Exploding insects (ants) were first described by Ulrich Maschwitz in 1974. The exploding ant, which is smaller than its rival ants, will grab a larger invader ant and rupture, gluing itself to its enemy. This is one means that exploding ants use to protect the colony.
Ants are not the only social insect capable of a “suicide explosion”. A similar phenomena occurs in the neotropical termite species, Neocapritermes taracua. A recent report in the journal, Science, describes a blue protein crystal present in older workers (You can see the blue crystals in the smaller workers just behind their head). When attacked by other soil-dwelling termite species, the blue workers burst, releasing a blue protein. Salivary secretions of the attacking termite activate the blue protein into a toxin that kills the attacker.
Only the oldest workers produce the blue protein. The oldest workers often have mandibles (mouthparts) that become worn- losing efficiency for foraging and processing food as they age. Adult workers cannot molt to another adult with shiny new mandibles. Their ability to contribute to the colony fades. They become old and in the way.
However, the old workers are still able to do battle to protect their colony. In addition to the production of the blue crystals, the older workers become more aggressive to intruders than the younger workers. An old worker with worn mandibles is not a match for most invaders. However, the exploding crystals on their back make them a lethal weapon. The crystals and defensive behavior by the oldest workers spare the youngest and healthiest workers from attack and destruction. The old are sacrificed so the young can attend to the feeding, care and other work of the colony.