The coexistence of two related fig wasp species sharing the same host fig species across a broad geographical area

Abstract

Although more and more cases of breakdown of the 1: 1 partner specificity are being documented, figs and their pollinating fig wasps constitute perhaps the most tightly integrated pollination mutualism known. However, there are rare occasions where the pollinating fig wasp evolves cheating in this obligated system. The pollinator loses the ability to carry pollens but still lays eggs in female flowers. It has been reported that the figs of Ficus altissima, a functionally monoecious fig species, are occupied by two Eupristina species, the effective pollinator Eupristina altissima and the cheater Eupristina sp. in Xishuangbanna, SW China. However, little is known about whether the two Eupristina species entering figs can coexist widely in the nursery pollination system. Here, we used molecular methods to investigate the genetic diversity of Eupristina species in the widespread Asian fig species. Standard barcoding genes support two wasp species. Both fig wasp species were co-occurring in most distribution regions, raising the question of how two species can coexist within similar or identical resource niches. Our study offers a striking example of two closely related fig wasps that share a host can co-exist across a broad geographic area in a natural setting, but the pollinating wasps are more abundant.