It has been estimated that native bee species account for nearly $3.07 billion of fruits and vegetables in the United States, making bees an important component of our economy (Losey, 2006). The global decline of both natural and managed bee populations have created an increased demand for further research, warranting the need for reliable methods of measuring bee biodiversity (Tirado, 2013). Pan traps, sweep netting, and blue vane traps are standardized methods used for sampling native bee communities. We compared the effectiveness and uniqueness of these sampling methods using simultaneous sampling at biweekly intervals from 9/2/2014-11/15/2015 at the Center for Biological Field Studies in Walker County, Texas. Three colors of pan traps were used, white, blue, and yellow, organized in a repeating color sequence. Six transects of 75 meters received 15 pans, five of each color and two blue vane traps, hung at 1.5m in height. Pan and blue vane traps were filled with soapy water and collected the next day. When the pans were collected the transects were sampled by netting the entire area surrounding each transect for 30 minutes, capturing bees as encountered on all blooming plants. Bees were identified using literature keys and Discover Life.
Results/Conclusions
Over 35 different sample days, a total of 31 pan trap, 25 blue vane, and 25 sweep net samples were taken. 1695 specimens (1368 females, 327 males) from 103 species of bees from five families (Andrenidae, Colletidae, Halictidae, Megachildae, Apidae) were collected, including 1 non-native bee (Apis mellifera). Pan traps collected 62% of specimens and species, blue vane traps collected 11% of specimens and 31% of species, and sweep netting collected 27% of specimens and 65% of species. Species unique to a single trap type were 10% (blue vane), 28% (sweep net), and 51% (pan trap). Pan traps collected large numbers of Lasioglossum (Dialictus) specimens and species, while blue vane traps preferentially collected fast-flying large bodied bees such as Melissodes bimaculata. Sweep netting captured a wide variety of body sizes. This study demonstrates that these three sampling methods are complementary and can produce a relatively comprehensive community sample in <2 years. Eleven species are new records for Texas, representing a western extension of a bee fauna primarily allied with pine forests of the Southeastern United States. Three Lasioglossum (Dialictus) species are undescribed species.