Studies of Bee Diversity in Indiana: The Influence of Collection Methods on Species Captures, and a State Checklist Based on Museum Collection

Abstract

Bees are among the most important of pollinators, but little is known about their status. I expand the knowledge of the bees of the Midwest by updating the bees of Indiana, the first update in over fifty years, by adding two local bee species inventories, in the black oak savannas of northeastern Indiana and another reconstructed based on museum specimens, and by comparing two methods for sampling bees. Bees from six families, 52 genera, and 416 species are represented in Indiana, an addition of over 200 species from precious lists. Species ranged from common to rare with a median abundance of 22 specimens. Distributions, life histories, flight decade, but several species have not been collected in the last 20-50 years. These are mainly rare or were last collected in an area or on a host flower species which has not been sampled recently. Four bumble bee species appear to be declining and another is likely extirpated. Bees are commonly sampled either by netting at flowers or by bowl trapping. The bases of these techniques were explored while inventorying black oak savannas. Netting at flowers collected more species at any given site, but using both methods gave the best picture of species richness. Both techniques collected all common species and differed mainly in the rare species collected. Smaller bees were significantly more likely to be captured in bowls, especially within the families Halictidae and Apidae. Bowls were also more likely to catch more bees when fewer flower resources were available for bees. These studies represent a significant addition to knowledge of bee distribution and abundance in the Midwest.