Urbanization drives partner switching and loss of mutualism in an ant-plant symbiosis

Mutualistic interactions between species underpin biodiversity and ecosystem function, but may be lost when partners respond differently to abiotic conditions. Except for a few prominent examples, effects of global anthropogenic change on mutualisms are poorly understood. Here we assess the effects of urbanization on a symbiosis in which the plant Cordia nodosa houses ants in hollow structures (domatia) in exchange for defense against herbivores. We expected to find that mutualist ants would be replaced in the city by heat-tolerant opportunists, leaving urban plants vulnerable to herbivory. In five protected forest sites and five urban forest fragments in southeast Perú, we recorded the identity and heat tolerance (CTmax) of ant residents of C. nodosa. We also assayed their plant-defensive behaviors and their effects on herbivory. We characterized the urban heat-island effect in ambient temperatures and within domatia. Forest plants housed a consistent ant community dominated by three s..., Methods are detailed in the main manuscript., , # Urbanization drives partner switching and mutualism breakdown in an ant-plant symbiosis

This dataset includes eight files that document differences between urban and forest sites in the symbiotic interaction between Cordia nodosa plants and ants that live within the plants' domatia. Files are listed below, along with a description of the data included in each column.

## Description of the data and file structure

| file name | column header | explanation |
| :---------------------- | :-------------------------------------------------------------------------------------------------------...