Summary: Ecological Modelling 191 (2006) 551­556
Short communication
Emergence of ratio-dependent and predator-dependent
functional responses for pollination mutualism
and seed parasitism
Donald L. DeAngelisa,, J. Nathaniel Hollandb
a U.S. Geological Survey, Florida Integrated Science Centers, and Department of Biology,
University of Miami, Coral Gables, FL 33124, USA
b Department of Ecology and Evolutionary Biology, MS-170, Rice University, Houston, TX 77005, USA
Received 5 January 2004; received in revised form 10 June 2005; accepted 20 June 2005
Available online 1 August 2005
Abstract
Prey (N) dependence [g(N)], predator (P) dependence [g(P) or g(N,P)], and ratio dependence [f(P/N)] are often seen as con-
trasting forms of the predator's functional response describing predator consumption rates on prey resources in predator­prey
and parasitoid­host interactions. Analogously, prey-, predator-, and ratio-dependent functional responses are apparently alterna-
tive functional responses for other types of consumer­resource interactions. These include, for example, the fraction of flowers
pollinated or seeds parasitized in pollination (pre-dispersal) seed-parasitism mutualisms, such as those between fig wasps and
fig trees or yucca moths and yucca plants. Here we examine the appropriate functional responses for how the fraction of flowers
pollinated and seeds parasitized vary with the density of pollinators (predator dependence) or the ratio of pollinator and flower
densities (ratio dependence). We show that both types of functional responses can emerge from minor, but biologically important

Source: Azevedo, Ricardo - Department of Biology and Biochemistry, University of Houston
Holland, J. Nathaniel - Department of Ecology and Evolutionary Biology, Rice University

Collections: Biology and Medicine; Environmental Sciences and Ecology