Adventures Among Ants - Mark W. Moffett [65]
The Allomerus constructions run continuously from one nest pouch to the next on different branches of their shrub and contain a highway of workers commuting from nest to nest. Other plant-dwelling ants erect similar covers over their trails, even with similar holes through which they come and go to forage. Such arcades probably serve primarily to protect the enclosed traffic against enemies (out of sight being out of mind), as do the trail covers of soil built by marauder ants and many driver ants.
Indeed, the Allomerus workers at my study site didn’t wait in ambush hour after hour at each “foxhole,” as would be expected if the structures were sit-and-wait traps; when conditions were calm, most of the holes were usually empty. But that wasn’t true at times of danger to the ants on the passageway within. After a day of pulling grasshoppers from my hair, I noticed interlopers of another ant, a species of Pheidole, or big-headed ant, climbing the plant to pin down a wounded grasshopper missed by the Allomerus. Upon the arrival of the Pheidole ants, the Allomerus workers began to guard each of the several dozen entrances to their arcade nearest the commotion caused by the intruders. These guards, aided by nestmates roaming the arcade surface, also caught and killed one Pheidole and carried it off.
Ants of many kinds will on occasion catch and kill enemies and prey along their trails, especially when workers are densely packed; it’s a matter of overwhelming the quarry, as army ants do, through staggering numbers, a tactic that can succeed even for a timid species if their legions are great enough. In this way the organization of a superorganism can be more responsive than the tissues in a body: trail-bound workers can shift seamlessly in their behavior from transport to protection to predation. It’s as if one’s liver could change function when the heart is incapacitated, and pump blood.
8 notes from underground
After a four-hour drive in a sedan taxi crammed with five other people, including Caspar Schöning, I emerged barely able to stand. The driver had dropped us off in front of a low building, the headquarters of Nigeria’s best-known national park, Cross River. There a young woman showed us to the office of the assistant director, who informed us that we would have to wait for the director before seeking our ants. After an hour in his waiting room, he ushered us into an expansive office, through a door labeled “S.O. Abdulsalam, Director, Esq.”
Caspar and I explained to Mr. Abdulsalam, whose large frame was wedged behind an expansive desk, that we had just spent two weeks at Gashaka-Gumti, where we found just one species of swarm-raiding driver ant, Dorylus rubellus. After two days in long-distance taxis, we had arrived at Cross River with hopes of finding a greater diversity of army ants. Having listened to us intently, Mr. Abdulsalam declared that collecting ants at Cross River was a laudable and serious endeavor. Meanwhile, his underlings among the park staff arrived one by one and filled chairs around a long table. The director of tourism, the director of security, the director of the environment, the director of education, the director of research, the director of things-that-go-bump-in-the-night—in the end there was a baker’s dozen of them, each putting on a dazzling smile for the boss.
Over the next hour the director of the directors proceeded to invite each man to demonstrate his rhetorical skills. Every one expressed his sincere belief in the Importance of Ant Research at Cross River, his surprise that no Ant Scientist had discovered the park before, and his general gratitude for our visit. The director interrupted occasionally to embellish a point, and when each had finished, he would sum up the speech we’d just heard, adding flourishes of his own that left no doubt as to who wore the oratorical crown. Somewhere along the line I managed to interject that, while we appreciated Mr. Abdulsalam’s generosity, it was getting late and we had