Aging termites put on suicide backpacks full of chemical weapons
Termite workers don’t get to peacefully retire. As they age and their bodies can work no more, some of them are fitted with suicide backpacks and conscripted for war.
There are thousands of termite species, and many engage in chemical warfare. Some squirt noxious chemicals from nozzles on their heads. Others violently rupture their own bodies to release sticky immobilising fluids, sacrificing themselves for the good of their sisters. Their range of weapons is astounding, and Jan Sobotnik from the Academy of Sciences of the Czech Republic and Thomas Bourguignon from the Université Libre de Bruxelles have just found a new one.
They were studying the termite Neocapritermes taracua when he noticed that some workers have a pair of dark blue spots in the gap between their torsos and abdomens. When other termites attack their colony, the blue workers bite the intruders and burst, releasing a drop of fluid that soon becomes sticky gel. Watch it happen in the video below – the black dot in the middle of the droplet are intestines and other internal organs).
The blue colour comes from crystals, secreted by a pair of glands at the base of the termites’ torsos. The fluid is deadly to other termites. When Sobotnik and Bourguignon dabbed the fluid on a competing termite species, 28 per cent were paralysed and 65 per cent died. If he removed the blue crystals, the fluids were far less lethal. Conversely, if he added the crystals to white workers, they became toxic (but not as toxic as the blue ones).
The team think that the termites use a two-part weapon. The blue crystals are the first part. They contain a protein with copper atoms, which explains why they’re blue. The protein is a haemocyanin, which carries oxygen around the blood of insects just as haemoglobin does in our blood stream.
The second part comes from the salivary glands, which, oddly enough, are found in the termite’s back rather than its head. Bourguignon thinks that when the termite bursts, the coppery protein transforms otherwise harmless compounds in the salivary glands, and turns them toxic. “The toxicity of the blue workers is clearly the result of mixing compounds from two sources,” he says.
Sobotnik and Bourguignon found that this suicidal strategy is only used by older workers. Over time, their mandibles wear out and they can’t carry out the menial tasks that they performed in their youth. And as their mandibles become blunt, the blue crystals in their backs get larger. Compared to the younger white workers, the blue ones were more aggressive towards other termites, and exploded much earlier.
Quoting E. O. Wilson, the duo writes, “We send our young men to war; ants send their old ladies.” The same could be said of termites.
Reference: Sobotnik, Bourguignon, Hanus, Demianova, Pytelkova, Mares, Foltynova, Preisler, Cvacka, Krasulova & Roisin. 2012. Explosive Backpacks in Old Termite Workers. Science http://dx.doi.org/10.1126/science.1219129
Image by R. Hanus
More on insect defences:
- The bees that mummify beetles alive
- Assassin bugs deceive spiders with coat of many corpses
- Suicidal menopausal aphids save their colony by sticking themselves to predators
- Suicidal menopausal aphids save their colony by sticking themselves to predators
- Bees kill hornets with carbon dioxide emissions and local warming
- Aphids defend themselves with chemical bombs
- Aphids hide from parasitic wasps among the corpses of their peers
- Caterpillars use wormholes and early warning hairs for defence
- Giant bees do Mexican waves to ward off wasps
- Leaf beetle protects itself with a mobile home made of faeces
Go Further
Animals
- This ‘saber-toothed’ salmon wasn’t quite what we thoughtThis ‘saber-toothed’ salmon wasn’t quite what we thought
- Why this rhino-zebra friendship makes perfect senseWhy this rhino-zebra friendship makes perfect sense
- When did bioluminescence evolve? It’s older than we thought.When did bioluminescence evolve? It’s older than we thought.
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
Environment
- This pristine piece of the Amazon shows nature’s resilienceThis pristine piece of the Amazon shows nature’s resilience
- Listen to 30 years of climate change transformed into haunting musicListen to 30 years of climate change transformed into haunting music
- This ancient society tried to stop El Niño—with child sacrificeThis ancient society tried to stop El Niño—with child sacrifice
- U.S. plans to clean its drinking water. What does that mean?U.S. plans to clean its drinking water. What does that mean?
History & Culture
- Séances at the White House? Why these first ladies turned to the occultSéances at the White House? Why these first ladies turned to the occult
- Gambling is everywhere now. When is that a problem?Gambling is everywhere now. When is that a problem?
- Beauty is pain—at least it was in 17th-century SpainBeauty is pain—at least it was in 17th-century Spain
- The real spies who inspired ‘The Ministry of Ungentlemanly Warfare’The real spies who inspired ‘The Ministry of Ungentlemanly Warfare’
- Heard of Zoroastrianism? The religion still has fervent followersHeard of Zoroastrianism? The religion still has fervent followers
Science
- Here's how astronomers found one of the rarest phenomenons in spaceHere's how astronomers found one of the rarest phenomenons in space
- Not an extrovert or introvert? There’s a word for that.Not an extrovert or introvert? There’s a word for that.
- NASA has a plan to clean up space junk—but is going green enough?NASA has a plan to clean up space junk—but is going green enough?
- Soy, skim … spider. Are any of these technically milk?Soy, skim … spider. Are any of these technically milk?
- Can aspirin help protect against colorectal cancers?Can aspirin help protect against colorectal cancers?
Travel
- What it's like to hike the Camino del Mayab in MexicoWhat it's like to hike the Camino del Mayab in Mexico
- Is this small English town Yorkshire's culinary capital?Is this small English town Yorkshire's culinary capital?
- Follow in the footsteps of Robin Hood in Sherwood ForestFollow in the footsteps of Robin Hood in Sherwood Forest
- This chef is taking Indian cuisine in a bold new directionThis chef is taking Indian cuisine in a bold new direction