Mechanics of the artillery fungus

Abstract

Species of artillery fungus, Sphaerobolus, use a unique, snap-through buckling mechanism to discharge their spores over a longer distance than any other known fungi. Here, we provide new information on biomechanics of glebal discharge by capturing the launch using high-speed video, measuring the force generated by the inner cup that expels the gleba, and modeling the relationship between the force and speed of the gleba to its trajectory. Associated calculations reveal that patches of the artillery fungus consume 80 times more energy than an individual gilled mushroom to release the same number of spores. The evolution of this costly mechanism may be counterbalanced by the relatively low wastage of spores carried in its sporangia compared with the greater losses of spores released from conventional mushrooms.

Keywords: Basidiomycetes; Fruit bodies; Latch-mediated spring actuation; Snap-through buckling; Spores.