Terrorism doesn't just exist among humans, according to ecologist Mark Moffett, and he has the photos to prove it.
In his new book "Adventures Among Ants" (University of California Press, 2010), Moffett describes — and shows — how some ants will commit suicide in a very dramatic way while taking others out with them. (See "Poison-Taster Ants Help Save Colonies.")
Moffett told me that in this photo, "the reddish worker cylindricus ant has detonated — rupturing her body to release a toxic yellow glue that kills her and the enemy instantly."
Just before this picture was snapped in Borneo, Moffett had set a trap at the base of a tree colonized by cylindricus ants. The trap was simply some honey that he drizzled around the tree trunk.
He describes what happened next:
"After an hour, weaver ants along with another species of carpenter ant located the bait and started arriving at the cylindricus-occupied tree. One of them started up the trunk, but then came down again. That one would live another day. Another climbed a bit higher and attempted to walk by a cylindricus minor worker. Just as I clicked the shutter there was a splash of yellow, and both ants were immobilized in a sticky, grotesque tableau." (Test your ant smarts: Take this quiz.)
In his book, Moffett describes yet another species of cylindricus ant that includes "living doors." The major worker's head flattens into a disc, he explains, "enabling her to serve as a living door to nests in hollow branches. She allows her nestmates inside only after they identify themselves by tapping the blockading disc with their antennae." (See: "Tiny Insect Brains Solve Big Problems.")
When he tried to grab a minor worker that was climbing the tree trunk, an additional protective measure took place. He said the "ant's leg fell away in my hand, in much the way that a lizard will lose its tail."
Moffett also describes a Brazilian species, Forelius pusillus, that kills entire ant nests at a time.
"Up to eight sacrificial individuals stay outside at night to seal the entrance with sand, kicking the final grains in place until no trace of the hole is visible. Walled off from their sisters, by dawn almost all are dead, for reasons unknown—perhaps the squad consists of the old or sick. The ants in the nest then clear the passage to begin the day’s foraging. That night, more victims seal the door."
To understand such behavior, Moffett suggests that we think of an ant colony like a single organism. Cutting off a "minor" part may help to save the colony as a whole. "The larger the colony, the less consequential the casualty," he said. (See: "Insects actively surf the wind.")
"Such extremism in handling risk is an example of how death without reproduction can be of service to queen and colony, and a reminder that anything humans concoct — even suicide missions and terrorism — probably has a parallel in nature."
Could it be that the ever-ballooning human population means more terrorism and warfare are in our future?
No one knows for certain, but as Moffett ominously points out, the bigger a population becomes, the more it can take large-scale risks, "given that losing 10 percent of an army will be more devastating for a society of ten than for one of a million."