Discipline: Biological Sciences
Luisángely Soto-Torres - University of Puerto Rico-Rio Piedras
Co-Author(s): Johanne Brunet, USDA-ARS, Madison, WI
Features of the agricultural landscape can influence the foraging behavior of pollinators which can mediate gene flow. Residence represents the number of flowers a pollinator visits during a foraging bout or between the time it enters and leaves a patch. When a bee moves from a transgenic to a conventional patch of alfalfa, the more flowers are visited in the conventional patch the more likely the transgenic pollen on the bee’s body will get depleted in that patch which would reduce gene flow. Residence may therefore be inversely proportional to gene flow risk. Understanding the dynamics of pollinator-mediated gene flow is important to facilitate the coexistence of different agricultural seed markets. The objective of this study was to determine how patch size and isolation distance, when combined in an experimental design, would influence residence of bumblebees foraging on Medicago sativa. Four patches of alfalfa, two large (225 plants) and two small (100 plants), were set up at two distances (9.1m/18.2m) from a center patch (100 plants). Two bumblebee hives were brought to the fields and placed around the edge of the center patch. The Brunet laboratory previously tested the impact of patch size and isolation distance in separate experiments using three bee species and observed higher residence in larger patches or in farther patches. We therefore predicted higher residence in larger patches and in patches farther from the center patch. An interaction between patch size and isolation distance could be tested in this experiment and might occur if the impact of patch size on residence differed between near and far patches. The impacts of patch size and isolation distance and its interaction on residence were tested using a two-way analysis of variance on log transformed residence data. Bumblebees had higher residence in large relative to small patches. However, bees visited as many flowers in far as in near patches and no significant interaction was detected between patch size and isolation distance. Only patch size affected residence in this study and bumblebees visited more flowers (38.3 flowers ± 8.5) in large relative to small (17.1 ± 5.3) patches. These results suggest that planting larger patches of conventional alfalfa in the vicinity of genetically modified alfalfa would reduce gene flow risk in alfalfa seed production fields. To generalize results, we will measure residence in an additional field replicate with a different patch size configuration. References: Brunet, J. & Clayton, M. (2017). The impact of patch size and isolation distance on bee foraging behavior: Implications for pollen dispersal and gene flow risk. Poster. NIFA-BRAG PI meeting, Washington D.C. Cresswell, J. E. & Osborne, J. T. (2004). The effect of patch size and separation on bumblebee foraging in oilseed rape: implications for gene flow. Journal of Applied Ecology 41: 529-546.JB-LST-2018_ERN_Conference_Abstract.docx
Funder Acknowledgement(s): This project was supported by the Biotechnology Risk Assessment Grant Program competitive grant no 2013-33522-2099 from the USDA National Institute of Food and Agriculture, WISCIENCE, National Science Foundation (NSF) Biological SIGNALS REU Award #1659159. Many thanks to Gregory Gelembiuk for his mentoring, Austin Staudinger and Talaidh Isaacs for their assistance in residence data collection, and Emmanuel Santa-Mart?nez and Danny Minahan for their guidance during the execution of this study.
Faculty Advisor: Johanne Brunet, firstname.lastname@example.org
Role: I collected bee residence data in the field. Additionally, I organized data with the help of other undergraduate students. Lastly, I worked with data compilation and assisted in the analysis.