Format: ORAL

Yedra Garca1, Michael Hedrn1, Magne Friberg1,ystein H. Opedal1

Biology Department, Lund University, Lund, Sweden

Interactions for pollinators among co-flowering species are common and can modify plant reproductive success and ultimately natural selection on floral traits. However, studies considering the effects of the whole co-flowering community are still rare. Food-deceptive orchids provide suitable models to test for community effects on plant fitness as they often depend on rewarding co-flowering species to attract pollinators. Novel statistical approaches such as hierarchical latent-variable joint models now allow testing the influence of multiple co-flowering species on plant reproductive success. Here, we used two food-deceptive orchids Dactylorhiza majalis subsp. lapponica and D. majalis subsp. majalis to address the effects of the co-flowering community on pollination and plant reproductive fitness. We implemented the Hierarchical Modelling of Species Communities (HMSC) framework by fitting hierarchical latent-variable joint models with relative pollination success and fruit set as response variables. Together with phenotypic traits, we included the animal-pollinated co-flowering species in the community of each orchid as model predictor by using a reduced-rank regression approach in HMSC. Our results revealed that the animal-pollinated co-flowering community affected both pollination success and reproductive fitness via fruit set. Moreover, for D. lapponica, we found that the effect of animal-pollinated co-flowering species was strong even after accounting for effects of non-animal pollinated species in the community. By using a reducing-rank regression approach within the HMSC framework, we yielded new insights on the biotic factors influencing pollination and reproductive success of deceptive pollinated species. This approach can be extended to other pollination systems and plant communities and highlights the importance of considering the whole co-flowering community to understand the ecology and evolution of flowering plants in multispecies communities.