Ant shepherds, Home

A few evenings ago, when I was on nighttime natural history patrol, I noticed a gathering of ants along a branch of a White Pine. When I got my headlamp on the myrmecine congregation and looked very closely at the insects, I discovered that the ants weren't alone. Their company was an even larger group of aphids, those homopterans that make their living tapping into plant tissues and sucking their juices, sometimes to the point of considerable damage. At least a few ant species have learned how to take advantage of the situation by herding aphids and using the end point of the tapping process—a sweet liquid called "honeydew"—as a food source. The "dairy farmers" use tranquilizers emitted from their feet to keep their "cows" docile, and while the scene I captured this afternoon might look like predation, the ants are remarkably gentle with their herd members, moving them as required with the lightest of jaw touches and only, on occasion, eating an aphid or two.