title: Mutualisms: Assessing the benefits to hosts and visitors.
abstract: A great number and variety of interactions are widely assumed to be mutualistic because the species involved exchange goods or services from which they appear to derive benefit. A familiar example is pollination, in which animal vectors receive food in the form of nectar and/or pollen, while the ovules of plants are fertilized. Unfortunately, most studies fail to demonstrate that both participants benefit in any significant way and therefore lack the information necessary to determine whether a given interaction is mutualistic. While mutualism is thought to be a common type of species interaction, there is still little evidence for this belief.
authors.affiliation: Hall Cushman and Andrew Beattie are at the School of Biological Sciences, Macquarie University, Sydney, NSW 2109, Australia.
authors.forename: J H
authors.initials: JH
authors.lastname: Cushman
authors.forename: A J
authors.initials: AJ
authors.lastname: Beattie