<b>Ant-plant mutualisms contribute to island species deficit at the global scale</b>

However, the role of ant-plant mutualism in shaping this species deficit remains poorly understood. Here we used the Global Inventory of Floras and Traits (GIFT) database and the Global Ant Biodiversity Informatics-Island (GABI-I) database to explore the potential mechanisms underlying the effects of ant-plant mutualism on biodiversity of oceanic islands.

Our results showed that the strength of ant–plant mutualism on the mainland had a significant positive effect on the oceanic island–mainland plant diversity difference at a given latitude (i.e., the oceanic island species deficit). Although non-myrmecophytic plants contribute more to the absolute species deficit (due to their larger mainland species pool), the mean proportional species deficit is significantly higher for myrmecophytic plants than for non-myrmecophytic plants.