Summary1. Bee pollinators provide a critical ecosystem service to wild and agricultural plants but are reported to be declining world-wide due to anthropogenic change. Long-term data on bee abundance and diversity are scarce, and the need for additional quantitative sampling using repeatable methods has been emphasized. Recently, monitoring programmes have begun using a standardized method that employs a combination of pan traps and sweep netting, resulting in lethal sampling of bees. This standardized method can remove a large number of bees from sites during each sampling day, raising concern that the sampling itself could have a negative effect on bee populations. 2. We conducted an experiment to assess whether lethal sampling for bees using pan traps and netting affected bee abundance and diversity when done every two weeks throughout a season and over multiple years. We compared bee abundance, richness, evenness and functional group composition between sites that had been sampled every two weeks from 2009 to 2012 to similar sites not previously sampled. 3. We found that the standardized method for sampling bees, with specimens from 132 morphospecies, did not affect bee communities in terms of abundance, rarefied richness, evenness, or functional group composition. Thus, our results indicate that the bee communities we sampled are robust to such sampling efforts, despite removing an average of 2862 bees per season. 4. We discuss several explanations for why sampling did not affect bee abundance or community structure, including a density-dependent response to reduced competition for resources. 5. These results suggest that bee monitoring programmes sampling once every two weeks with pan traps and netting will not affect bee community structure. We urge researchers monitoring bees to utilize standardized protocols so that results can be compared across space and time.

This contribution results from an investigation of four commercially obtained colonies of Bombus (Pyrobombus) impatiens Cresson in an attempt to understand the functional anatomy and behavior of its immature stages. Eggs are described in detail, and their chorionic microstructure is contrasted with that of Bombus (Cullumanobombus) griseocollis (De Geer). They are deposited in groups consisting of a few to more than nine eggs into a single chamber. The study confirms that larvae pass through four instars. Although increasing in size dramatically from one instar to the next, larval anatomy and behavior change little during the first three instars. The last instar is the one that commences defecation and production of silk resulting in cocoon construction. In contrast to most bees, its larval activities result in substantial changes in size and shape of its brood chamber, whereas brood chambers of most bees are constructed by the female and modified little by the offspring. This study is a part of a series of investigations into the similarities and differences in the developmental biologies among corbiculate bees.

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This, the second study of the nesting biology of Lithurgus chrysurus Fonscolombe found at Palmerton, Carbon Co., Pennsylvania, describes its nest construction, provisioning, egg deposition, and larval development. The first study (rozen, 2013) was based on observations on the late-stage nesting biology in early fall, when these activities were no longer being performed. Comparisons are made with activities of the native Lithurgopsis apicalis (Cresson); in general, the two species have similar, but not identical, nesting biologies. Because Lithurgus chrysurus is an adventive bee native to the Mediterranean regions and is capable of constructing nests in both soft wood as well as firmer wood, it is unclear why it has not expanded its range to any great extent in the new World.

This contribution results from an investigation of four commercially obtained colonies of Bombus (Pyrobombus) impatiens Cresson in an attempt to understand the functional anatomy and behavior of its immature stages. Eggs are described in detail, and their chorionic microstructure is contrasted with that of Bombus (Cullumanobombus) griseocollis (De Geer). They are deposited in groups consisting of a few to more than nine eggs into a single chamber. The study confirms that larvae pass through four instars. Although increasing in size dramatically from one instar to the next, larval anatomy and behavior change little during the first three instars. The last instar is the one that commences defecation and production of silk resulting in cocoon construction. In contrast to most bees, its larval activities result in substantial changes in size and shape of its brood chamber, whereas brood chambers of most bees are constructed by the female and modified little by the offspring. This study is a part of a series of investigations into the similarities and differences in the developmental biologies among corbiculate bees.