Do larger pollinators have higher pollination efficiency for a generalist plant Hibiscus mutabilis?

Many insect species provide pollination services for flowering plants. However, the pollination efficiency of various pollinator species varies greatly due to differences in body size, foraging behavior, and visitation rate. Here, we investigated a generalist plant Hibiscus mutabilis, and we compared the body size, visitation rate, and pollination efficiency of five pollinator species. Our observations revealed that the pollination efficiency of the moth species was relatively lower than all bee species. The body length of five pollinator species increased the amount of transferred pollen, and larger bees tended to remove more pollen from anthers and deposit more pollen on stigmas, resulting in higher pollination efficiency. However, there was no correlation between the intertegular distance and pollination efficiency of visitors in H. mutabilis. Body length may be a better index of body size than intertegular distance.