title: Macroevolutionary patterns in the origin of mutualisms involving ants.
abstract: Ants are a diverse and abundant insect group that form mutualistic associations with a number of different organisms from fungi to insects and plants. Here, we use a phylogenetic approach to identify ecological factors that explain macroevolutionary trends in the mutualism between ants and honeydew-producing Homoptera. We also consider association between ant-Homoptera, ant-fungi and ant-plant mutualisms. Homoptera-tending ants are more likely to be forest dwelling, polygynous, ecologically dominant and arboreal nesting with large colonies of 10(4)-10(5) individuals. Mutualistic ants (including those that garden fungi and inhabit ant-plants) are found in under half of the formicid subfamilies. At the genus level, however, we find a negative association between ant-Homoptera and ant-fungi mutualisms, whereas there is a positive association between ant-Homoptera and ant-plant mutualisms. We suggest that species can only specialize in multiple mutualisms simultaneously when there is no trade-off in requirements from the different partners and no redundancy of rewards.
authors.affiliation: Centre for Ecology and Hydrology, Biological Records Centre, Wallingford, Oxfordshire, UK. toliver@ceh.ac.uk
authors.forename: T H
authors.initials: TH
authors.lastname: Oliver
authors.forename: S R
authors.initials: SR
authors.lastname: Leather
authors.forename: J M
authors.initials: JM
authors.lastname: Cook