The associations between floral traits and pollinator groups in two Mediterranean mountainous plant communities in the Middle Atlas of Morocco

The relationships between floral traits and pollinators have been extensively studied over the last few decades. The concept of pollination syndrome suggests that plants pollinated by the same group of pollinators tend to develop similar combinations of floral traits. However, several studies have demonstrated the low predictability of these trait combinations and found high levels of pollination generalization within plant communities. In this context, on the basis of direct field observations, our study aimed to explore the relationships between pollinator functional groups and floral traits in two Mediterranean mountainous plant communities in the Middle Atlas of Morocco. Our research included 83 plant species belonging to two plant communities and 10 insect groups. Pollination generalization (PG) levels varied significantly between the two plant communities. Among the thirteen floral traits included in the present study, PG levels were significantly associated with only flower clustering and reward type. Clustered flowers and those producing both nectar and pollen were more generalized than solitary flowers and those producing only pollen. Bumblebees frequently visit closed zygomorphic flowers with hidden anthers in a vertical orientation, whereas flies, hoverflies, and ants prefer open actinomorphic flowers with exposed anthers in a horizontal orientation. Butterflies and beeflies were strongly associated with tubular flowers with long corollas and pink colouration. In addition to being the most abundant group, bees and beetles exhibited generalist behavior, with associations with multiple floral traits in both communities. Our results, while offering partial support for the pollination syndrome hypothesis, revealed predominantly generalized patterns of pollination among the studied plant species. Notably, these patterns were not significantly explained by all the floral traits we analysed. Furthermore, we suggest that within insect groups, especially bees and beetles, species-level variation in floral trait preferences may exist, contributing to the observed generalizability. These findings highlight the need for further research to unravel the intricacies of plant–pollinator interactions and to better understand the mechanisms driving network structure and specialization.