Kamikaze termites carry ‘toxic rucksacks’ that explode to poison their enemies using hidden stash of blue crystals

TERMITES can explode themselves when attacked, spraying their adversaries with a blue poison that kills them in the process.

Now scientists have uncovered the secrets behind the mysterious substance, which the insects carry in a “backpack” and detonate at will.

Dr. Aleš Buček

Neocapritermes taracua termites carry a ‘backpack’ full of a blue enzyme and detonate it at will to defend the colony from attackers[/caption]

Researchers in the Czech Republic have obtained the first high-resolution image of the enzyme’s crystal structure, published August 15 in Structure.

The termite species in question, Neocapritermes taracua, is native to French Guiana.

And they are the only insects known to sacrifice themselves in such a manner – specifically, worker termites nearing the end of their lives.

In 2012, researchers learned that older workers carry blue spotted rucksacks that explode when attacked.

The bugs sport special glands in their abdomen that gradually secrete the enzyme blue laccase BP76 onto their back.

As they age, the termites accumulate the blue, copper-containing crystals.

When faced with a threat, they rupture their bodies, combining the enzyme with secretions from their salivary glands.

The resulting substance is rich in benzoquinones, which can paralyze or kill enemies.

Researchers were confused about how the enzyme could be stored as solid and turn to liquid upon detonation.

That is, until now. The Prague-based team produced the clearest images of the enzyme’s structure to date, showing how it is tightly folded like a piece of origami to keep from breaking down over time.

The protein is also linked to sugar molecules that form a stabilizing “shield.”

The scientists honed in on a peculiar chemical bond between two amino acids, lysine and cysteine, near the enzyme’s activation site.

This unusual bond is needed to maintain BP76’s structure, especially when carried around on a termite’s back.

This bond guarantees that the enzyme retains its shape, thus remaining fully functional and ready for use at any given moment.

Dr. Aleš Buček

Scientists took a closer look at the enzyme’s structure and discovered it is folded like paper to maintain its structure during transport[/caption]

R. Hanus

Worker termites accumulate the toxic blue crystals over time, giving them purpose as they become less effective at foraging and maintaining the nest[/caption]

Previous research suggests that older termites cannot search for food or maintain the nest as well as their younger counterparts.

Since the insects’ mandibles dull over time, the elderly workers are relegated to a different role – providing a final, selfless act to defend their colony.

“Just as knowledge about individual components of an instrument sheds light on how it works, knowing the three-dimensional structure of a molecule helps us understand a biological process,” co-author Pavlína Řezáčová said.

Termites aren’t the only insects that release benzoquinones when threatened.

Bombardier beetles spray the chemical compound at attackers, though they double down on the damage by excreting two different kinds.

One is derived from hydroquinone, used by humans as a skin-lightening agent, while another comes from m-cresol, a toxin found in coal tar.