Adaptive locomotion of living organisms contributes to their
competitive abilities and helps maintain their fitness in diverse
environments. To date, however, our understanding of searching behavior
and its ultimate cause remains poorly understood in ecology and biology.
Here, we investigate motion patterns of biofilm-inhabiting marine raphid
diatom Navicula arenaria var. rostellata in
two-dimensional space. We report that individual Navicula cells
display a “circular run-and-reversal” movement behavior at different
concentrations of dissolved silicic acid (dSi). We show that gliding
motions of cells can be predicted accurately with a universal Langevin
model. Our experimental results are consistent with an optimal foraging
strategy and a maximized diffusivity of the theoretical outcomes in
which both circular-run and reversal behaviors are important
ingredients. Our theoretical results suggest that the evolving movement
behaviors of diatoms may be driven by optimization of searching
behavioral strategy, and predicted behavioral parameters coincide with
the experimental observations. These optimized movement behaviors are an
evolutionarily stable strategy to cope with environmental complexity.
ONE SENTENCE SUMMARY :
Novel experiments and modelling
reveal that raphid diatoms can actively exploit resources in complex
environments by adjusting their movement behavior.