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."
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.
"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."