Ecological and evolutionary consequences of localised predator-prey interactions

As predator-prey interactions result from behavioural processes, biased random walk models can be used to study foraging on a finer spatiotemporal scale. We developed a model to understand which cognitive abilities of predators (memory, perception) were most useful in various spatial prey patterns (pdf here). A central place forager alternates between random search, capturing prey, bringing it back to the nest, and homing to memorized profitable places (right-hand figure). We found that long memory was more useful in aggregated spatial patterns (as found before) but also that predators relying on perception were better in more random prey patterns. In turn, this implied the intake rate of 'memorizers' reacted more to prey spatial aggregation and that of 'perceivers' to prey density - while superefficient central place foragers with good memory and perception have a constant functional response (up to the point where prey is completely depleted).

In short, Holling's functional response model may not work so well for central place foragers knowing well their environment; use of memory tends to modify the relationship between intake and prey density. My conclusion from this is that most shapes of functional response are actually possible (so there's really no need to be dogmatic about any, and let as much as possible the available data inform choices in population/community dynamics models). Here's one other example of the many ways movement changes functional responses.