Habitat utilization by bumble bees (Bombus spp.) in Denton County, Texas

Bumble bees (Bombus spp.) are adept pollinators of many cultivated and wild flowering plants, but many species have experienced precipitous declines in recent decades.  A variety of factors have been implicated in these declines, including changing land use and associated habitat fragmentation.  The implementation and evaluation of conservation efforts requires information on how populations change over time, but there is a void in data regarding bumble bee populations in many places.  The present research is part of an ongoing study on bumble bees in Denton County, Texas, and serves to establish baseline and current population data for conservation purposes.  Historic museum collection specimens have been catalogued to determine species presence and trends over the past 60 years, and 2013 field surveys of both urban community gardens and minimally-disturbed locations have been performed to ascertain the current status of populations.  Our data document the presence of four species in Denton County (B. pensylvanicus, B. fraternus, B. impatiens, and B. bimaculatus) and suggest that B. fraternus is experiencing local declines.