Joint evolution of predator body size and prey-size preference

Abstract

We studied the joint evolution of predator body size and prey-size preference based on dynamic energy budget theory. The predators' demography and their functional response are based on general eco-physiological principles involving the size of both predator and prey. While our model can account for qualitatively different predator types by adjusting parameter values, we mainly focused on 'true' predators that kill their prey. The resulting model explains various empirical observations, such as the triangular distribution of predator-prey size combinations, the island rule, and the difference in predator-prey size ratios between filter feeders and raptorial feeders. The model also reveals key factors for the evolution of predator-prey size ratios. Capture mechanisms turned out to have a large effect on this ratio, while prey-size availability and competition for resources only help explain variation in predator size, not variation in predator-prey size ratio. Predation among predators is identified as an important factor for deviations from the optimal predator-prey size ratio.

A biomechanical and optimality-based derivation of prey-size dependencies in planktonic prey selection and ingestion rates

“…Dependence of ingestion rate on prey size is described by the feeding kernel function, which is generally a unimodal function that determines the edible part of the preysize spectrum that is grazed and the corresponding rate at which grazing can occur. Both the functional form of feeding kernels and the implied diet breadth affect the results of size-based foraging models; kernel shape controls the transfer of mass and energy within model food webs, affects food web stability, and influences the extent of coexistence among (model) species (Troost et al 2008, Fuchs & Franks 2010.…”

“…Spectral or multi-species size-based models use explicit or implicit assumptions on the shape of the feeding kernel. Modeling either starts from empirical rules-of-thumb (Maury et al 2007, Petchey et al 2008, Williams et al 2010 or from kernel shape functions, such as Gaussian (Armstrong 2003, Troost et al 2008, Banas 2011 or Laplacian functions (Fuchs & Franks 2010), which until now lack thorough empirical testing and mechanistic explanations. Only recently, Visser & Fiksen (2013) proposed re-routing size-based feeding models towards biomechanical and evolutionarily sound principles, and assembled process-oriented formulations such as prey size dependencies of capture probability or energy content per item.…”

Bifurcation theory, adaptive dynamics and dynamic energy budget-structured populations of iteroparous species

“…The invasion fitness is computed by two-population competition simulations. This approach is more universal and can be used for a wide range of population models and also when the ecological and evolutionary time scales are not separated (see also Troost et al 2008). However, the accuracy of the simulation can be problematic and the calculations are much more time-consuming.…”

How trophic interaction strength depends on traits

“…Consider, for example, the (logarithmic) predator-prey body-mass ratio (PPMR), that is, the difference between logarithmic body masses of consumers and their resources log M c − log M r , which has been shown to be a good predictor of trophic interactions (Brose et al 2006). While trophic interactions are generally more likely to occur within a certain intermediate range of the PPMR (Otto et al 2007;Troost et al 2008), the prey-size preference of a predator is not determined by its body size alone (Jennings et al 2002), but it also depends on its mode of foraging, the shape of its ingestive organ, and many other characteristics. Usually, the corresponding term in Eq.…”