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.
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."
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.
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."