Beyond flowers: including non-floral resources in bee conservation schemes
Journal of Insect Conservation
Land-use change and habitat loss have profoundly disturbed the resource availability for many organisms in farmlands, including bees. To counteract the resulting decline of bees and to maintain their pollination service to crops, bee pollinator-friendly schemes have been developed. We assessed the most established bee pollinator-friendly schemes which mainly aim at enhancing the availability of floral food resources and, or, nesting sites. We found that the availability of non-floral resources was typically overlooked in these schemes, although more than 30% of bee species worldwide depend on non-floral resources. In this opinion paper, we call for more attention on the role of non-floral resources in such conservation schemes. In fact, at least two of the most species rich Apoidea families, the Apidae and Megachilidae, need non-floral resources for nest building, defence, protection and health. For example, resin is known to improve health and resistance to pests and pathogens in stingless bees and the western honey bee Apis mellifera. Beyond social bees, many solitary bee species, in particularly within the Euglossini, Centridini and Megachilidae, also use resin, leaf pieces, trichome secretions and other materials for the construction and protection of brood cells and the nest. Besides protection, non-floral resources can also provide alternative food resources for bees, e.g. sugary secretions from other insects. Surprisingly little is known on this insect-insect interaction although some studies suggest that honey production by beekeepers can largely depend on this alternative food resource. The apparent knowledge gap on the role of non-floral resources for bees can thus directly concern stakeholders. Interestingly, many non-floral resources are provided by woody vegetation, but most of the bee pollinator-friendly schemes are currently orientated towards enhancing flower availability in field margins and flower strips. We therefore suggest more attention in the protection of trees and hedgerows in conservation, restoration and management schemes to best supporting bee health by providing combined access to nesting, floral and non-floral foraging resources.
Author(s): Requier, F; Leonhardt, SD
Journal: Journal of Insect Conservation