NESTING BEHAVIOR OF MEGACHILE PROSOPIDIS IN URBAN AND NATURALIZED AREAS

Abstract

As urbanization becomes increasingly widespread, understanding the role of cities in supporting ecosystem services is crucial. The nesting behavior of a native leafcutter bee, Megachile prosopidis, was studied in order to examine differences in nesting behavior in urban versus naturalized environments. This study was particularly focused on the heterogeneity of nest tube end plugs. Over 180 filled nest tubes were collected from wooden nest blocks installed in and around Tucson and categorized into two primary structure classes. Structure class one consists of smooth dirt, plant resin, and pure resin end plugs. Structure class two consists of plant debris and lumpy debris end plugs. All five end plug categories were present at urban sites. Plant debris end plugs were absent from naturalized sites. High variability was present both within and across categories, suggesting flexibility in end plug construction materials. Both habitat type and site nested within habitat had a significant effect on end plug frequencies. The variability in nest tube end plug construction of M. prosopidis suggests flexibility in the proportion of resin usage and nesting materials based on site and habitat resources. A significant male-biased sex ratio was found. The function and implications of nest plug variability warrant further research, particularly on effectiveness of protection against parasitism.