Abstract
To investigate how insect hair morphology influences pollination effectiveness, this study examined four common wild pollinators in Camellia oleifera plantations: two bee species (Colletes gigas and Apis cerana) and two hornet species (Vespa velutina and Vespa soror). We systematically measured hair length, hair density, and pollen loads on four body regions (head, thorax, abdomen, and legs). The results indicated that the following: (1) C. gigas possessed significantly longer and denser hairs across all body parts, especially on the legs, compared to the other three species. (2) Both the pollen load per body part and the total pollen load were markedly higher in C. gigas than in the other pollinators. The two hornet species did not differ significantly from A. cerana in pollen load, and even exceeded it in certain traits such as head hair length. (3) Correlation analysis revealed a significant positive relationship between total pollen load and both hair length (ρ = 0.545, p < 0.01) and hair density (ρ = 0.391, p < 0.01). Pollen loads on different body regions were also strongly positively correlated, suggesting functional synergy across the insect's surface. Leg pollen load correlated positively with head and leg hair length, but negatively with head hair density. Notably, leg hair length and density showed a unique positive correlation, highlighting region-specific morphological adaptation. (4) Cluster analysis separated C. gigas from the other three species, which grouped together. In conclusion, hair length and density-particularly on the legs-are key morphological traits underpinning pollen-carrying efficiency in these pollinators. C. gigas demonstrates superior hair morphology and pollen-carrying performance, supporting its role as an effective pollinator of C. oleifera. This study provides a trait-based framework for identifying dominant pollinators and underscores that evaluating species with complex ecological roles, such as hornets, requires integrating morphological traits with broader behavioral and community contexts.