Planktonic encounter rates with non-spherical encounter zones

Thursday 01 Aug 19


Anders Peter Andersen
Associate Professor
DTU Physics
+45 45 25 33 12

A new theoretical approach makes it possible to model planktonic predator-prey interactions and quantify the effects of the encounter zone shape for both non-motile and motile predators.

Encounter rates are key in mechanistic descriptions of interactions between individual organisms. In a new paper, we model encounter problems with highly non-spherical encounter zones, e.g., slender prey capture structures of microorganisms or cone-shaped encounter zones of visual predators. Our approach allows us to derive easily applicable formulas for both non-motile and moving encounter zones and to explore the effects of their shape. We present two main quantitative predictions for ballistic predator-prey interactions. When the predator is non-motile, the encounter rate is independent of the shape of the encounter zone and proportional to the product of the surface area of the encounter zone and the prey speed. In contrast, we find that the shape of the encounter zone can significantly influence the encounter rate when both the predator and the prey are moving and we quantify the effect. Our approach is applicable to predator-prey encounter problems with aquatic organisms across size-classes from unicellular microorganisms to fish.

Contact: Julia Dölger, Postdoctoral Associate, Massachusetts Institute of Technology,

Read the paper here

Anders Andersen and Julia Dölger, Planktonic encounter rates with non-spherical encounter zones, Journal of The Royal Society Interface 16, 20190398 (2019).