Population Dynamics and Mutualism: Functional Responses of Benefits and Costs

We develop an approach for studying population dynamics resulting from mutualism by employing functional responses based on density‐dependent benefits and costs. These functional responses express how the population growth rate of a mutualist is modified by the density of its partner. We present sev...

Full description

Saved in:
Bibliographic Details
Published in:The American naturalist 2002-03, Vol.159 (3), p.231-244
Main Authors: Holland, J. Nathaniel, DeAngelis, Donald L., Bronstein, Judith L.
Format: Article
Language:English
Subjects:
Biology
Butterflies & moths
Cactus
Cost functions
Eggs
Evolution
Flowers & plants
Fruit abortion
Functional responses
Isoclines
Lophocereus schottii
Moths
Mutualism
Plants
Pollen
Pollination
Pyralidae
Upiga virescens
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We develop an approach for studying population dynamics resulting from mutualism by employing functional responses based on density‐dependent benefits and costs. These functional responses express how the population growth rate of a mutualist is modified by the density of its partner. We present several possible dependencies of gross benefits and costs, and hence net effects, to a mutualist as functions of the density of its partner. Net effects to mutualists are likely a monotonically saturating or unimodal function of the density of their partner. We show that fundamental differences in the growth, limitation, and dynamics of a population can occur when net effects to that population change linearly, unimodally, or in a saturating fashion. We use the mutualism between senita cactus and its pollinating seed‐eating moth as an example to show the influence of different benefit and cost functional responses on population dynamics and stability of mutualisms. We investigated two mechanisms that may alter this mutualism's functional responses: distribution of eggs among flowers and fruit abortion. Differences in how benefits and costs vary with density can alter the stability of this mutualism. In particular, fruit abortion may allow for a stable equilibrium where none could otherwise exist.
ISSN:0003-0147
1537-5323
DOI:10.1086/338510