Testing Pollination Syndromes in Onagraceae, the Evening Primrose family

Background/Question/Methods Pollinators are considered the major selective force in shaping the diversification of angiosperms. The convergent evolution of a defined suite of floral traits to a specific pollinator or pollinator group is known as a “pollination syndrome”. The concept of pollination syndromes has a played a key role in shaping pollination biology research. They have been used to predict the principal pollinator or pollinator group for a plant species. If pollinator syndromes are an accurate hypothesis, we would expect other ecological patterns to emerge, such as a correlation between the conformity to a syndrome and the level of specialization in a pollination system. Using multivariate statistical techniques and detailed pollination data for 54 Oenothera species, we ask the following questions: 1. Do most Oenothera species fit into traditional pollination syndromes? 2. Do these syndromes accurately predict the dominate pollinator for each species? 3. Is there a correlation between degree of specialization and conforming to a syndrome? We used multidimensional scaling techniques to define a “multivariate space” based on traditional pollination syndrome trait descriptions. We then determined if the Oenothera species conformed to these defined pollination syndromes by mapping them into that space. To test the accuracy of the pollination syndrome predictions, we compared the pollinators predicted by the nearest syndrome in the multivariate space to detailed pollination data for these Oenothera.

Results/Conclusions

We find that these Oenothera species do not conform to traditional pollination syndromes. In addition, only 22.2% of the species main pollinator groups were accurately predicted by the nearest pollination syndrome. We do not find a correlation between pollination syndrome and level of specialization of pollination systems. Overall, we conclude that pollination syndromes do not accurately describe the pollination systems for Oenothera.