How a ‘backpack’ full of a toxic blue substance allows a termite to blow itself up, along with the threat, if its colony is threatened <\/p>
Just over a decade ago, scientists working in French Guiana\u00a0discovered<\/a>\u00a0a species of termite that carries a toxic blue substance contained in\u00a0explosive ‘backpacks’\u00a0which they detonate if the colony is under attack\u00a0\u2013\u00a0a form of self-sacrifice found elsewhere in the insect<\/a> world.<\/p> But for years, researchers were unable to establish how\u00a0Neocapritermes taracua<\/em>\u00a0does it. How can the termites safely carry around a dangerous chemical that will nevertheless explode when they need it to?<\/p> It turns out that the copper-containing blue crystals, known as laccase BP76, have a number of properties that keep them stable. An analysis of its crystal structure shows that it is tightly folded into a compact shape and that sugar molecules on the outside act as a protective shield. Two amino acids help to maintain BP76\u2019s structure.<\/p> Lead researcher on the study Jana Skerlova explains that to trigger the defensive mechanism, the termites must rupture their bodies by contracting the muscles between their body segments, thus allowing the BP76 to mix with labial secretions that dissolve the solid crystals.<\/p> \u201cThe reaction occurs instantly,\u201d\u00a0she says.\u00a0\u201cThere are no explosives as such, but the whole reaction is very fast and the toxic liquid bursts out from the termite\u2019s back, killing both the termite and the opponent.\u201d\u00a0<\/p> The ‘kamikaze’ behaviour of\u00a0N.\u00a0taracua\u00a0<\/em>(which can be watched in\u00a0this video<\/a>) is known as autothysis\u00a0\u2013\u00a0which literally means self-sacrifice\u00a0\u2013\u00a0and one of its many interesting aspects is the termites get better at it as they age.\u00a0<\/p> As the lead researcher, Robert Hanus, of the original study, published in\u00a0Nature<\/em>, said at the time:\u00a0\u201cOlder individuals are not as effective at foraging and nest maintenance as younger workers. In this moment, they can provide another service to the colony.\u201d<\/p> N. taracua<\/em>\u00a0is not the only termite<\/a> species to evolve autothystic behaviour. It has been reported in numerous other genera, and though the chemical nature of the substances varies as does the structure of the body parts that release them, the result is very similar.<\/p> \u201cIn all cases, the released substance is sticky and binds to predators, congealing when exposed to air and causing distress, immobility or death to the target,\u201d\u00a0reported scientists in\u00a0A review of self-destructive behaviour in social insects<\/a>. It is highly effective against other invertebrate predators but much less so against lizards or birds.<\/p>