Measuring trap success surveying native pollinators in an agricultural environment: A comparison of vane traps and pan traps with color and elevation differences

In surveying native pollinators, 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 potentially play a role in the success of the sampling method. In the following study, four Georgia apple orchards were setup using the same 100mX100m plot design, which were then sampled routinely from March-October, 2010. Trap variations were identical for each site, and included color (UV-reactive yellow, UV-reactive blue, and white) as well as trap elevation (level and 3-foot elevated). When comparing trap colors for both vane- and pan-traps, yellow traps attracted the most pollinators overall. Specifically, the Andrenids and Sphecids almost exclusively preferred yellow, while Apids were drawn primarily to blue. Halictid numbers were divided relatively evenly between both yellow and blue. Dipteran pollinators were overwhelmingly drawn to yellow, though many calyptrate flies also frequented blue and white. Differences in trap height resulted in a far less species-specific variation in the number of specimens collected per trap than did color, but did ultimately produce marked differences in the total number of pollinators sampled. Level pan-traps consistently offered more specimens than elevated, though the color of the individual pan was a better guide to estimate potential pollinator sample loads. By and large, 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.