Functional response

Abstract: These are my lecture notes from CS681: Design and Analysis of Algo rithms, a one-semester graduate course I taught at Cornell for three consec utive fall semesters from '88 to.

Abstract: A predator's per capita feeding rate on prey, or its functional response, provides a foundation for predator-prey theory. Since 1959, Holling's prey-dependent Type II functional response, a model that is a function of prey abundance only, has served as the basis for a large literature on predator-prey theory. We present statistical evidence from 19 predator-prey systems that three predator-dependent functional responses (Beddington- DeAngelis, Crowley-Martin, and Hassell-Varley), i.e., models that are functions of both prey and predator abundance because of predator interference, can provide better descrip- tions of predator feeding over a range of predator-prey abundances. No single functional response best describes all of the data sets. Given these functional forms, we suggest use of the Beddington-DeAngelis or Hassell-Varley model when predator feeding rate becomes independent of predator density at high prey density and use of the Crowley-Martin model when predator feeding rate is decreased by higher predator density even when prey density is high.

Abstract: Holling's Type II functional-response relationship is presented, and the formulations expressing the underlying organismal interactions which might generate such a relation arc generalized into the Type III response typical of predators showing learning behavior. An equation derived through an analogy with allosteric enzyme kinetics is given which will account for both Type II and Type III responses. The response behavior can be explained by three parameters: maximal feeding rate (F); an affinity constant (G) related to handling times, capture efficiencies, etc.; and the number of encounters (n) a predator must have with a prey item before becoming maximally efficient at utilizing the prey item as a resource. A discussion follows on the biological processes which result in shifts from Type II to Type III functional responses. Most of the learning processes involve changes in predator behavior associated with increasing encounters with prey, thus supporting parameter n as a major determinant in shifting th...