MicrobeWorld

A study in the September issue of The American Naturalist describes new details about a fungal parasite that coerces ants into dying in just the right spot—one that is ideal for the fungus to grow and reproduce. The study, led David P. Hughes of Harvard University, shows just how precisely the fungus manipulates the behavior of its hapless hosts. When a carpenter ant is infected by a fungus known as Ophiocordyceps unilateralis, the victim remains alive for a short time. The fungus, however, is firmly in the driver's seat. It compels the ant to climb from its nest high in the forest canopy down into small plants and saplings in the understory vegetation. The ant then climbs out onto the underside of a low-hanging leaf where it clamps down with its mandibles just before it dies. There it remains, stuck fast for weeks.