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Texas Tech University (TTU) 2018

Co-occurrences and behavioral interactions of wild bees and managed honey bees on flowering plants in a semi-arid agroecosystem

Rendon, Bianca Marie

Titre : Co-occurrences and behavioral interactions of wild bees and managed honey bees on flowering plants in a semi-arid agroecosystem

Auteur : Rendon, Bianca Marie

Université de soutenance : Texas Tech University (TTU)

Grade : Master of Science (MS) 2018

Résumé
Pollinators are highly valuable as both supporters of wild flowering plant communities and as providers of human ecosystem services. In recent years population declines in both managed and unmanaged bees have occurred due to multiple threats associated with land-use change and concordant intensification of human activities detrimental to pollinators. Managed honey bee pollinators have been widely used in many crops because they are very effective at foraging and moving pollen, thus providing agronomic value through improvements in crop yield. Across landscapes, both managed bees and wild bees share floral resources, and therefore interactions can occur that facilitate or potentially inhibit foraging patterns and densities, with potential implications for crop production and also the maintenance of wild flowering plant communities. The objective of this study was to determine abundances, foraging, and behavioral interactions of managed honey bees and native bees in a semi-arid grassland agroecosystem in relation to honey bee hive manipulations. In three defined periods (i.e. before, during, and after honey bee hive removal from the local study site) across four honey bee hive manipulation events, the abundances of honey bees, bumble bees, halictid bees, non-halictid bees, and other non-bee pollinators, individual foraging behaviors, and behavioral sequences were recorded and compared across the three different periods using Kruskal-Wallis non-parametric ANOVA, behavioral transition matrices, and regression analysis. Honey bee, non-halictid, Halictidae, and other pollinator abundances were shown to change as a result of hive removal, but changes in abundances during hive manipulation periods were only significant for honey bees, non-halictids, and other non-bee pollinators. Halictidae abundances trended upwards during the period of honey bee hive removal, with halictid numbers showing a decline once honey bee hives were returned. Non-halictid bees performed behaviors more frequently and foraged for five additional seconds (P = 0.033) when hives were returned to the local field (i.e. the “after” period). Even though several one-way behavioral transitions that were shown to be significant during hive manipulations, the hive manipulations did not significantly influence bee foraging sequences. Common significant behavioral transitions include approach - pollen gathering, pollen gathering - move-to, and move-to - approach for each bee group and hive setting. Near significant interactions (Kruskal-Wallis, χ2 = 5.677, df = 2, P = 0.059) between Halictidae and other bees occurred as a result of hive removal. While some changes were observed in native bee abundances and foraging in relation to local hive manipulations, the results of our study did not fully support the hypothesis that native bee communities proximal to abundant managed honey bee colonies undergo broad behavioral or numerical changes because of introductions or removal of local honey bee hives.

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Page publiée le 14 novembre 2018