Submitted to: Pan Pacific Entomology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2005
Publication Date: 2/1/2005
Citation: Toler, T.R., Evans, E.W., Tepedino, V.J. 2005. Pan-trapping for bees (Hymenoptera: Apiformes) in Utah's west desert: the importance of color diversity. Pan Pacific Entomology. 81(3/4):103-113. Interpretive Summary: Pan Traps (plastic cereal bowls filled with water and a drop of detergent as a surfactant) are brightly colored bowls used to passively sample bee species in natural and agricultural communities. They have been advocated by some as an unbiased method to monitor native bee populations. We used pan traps in three colors attractive to bees (blue, yellow, white) to survey the military lands in Utah's west desert. We found a total of 84 bee species in our five weeks of sampling. All abundant bee species displayed preferences for bowls of particular colors. Each color was preferred by at least one species of bee. To enumerate the bee diversity of a given area, a range of pan trap colors must be employed.
Technical Abstract: We used pan traps in three colors (blue, yellow, white) to sample the bee fauna on five sand dune sites on military lands in the west desert of Utah. Our primary objectives were to 1) compare bee species richness and similarity among the three colors; 2) estimate the incidence of color preference among bee species; 3) examine the effect of background bloom color on pan trap color preference. We found the colors to be equivalent in the numbers of bee species captured: each color captured about two-thirds of the 84 total species recorded with an average similarity between colors of about 0.70 (Sorenson Index). Average similarity among colors was much higher (0.93) when only abundant species were considered. All bee species represented by sufficient numbers displayed significant color preferences. Each color was preferred by at least one species. We found no indication that the prevalent color of flowers in bloom during each site-week had an effect on occurrence in pan traps. Those seeking to exhaustively enumerate the bee fauna of an area using pan traps should employ a diversity of colors to ensure capturing uncommon species with color preferences.