Fungi can measure wind speeds

The filamentous fungus Neurospora produces spores profusely on specialized stalk cells called aerial hyphae. The length of these cells is affected by a physical tradeoff: longer cells may see faster air speeds, but are also more likely to buckle under their own weight. In particular, best dispersal requires that aerial hyphae extend through the boundary layer of still air that clings to the parent fungus to reach the moving air flows beyond. Boundary layer thickness is controlled by wind speed, but how can wind speed be measured by the fungus’s microscopic cells? Our experiments growing fungi in wind tunnels show that aerial hyphae length varies to match boundary layer thicknesses. Further, we find that the cells’ ability to respond to changes in evaporation rates in the key to their microbial anemometry.