Sex on Six Legs_ Lessons on Life, Love, and Language From the Insect World - Marlene Zuk [84]
As my childhood flirtation with a career in myrmecology suggests, I am hardly immune to the drama of the ants' activities. But all of this symbolism, and the focus on aggression, runs the risk of seeing the ants as miniature soldiers instead of the skillful predators they are. What's really interesting about army ants isn't whether they show "incoherent and nerveless campaigns" as opposed to "sieges and investments as wisely ordered as our own." It's how and why that one virgin queen is singled out and sequestered from the rest in the colony. (Is she older? Younger? Or does one live and the others die at random? We still don't know.) It's how the colony's internal clock tells it when to migrate and when to make camp, given that research has shown the ants are not simply driven by hunger. Day length may give a proximate cue, while colony size also plays a role. It's how those massive colonies in Africa and South America differ from their less conspicuous counterparts in Texas or Alabama.
Army ants could even serve a more prosaic function, and one potentially useful to humans. Adrian Smith and Kevin Haight from Arizona State University pointed out that because other ant colonies tend to flee with their brood, evacuating the entire colony, queen and all, when army ants approach, researchers attempting to collect the prey species could exploit this behavior and save themselves time and trouble. They cheerfully—and in my opinion, just a tad cold-bloodedly—suggest that fellow scientists use a small batch of army ants to rout a desired species from their subterranean chambers, rather like tiny terriers sent after rabbits in a burrow, saving hours of often back-breaking labor excavating the nest. Their paper even includes links to videos that demonstrate, in eerily infomercial fashion, exactly how nifty and efficient this technique can be. It sounds like a great idea. But somehow "terrier ants" doesn't have much zing.
Adopting the Enemy
IF THE army ants are more hunters stocking their family larder than noble soldiers proving their mettle, what about the slave-making ants with their "wonderful" instinct, as noted by Darwin? The wars, or raids, that these ants undertake are not about getting food, at least not directly. A slave-maker colony is started when an inseminated queen of one species enters the nest of another, kills or expels the resident queen or queens, and begins to lay eggs of her own kind. Her children are then reared by the host species, which accepts them as if they were nest mates. To replenish the host workers, the slave-maker species sets out on periodic expeditions to snatch the larvae and pupae from another host colony, bearing them back to the slave-maker nest to mature and act as normal workers for their hosts. About fifty of the eleven thousand known ant species behave in this manner, with some capable of living on their own and others so specialized that they cannot even feed themselves without the help of their captives.
Despite their rarity, the slave-making ants have attracted a great deal of human attention. Charlotte Sleigh documents the fascination of nineteenth-century observers with the slave-making ants, many of whom were quite overt in their analogy with the human slave trade of the time. Perhaps surprisingly, many naturalists and authors decried, not the practice of exploiting the labor of others, but the "degeneracy" of the slave makers themselves. In characteristically opinionated prose, Maeterlinck disapprovingly notes that the slave makers "cannot eat without assistance, for they cannot take any nourishment save from the mouths of their servants. They are as little capable of rearing their young as of building or repairing their nest. In the depths of their lair they pass their time in besotted idleness, rousing themselves