Visitation by Wild and Managed Bees (Hymenoptera: Apoidea) to Eastern U.S. Native Plants for Use in Conservation Programs

Abstract

Addition of floral resources to agricultural field margins has been shown to increase abundance of beneficial insects in crop fields, but most plants recommended for this use are non-native annuals. Native perennial plants with different bloom periods can provide floral resources for bees throughout the growing season for use in pollinator conservation projects. To identify the most suitable plants for this use, we examined the relative attractiveness to wild and managed bees of 43 eastern U.S. native perennial plants, grown in a common garden setting. Floral characteristics were evaluated for their ability to predict bee abundance and taxa richness. Of the wild bees collected, the most common species (62%) was Bombus impatiens Cresson. Five other wild bee species were present between 3 and 6% of the total: Lasioglossum admirandum (Sandhouse), Hylaeus affinis (Smith), Agapostemon virescens (F.), Halictus ligatus Say, and Ceratina calcarata/dupla Robertson/Say. The remaining wild bee species were present at <2% of the total. Abundance of honey bees (Apis mellifera L.) was nearly identical to that of B. impatiens. All plant species were visited at least once by wild bees; 9 were highly attractive, and 20 were moderately attractive. Honey bees visited 24 of the 43 plant species at least once. Floral area was the only measured factor accounting for variation in abundance and richness of wild bees but did not explain variation in honey bee abundance. Results of this study can be used to guide selection of flowering plants to provide season-long forage for conservation of wild bees.

Land-use change reduces habitat suitability for supporting managed honey bee colonies in the Northern Great Plains

“…To maximize conservation investments, land management activities designed to benefit pollinators should be developed within an adaptive management framework so that management uncertainties can be addressed during the early stages of program development. In addition to quantifying large-scale habitat features that pollinators require, finer scale studies are also needed to investigate floral resources that maximize benefit to pollinators and will grow readily in agricultural landscapes (43)(44)(45). This information can be useful for designing and evaluating conservation seed mixes that are cost-effective for implementing across large spatial extents and regional programs.…”

Spillover of functionally important organisms between managed and natural habitats

“…For example, a study which monitored both wild pollinators and managed honeybee visits on native plants found that the managed honeybees visit 24 of the 43 species of flowering native plants found on the edges of agricultural land (Tuell et al, 2008), possibly contributing to increases in plant fitness. In some systems, honeybee populations from modified habitats may partially compensate for the declines of native pollinators in natural habitat fragments, but this is not always the case (see Garibaldi et al, 2011).…”

Intersection between biodiversity conservation, agroecology, and ecosystem services

“…Movement of herbivores, pollinators, and natural enemies to natural habitats can have positive and negative effects on function in natural habitats. Some studies suggest that some native plant species, for example, may benefit from the spillover of bees from agroecosystems into natural fragments (Hagen and Kraemer 2010;Tuell et al 2008), while others show that cultivated crops can compete for pollinators, especially during times of mass flowering of crops, thus reducing wild plant fitness in forest fragments (Aizen, Morales, and Morales 2008;Lander et al 2011). Kovacs-Hostyanszki et al (2013) study suggests that the strength and direction of the effect of mass-flowering crops on wild plant pollination services depend on the spatial and temporal scale considered and on the habitat type, the wild plant species, and the time of crop flowering.…”