Is pan trapping an effective method for estimating hymenopteran diversity in grasslands?
Monday, November 16, 2015
Exhibit Hall BC (Convention Center)
Morgan P. Rondinelli
,
National Museum of Natural History, Smithsonian Institution, Washington, DC
Sam Droege
,
Patuxent Wildlife Research Center, U.S. Geological Survey, Beltsville, MD
Abigail A.R. Kula
,
Department of Science, Mount St. Mary's University, Emmitsburg, MD
David R. Smith
,
Beltsville Agricultural Research Center, Northeast Area, USDA - ARS, Washington, DC
Robert Kula
,
Beltsville Agricultural Research Center, Northeast Area, USDA - ARS, Washington, DC
Grasslands are among the most endangered ecosystems in North America due to conversion of historical grassland to crop fields or habitat loss through urbanization. It is essential to document biodiversity in grasslands for successful conservation and restoration. Pan trapping is used frequently to estimate hymenopteran diversity in grasslands. However, dense vegetative growth hinders the use of pan traps in some types of grasslands. This project compared the efficacy of ground-placed pans, pans elevated 1.2 meters off the ground, and sweep netting for estimating Symphyta (sawflies, woodwasps), Braconidae (parasitoid wasps), and Anthophila (bees) diversity in grasslands. The goal was to discern which method, or combination of methods, best estimates diversity for insects that provide critical ecosystem services like herbivory, parasitism, and pollination.
Specimens were collected at three grassland sites in Virginia. Two sites were sampled every two weeks April-October in 2014, and one site was sampled every two weeks June-October in 2015. The sites in 2014 were sampled using three pairs of transects in each site, with each transect containing 15 elevated or ground-placed yellow pans. The site in 2015 involved five meadows sampled using one pair of transects in each meadow, with each transect containing 18 elevated or ground-placed yellow pans. The 2015 site was also sampled with a sweep net using 140 sweeps per meadow.
Sampling in 2014 resulted in 121 and 266 specimens of Symphyta and Braconidae, respectively. The average number of Symphyta specimens collected per transect for the whole collection period was 17 and 4 for elevated and ground pans, respectively. The average number of braconid specimens collected per transect for the whole collection period was 11 and 33 for elevated and ground pans, respectively. Processing of bee specimens from 2014 (~4000) is ongoing, as is specimen collection and preparation of all three groups for the 2015 site.
