Which trap type and trap color work best in collecting different groups of bees (Family: Apidae) and pollinating flies (Order: Diptera)?

It is useful to know which traps are most effective in collecting both the highest possible diversity as well as the most individual specimens. Variations in trap type, elevation, and color all play a role in the success of the sampling method. During the past two years, more than 3000 bees and pollinating flies were collected during March-October 2010 and March-October 2011. Sampling was performed every 2-4 weeks in four different North Georgia Apple Orchards. Three trap types were used (pan, vane, and malaise). Pan traps had three different colors (UV-reactive yellow, UV-reactive blue, and white) as well as two different trap elevations (ground level and 3-foot elevated). Vane traps had two colors (blue and yellow). Overall, yellow traps attracted the most pollinators. Specifically, Andrenids, Colletids, and Sphecids almost exclusively preferred yellow traps, while Apids were drawn primarily to blue traps. Halictids were evenly distributed. Dipteran pollinators were overwhelmingly drawn to yellow, though many calyptrate flies also frequented blue and white traps. Trap color had the greatest effect on collection abundance and diversity; however, differences in trap height were significant. Level traps consistently collected more specimens than elevated traps. Malaise traps collected a range of pollinators including rare pollinators not sampled by other traps; however, they collected much fewer bees in comparison to other trap types. In conclusion, yellow vane-traps and level yellow pan-traps were the most effective in collecting the greatest abundance and diversity of native pollinators; however, important exceptions did occur – principally in the family Apidae.