The NewScientist weekly magazine had an article that made for some very interesting reading - Suicidal Termites spew toxic brew.

Old-aged termites go out with a bang, taking enemies with them. Jan Sobotnik from the Academy of Sciences of the Czech Republic and Thomas Bourguignon from the Free University of Brussels in Belgium were surprised to find pale blue spots on the abdomens of older termites (Neocapriterme taracua). But the real shock came when the pair picked up the insect - they exploded in their hands.

To investigate whether the suicides might be a part of a defence strategy, Sobotnik, Bourguignon and their colleagues pitted spotted and younger non-spotted termites against two rival species of termite that are known to compete with the other for land and food.

When the spotted termites were physically unable to defend themselves with their jaws, they would burst a pouch on their backs, releasing a liquid that paralysed and killed any termite it touched. Younger termites were less likely to self-detonate, and their liquid was far less toxic Science, DOI: 10.1126/science.1219129

The lethal brew is thought to be a mixture of the spots’ blue crystals and the insects’ saliva and haemolymph - a blood-like fluid.

The team thinks the insect develop their spotted toxicity to remain useful to the colony once they’re too old to forage for food.

Youtube video of the Neocapriterme taracua termite exploding