DFG-NSF Physics: Behavioral Repertoires in An Adaptive, Network-Building, Slime Mold

About This Grant

Slime molds have inspired and enabled a wide range of biotechnology and bioengineered applications. They are unusual organisms since as a single-celled organism they multinucleate, are capable of movement, memory-like behavior, decision-making, and efficient network formation. Biological highways built by the slime mold Physarum polycephalum experience similar goals and tradeoffs to human-built networks, including needing to efficiently allocate the matter the highways are built from, handling fluctuating levels of traffic, and resisting damage or outages. In building highways and its other behaviors, Physarum shows itself capable of intelligence and memory, while having no central organizing body and only limited ability to transmit information between different parts of the organism. Here, collaborating researchers at UCLA (USA) and TUM (Germany) will work to build experimental and theoretical models of Physarum’s ‘behavioral space’. The central hypothesis of this work is that slime mold highways can be reduced to finitely many modes. These modes are derived from physical constraints upon the long-range flows that can be created within the network as well as feedback between flows on the slime mold highways and the bio-motor driven pulsations of the network that create and shape them. The research team will map out Physarum’s behavioral space, relating the modeled flow modes to the biophysical processes that the slime mold uses to piece together its highways, including tube sprouting and pruning, and to the migration of the organism. Because of its size and the speed of its internal flows, Physarum contends with an extreme version of the physical challenges encountered by all single-celled organisms: how to allocate resources and coordinate behaviors across the entire cell. Work to understand its repertoire of intelligent behaviors will have expansive impacts on understanding of the extents to which cell behaviors emerge from biophysical constraints or from choices. Combined with the peculiar charisma of intelligent slime molds, the project creates a rich trove of broader impact activities. These include a workshop to fertilize discussions of multinucleate cell organization across organisms and ecosystems, and a joint US-German Research Experience for Undergraduates (REU) in which each year, three undergraduates from each country collaborate, make integral contributions to the project, and learn key physics skills. Additionally, the team will design and disseminate standards aligned lesson plans for K-12 students on maze-solving, to foster inquiry and curiosity about algorithms and information-use. This collaborative U.S.-German project is supported by the U.S. National Science Foundation (NSF) and the German Research Foundation (DFG), where NSF funds the U.S. investigator and DFG funds the partners in Germany. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.