Abstract:

Aims: Bees and wasps constitute an important functional group in agroecosystems, encompassing pollinators that provide pollination services, as well as parasitoid wasps and predatory wasp assemblages involved in pest regulation. Elucidating the spatiotemporal variation patterns and driving mechanisms of their community structures is of great significance for the conservation of pollinator diversity and farmland natural enemy diversity. However, the relative contributions of habitat types and monthly dynamics to bee and wasp communities remain poorly understood in tropical agricultural landscapes. 

Methods: A one-year monthly survey of bee and wasp taxa was conducted across four habitat types (roadside, wasteland, farmland, and woodland) in the agricultural landscape of Danzhou Campus, Hainan University. We applied α-diversity indices, non-metric multidimensional scaling (NMDS), permutational multivariate analysis of variance (PERMANOVA), β-diversity partitioning, and indicator species analysis to systematically explore the spatiotemporal variation and driving mechanisms of bee and wasp community structure. 

Results: A total of 2,943 bee and wasp individuals were collected, belonging to 120 species, 75 genera, and 17 families. After controlling for sampling intensity measured (as the number of effective monthly sweep net sampling times), the main effect of habitat type was not statistically significant for any α-diversity index, although the median values differed among habitat. PERMANOVA revealed that both habitat and month were significantly associated community composition, with month explaining a higher proportion of community variation than habitat. β-diversity partitioning indicated that community dissimilarity at both habitat and temporal scales was predominantly driven by species turnover, while the contribution of nestedness was low. Indicator species analysis revealed that the roadside habitat harbored 18 significant indicator species (including Apis cerana, Apis mellifera, and Amegilla sp. 1), woodland habitat had one significant indicator species (Cremnops sp. 1), while farmland and wasteland had no significant indicator species. 

Conclusions: In tropical agricultural landscapes, temporal turnover across months is the primary driver of compositional variation in bee and wasp communities, accounting for 19.9% of the total variance, while habitat type contributes far less explanatory power at only 9.5%. Species turnover constitutes the core process underlying both spatial and temporal differentiation of bee and wasp communities. Our findings highlight the crucial role of temporal processes in bee and wasp community assembly, and provide a theoretical basis for bee and wasp biodiversity conservation and habitat management in tropical agroecosystems.

Key words: bees and wasps, habitat heterogeneity, monthly dynamics, community structure, α-diversity, β-diversity, species turnover