Global meta‐network of legume crops and floral visitors reveals abundance of exotic bees

Abstract

AbstractLegume crops (family Fabaceae, order Fabales) constitute a relevant component of the human food supply. In view of the global decline in crop production, as a result of increasing threats (such as habitat fragmentation and land use change) to pollinators, knowledge concerning legume floral visitors can contribute to world food security. In this study, a synthesis was performed of global data on interactions between legume crops and their floral visitors, in order to improve understanding of the structure of crop‐floral visitor interactions and the roles of different species. A literature review was conducted using three databases, considering 15 legumes of economic importance, enabling the construction of a meta‐network of plant‐floral visitor interactions. Soybean, alfalfa and common bean received the highest numbers of floral visitor species. A total of 208 floral visitor species were recorded, distributed in eight orders. The most diverse group was Hymenoptera (mainly bees), followed by Lepidoptera. The European honeybee Apis mellifera interacted with the highest number of plant species. Modularity analysis identified eight modules that included more than one order of floral visitors. Most species were classified as peripherals, with few links restricted to their own module. The three connector species were the bees Bombus pascuorum, B. terrestris and Megachile rotundata. The only network hub was A. mellifera. The predominance of bees seemed to be related to the predominant floral morphology among the crops. The connector and hub species were typically generalists, and all except one species (B. pascuorum) were used as managed pollinators. The crops studied have an important role in global pollination resilience, maintaining a diversified fauna of pollinators other than bees.