The effects of invasive ants on prospective ant mutualists

*[Here, we review the effects of invasive ants on 3 guilds of mutualists: ant-dispersed plants, ant-tended arthropods, & ant-tended plants. We contrast how those 3 guilds are affected by invasions, how invasive ants differ from native ants in their interactions with those guilds, & how the 7 most invasive ant species differ amongst themselves in those interactions. Ant-dispersed plants typically suffer from interactions with invasive ants, a result we attribute to the small size of those ants, relative to native seed-dispersing ants. Effects on the ant-tended arthropods & plants were more frequently positive or non-significant, although it is unclear how often these interactions are reciprocally beneficial. For example, invasive ants frequently attack the natural enemies of these prospective mutualists even in the absence of rewards, & may attack those prospective mutualists. Many studies address whether invasive ants provide some benefit to the partner, but few have asked how invasives rank within a hierarchy of prospective mutualists, that includes other ant species. Because ant invasions typically result in the extirpation of native ants, this distinction is highly relevant to predicting & managing the effects of such invasions. Interspecific comparisons suggest that invasive ants are poorer partners of ant-dispersed plants than are most other ants, equally effective partners of ant-tended arthropods, and perhaps better partners of ant-tended plants. Last, we note that the invasive ant taxa differ amongst themselves in how they affect these 3 mutualist guilds, & in how frequently their interactions with prospective mutualists have been studied. The red imported fire ant, Solenopsis invicta, appears particularly likely to disrupt all 3 mutualistic interactions, relative to the other 6 invasive species included in this review.]