Blue and yellow vane traps differ in their sampling effectiveness for wild bees in both open and wooded habitats

Pan trapping is a common method for sampling wild bees, although the use of vane traps is growing globally. Despite this, few studies have tested the effectiveness of different coloured vane traps in attracting bees among different habitat types, and none exist in the southern hemisphere. The present study sampled 192 sites (108 in wooded habitats and 84 in open habitats) within an agricultural region of southern Australia. Pairs of coloured vane traps (one blue and one yellow) were placed at each site for a period of seven days. Combined, 16"‰348 individuals were collected from four families, comprising 13 genera (21 subgenera) and 55 species. Blue vane taps were most effective, sampling six times as many individuals as yellow vane traps and 96% of total species. Their effectiveness was consistent among open and wooded habitat types. The present study highlights the efficacy of vane traps as a passive sampling technique for wild bees. An added benefit of this technique is that vane traps do not require pheromones or lethal agents. A systematic sampling method best suited to the research question should be incorporated into studies of wild bees. For ecological census and population monitoring within multiple habitat types, the present study supports the use of blue vane traps as a major component of the sampling protocol.