Older worker termites of Neocapritermes taracua (top right and bottom right) develop blue pouches that can explode to harm their enemies. The yellow-headed termite is a soldier.
Termites Explode to Defend Their Colonies
Author: Zoe Cormier
A species of termite found in the rainforests of French Guiana takes altruism seriously: aged workers grow sacks of toxic blue liquid that they explode onto their enemies in an act of suicidal self-sacrifice to help their colonies (see video
The “explosive backpacks” of Neocapritermes taracua, described in Science today1, grow throughout the lifetimes of the worker termites, filling with blue crystals secreted by a pair of glands on the insects' abdomens. Older workers carry the largest and most toxic backpacks. Those individuals also, not coincidentally, are the least able to forage and tend for the colony: their mandibles become dull and worn as the termites age, because they cannot be sharpened by moulting.
Read more at Nature.