A Six-Year Study of Hoverfly (Family Syrphidae) Diversity and Abundance in Georgia Apple Orchards

Flower flies (Family Syrphidae), also known as hoverflies, are pollinating insects that mimic bees in external anatomy (black and yellow color patterns). A survey of Family Syrphidae was performed from 2010-2015 in five large apple orchards in North Georgia (8-10 collections per site per year).  Collection methods included: pan traps, malaise traps, and one-hour timed sweep netting. There were approximately 150-300 flower flies collected each year.  The most abundant species were: Toxomerus geminatus and Toxomerus marginatus. The species collected indicate a diverse assembly of flower flies in Georgia. Flower flies significantly (p= .0001) preferred yellow trap color to other colors (blue and white). Pan traps collected the largest raw number of flower flies and the most different species.  During the study, flower flies were observed in orchards 2 to 4 weeks prior to the emergence of native bees and other pollinators.  This survey is one of the first steps in discovering and documenting the diversity and abundance of flower flies in the southeastern United States.  Based on other regional studies in the past, it is likely Georgia has 40-80 species.  Additional surveys are needed to fill in the complete picture of the biodiversity of these important pollinators and pest-mangers.