Pan Compared to Malaise Trapping for Bees (Hymenoptera: Apoidea) in a Longleaf Pine Savanna

Insects are diverse in their habits and a wide variety of trapping methods have been developed to capture them. Bees are no exception. Although malaise traps have traditionally been the method of choice for Hymenoptera, (Matthew and Matthews, 1971; Masner and Goulet, 1981; Noyes, 1989), netting is used more often for bees because it provides better quality specimens and generates floral visitation data. A disadvantage of netting is that it requires more effort than passive collecting methods and can generate limited samples. To overcome this, a second passive collecting method, pan trapping (Leong and Thorp, 1999), is often combined with netting. In an attempt to standardize collecting methods for bees, a Bee Inventory (Bl) Plot protocol (http://online.sfsu.edu/~beeplot) was developed that combines netting and pan trapping with specified temporal and spatial parameters for each. As a side project of a larger study surveying bee diversity in Louisiana longleaf pine savannas (Bartholomew, 2004), we compared the efficiency of a malaise trap protocol with the Bl Plot protocol. Because we were surveying for a number of different insect orders (ants, beetles, and grasshoppers), we used malaise and flight intercept traps, which catch a wide range of groups. When we discovered the Bl Plot protocol existed, we wanted to know the extent to which our study was compromised, if any, by not using this method. Here, we report results from both trapping protocols over a four month period in one of our savanna sites.