Impact of urbanization on wild bees underestimated
Wild bees are indispensable pollinators, supporting agricultural productivity and the diversity of plants. Populations of many wild bee species are in widespread decline worldwide to due multiple interacting factors. Habitat loss, urbanization, pesticide use, and climate change have all been blamed.
UNIVERSITY OF MICHIGAN: ‘Wild bees are indispensable pollinators, supporting both agricultural productivity and the diversity of flowering plants worldwide. But wild bees are experiencing widespread declines resulting from multiple interacting factors. A new University of Michigan-led study looked at one topic that has received scant attention from bee researchers: the sex ratio of wild bees and how it changes across a rural-to-urban land-use gradient. The team found that the sex ratio of wild bees became more male-dominated as urbanization increased, mainly driven by a decline in medium- and large-bodied ground-nesting female bees…
Female and male bees of the same species often pollinate different plant species. As a result, a decline in female bees has the potential to limit pollination services for part of the plant community… A declining female population can mean fewer mates for male bees. This threatens ground-nesting bees’ reproduction rates and their ability to maintain future generations of pollinating bees. It may even threaten the genetic diversity of these species…
Results suggest that research may be underestimating the negative impacts of urbanization on ground-nesting bees and highlight the importance of considering sex-specific differences in bee behavior when analyzing the effects of environmental change on bee populations… Populations of many wild bee species are in widespread decline worldwide to due multiple interacting factors. Habitat loss, parasites and disease, pesticide use and climate change have all been blamed. Urbanization contributes to habitat loss, and that trend is expected to accelerate in coming decades’. SOURCE…
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