Some older/less efficient worker termites will develop 'backpacks' of toxic chemicals that explode when the termite is threatened. They are essentially used as suicide bombers when the colony is being attacked.
8
Mosquitoes don't just bite you, they also pee on you.
11
Moths are unable to fly during an earthquake.
328
The pea aphid insect explodes itself thereby sacrificing its life to protect its relatives from predators.
3