Event

Motile organisms have developed strategies to move through natural environments, which are spatially complex and can fluctuate with time. Understanding the physics behind these strategies is important for bioinspired design – for instance, to build robots that move through rough and unpredictable terrain. I will discuss two (quite different!) broadly successful locomotive modes: flagellated motility in bacteria and interfacial locomotion in geckos. (1) A bacterium’s life is complicated: it interacts with different fluids, and may need to switch between swimming and surface attachment. Using magnetic tweezers to manipulate external torque on the flagellar apparatus, we characterized the mechanosensitive adaptation that facilitates these transitions. Our model for the dynamics of load-dependent assembly in the bacterial flagellar motor illustrates how this nanomachine allows bacteria to adapt to changes in their surroundings. (2) Animals that live in areas with periodic flooding must deal with seasonal fluctuations in their habitat. In the field, we showed that tropical geckos can run across the water’s surface as fast as they can on land. In the lab, we showed that these geckos use multiple modalities, including surface slapping and surface tension, and take advantage of their superhydrophobic skin, to transition between terrestrial and semi-aquatic locomotion.