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Aging termites are great defenders--Study

A species of termite as it ages, has been found to cause more damage on its enemies.

When defending their colony, some termites "explode", releasing chemicals that injure intruders.
A previously unknown crystal structure has been discovered that raises the toxicity of their chemical weapons.

As worker termites age, they become less able to perform their duties but this newly discovered structure proves otherwise. On the contrary it proves that ageing workers are better defenders for their colony.

This twist in the tale has been discovered in a species from French Guiana.
"My PhD student, Thomas Bourguignon, was studying termite community ecology and collecting species when, casually, he found something really special," said Prof Yves Roisin from the Free University of Brussels.

When faced with a threat, many termite species employ a type of altruistic suicide known as "autothysis" in order to deter attackers. In a few species, workers join "soldier" termites in the defence of their colony and perform these acts of suicidal defence.

By rupturing their bodies, Neocapritermes taracua release a toxic chemical that sticks to intruders, holding them fast and corroding their bodies.

"Autothysis is usually a one component system. The defensive secretions are stored in salivary glands, but in these species there is a 'backpack' with two crystals carried outside the body. When the termite bursts, the two mix together, producing the more toxic compounds," Prof Roisin further explained.

The "backpacks" are formed from pouches on the outside of the body.
Although termite societies contain castes of "soldier" individuals with vastly enlarged mandibles that have evolved for the purpose of attacking intruders, workers can join fights and perform defensive suicides should the need arise.

The research shows that as they age, they store up crystals that produce a chemical reaction when mixed with glandular secretions. This increases the toxicity of their explosive defence mechanism.
Biologists believe it allows the ageing workers to become more "useful" to the colony as sacrificial, defensive bombs.

However, the process for crystal synthesis is not yet known, along with whether other species from the same genus has evolved a similar backpack system.

"There are some five or six species in the genus, but it's the only species that carries a backpack we've seen so far," Professor Yves Roisin said.

The research was published in the journal Science.