these predators can't actually eat the dragonfly! The mere presence of predators scares them to death. In other experiments that tested juvenile dragonflies metamorphosising into adult dragonflies, 11 per cent of the dragonflies exposed to fish died (only 2 per cent of dragonflies not exposed died). Rowe noted:
"As we learn more about how animals respond to stressful conditions-whether it's the presence of predators or stresses from other natural or human-caused disruptions-we increasingly find that stress brings a greater risk of death, presumably from things such as infections that normally wouldn't kill them,"