Objects within a few millimeters cause the fruiting body of Phycomyces to bend away without ever making contact. Regardless of the object—opaque or transparent, smooth or rough—Phycomyces starts to bend away after about two minutes. Electrostatic fields, humidity, mechanical cues, and temperature have all been ruled out. Some hypothesize that Phycomyces uses a volatile chemical signal that deflects around the obstacle with tiny air currents, but this is far from proven.
