From metropolis to wilderness: Uncovering pollen collecting behavior in urban and wild sweat bees (Halictus ligatus)

• Published in: Urban ecosystems 2024-04, Vol.27 (2), p.563-575
• Main Authors: Brant, Rachel A., Dunlap, Aimee S.
• Format: Article
• Language: English
• Subjects: Animal behavior; Animal populations; Bees; Biomedical and Life Sciences; Breeding success; Documents; Ecology; Ecosystem services; Environmental factors; Environmental Management; Foraging behavior; Halictus ligatus; Heterogeneity; Life Sciences; Nature Conservation; Plants (botany); Plastic properties; Plasticity; Pollen; Pollination; Reproduction; Species richness; Sweat; Urban areas; Urban Ecology; Urban populations; Urbanization; Wilderness
• ISSN: 1083-8155; 1573-1642
• DOI: 10.1007/s11252-023-01466-1

Urban areas boast high bee species richness and abundance, but little is known of their overall behavior or potential plasticity. The physical movements of bees on flowers are an extremely important aspect of their behavioral repertoire, as foraging for pollen has implications for bee population health and plant reproductive success. In this study we used classic ethological techniques to document and quantify pollen collecting behavior common sweat bee species, Halictus ligatus, residing in both urban and exurban habitats, and assess the role of environmental factors on behavioral differences. Overall, time budgets of bee foraging behavior between urban and exurban H. ligatus were similar, with scraping as the primary method used for pollen extraction . However, we observed a novel foraging behavior for Halictus bees – tapping, which varied significantly between urban and exurban bee foragers. Additionally, environmental characteristics including temperature, floral richness and floral identity were the strongest predictors of pollen collecting behavior. Lastly, we found significant differences in the sequences of behaviors performed by urban and exurban H. ligatus . This study is the first to utilize ethological methods to describe and document pollen gathering in an urban sweat bee species, and explore the potential mechanisms driving behavioral differences. The physical actions involved in pollen removal are crucial for plant pollination, particularly in urban regions with high habitat heterogeneity and resource patchiness. As urbanization continues to expand, more targeted behavioral studies applied to urban animal populations will aid in our understanding of animal behavior, plasticity, and the potential implications for ecosystem services.