Shifting Phenologies of Agriculturally Important Native Bees over Five-Years: Effect of Fluctuating Spring Conditions on Emergence, Abundance and Overall Community Richness

Commercial fruit and vegetable agriculture is dependent on bees for pollination services.  In a five-year study (2010-2014), the emergence and abundance patterns of major native bee groups, who play critical roles as pollinators in commercial agriculture, was investigated. Our study took place in Georgia apple orchards over the entire growing season with special emphasis on the apple bloom.  The 2010 season followed a typical early April apple bloom dominated by mining bees (Andrena species), which serve as the main early season pollinator in Georgia.  In 2011 and 2012, the apple bloom occurred 2 to 4 weeks early.  During these blooms, much fewer mining bees were present; however, greater abundances of mason bees (Osmia species) and other bees were documented. In 2013, the apple bloom was 2-3 weeks later than the traditional bloom, and was marked with much great bee diversity and abundance than in the previous two years.  The 2014 season, once again followed a typical early April apple bloom, which was dominated by mining bees. In order to use native pollinators successfully in commercial agriculture, we will need to gain a better understanding of these dynamic systems.