A certain species of termite, the neocapritermes taracua, likes to grow little blue "backpacks" as they age and wear out their welcome in the working world. The "backpacks" are filled with a toxic, sticky substance.
These "blue workers" have a tendency to rupture when grabbed by another termite, predator, or curious scientist with tweezers.
The blue spots on their back contain copper crystals which store proteins. When these pouches react with the termite's salivary gland secretions, they emit a droplet of toxic goo which is capable of paralyzing or even killing an enemy termite.
The termites that don't contain the blue crystals, the "white workers," are less aggressive and not as likely to get in on a fight. When scientist transplanted the blue crystal onto the white workers, they became more deadly.
Moral of the story: Don't go around poking termites with blue pouches on their back!
