2015/01/02 by Stephen J. Helms, Helms, Stephen J., W. Mathijs Rozemuller +10
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Genetics, Aging, and Longevity in Model Organisms #Advanced Thermodynamics and Statistical Mechanics #Evolution and Genetic Dynamics
paper · pdf · doi:10.48550/arxiv.1501.00481
A quantitative understanding of organism-level behavior requires predictive\nmodels that can capture the richness of behavioral phenotypes, yet are simple\nenough to connect with underlying mechanistic processes. Here we investigate\nthe motile behavior of nematodes at the level of their translational motion on\nsurfaces driven by undulatory propulsion. We broadly sample the nematode\nbehavioral repertoire by measuring motile trajectories of the canonical lab\nstrain C. elegans N2 as well as wild strains and distant species. We focus on\ntrajectory dynamics over timescales spanning the transition from ballistic\n(straight) to diffusive (random) movement and find that salient features of the\nmotility statistics are captured by a random walk model with independent\ndynamics in the speed, bearing and reversal events. We show that the model\nparameters vary among species in a correlated, low-dimensional manner\nsuggestive of a common mode of behavioral control and a trade-off between\nexploration and exploitation. The distribution of phenotypes along this primary\nmode of variation reveals that not only the mean but also the variance varies\nconsiderably across strains, suggesting that these nematode lineages employ\ncontrasting ``bet-hedging'' strategies for foraging.\n