Cacoxenus indagator is one of cleptoparasites most frequently found in the nests of Osmia bicornis L. The goal of this experiment was to examine the influence of the presence of 2-3 C. indagator larvae in the brood chamber on the cocoon mass, on the mass and size of bee imagines, and on their emergence rate. During the analysis of red mason bee nest material, 200 cocoons were taken from brood chambers, each of them also containing 2-3 larvae of C. indagator (CC). The control group consisted of 200 randomly chosen cocoons from brood chambers with no parasites inside (CFFC). The cocoons and the emerged bees were weighed, and then the size of the bees was determined by the microscope image analysis software Axio Vision Rel. 4.0 coupled with a Stereo Lumar V12 stereoscopic microscope (Carl Zeiss, Germany). This involved measuring the sum of the widths of tergites 3 and 4, the distance between the wings and the forewing length and width. It was found that the presence of 2-3 C. indagator larvae in the brood chamber had no impact on the mortality of bees in cocoons. The research demonstrates that CC cocoons do not have to be removed when collecting cocoons from artificial nests in managed O. bicornis populations, as bees emerging from such cocoons are fully developed.

The diversity and abundance of bumblebees (Bombus Latr.) in eight parks of Warsaw city and the impact of park size (range from 1.9 to 73 ha) as well as other selected characteristics (the percentage of the area covered by tree and the quality of park surroundings) on the bumblebee community were evaluated. In each park, bumblebees were observed along designated paths for 30 minutes. In total, 12 species of bumblebees were recorded, of which four belonged to cuckoo bumblebees (Psithyrus subgenus). We found: B. terrestris (L.), B. lapidarius, (L.), B. pascuorum (Scop.), B. hortorum (L.), B. semenoviellus (Skorikov), B. hypnorum (L.), B. ruderarius (Müller), B. pratorum (L.) and four cuckoo bumblebee species: B. (Ps.) bohemicus (Seidl.), B. (Ps.) campestris (Pz.), B. (Ps.) rupestris (F.), B. (Ps.) vestalis (Fourc.). The size of parks, percentage of area covered by trees, and characteristics of the areas surrounding the parks were found to be not significant for the diversity and abundance of bumblebees in urban parks. However, our results indicate the importance of the semi-natural areas within the parks for the species diversity.

The aim of our research was to compare the levels of pollution in different habitats based on the concentrations of heavy metals found in pollen and the organisms of Osmia bicornis L. bees in three habitats: orchards, berry plantations, and urban habitats (near by power plant, landfill, residential areas, and heavy vehicle traffic). The concentration of Ag, Cd, Cu, Fe, Mn, Ni, Pb and Zn were determined. Samples were quantified using flame atomic absorption spectrophotometry (AAS), with evaluations being carried out three times for each sample. Bee nests were also analyzed concerning reproduction and the presence of parasites. There were no significant differences in the content of heavy metals Ag, Cd, Cu, Fe, Mn, Ni, Pb and Zn in pollen samples between the three habitat types. Bee samples differed only in their Zn content, which was significantly higher in orchards (2.67 mg/kg) than urban habitats (0.80 mg/kg) and berry plantation (0.94 mg/kg). Habitat type had no effect on most bee reproductive parameters (percentage of occupied nest tubes, population growth). Our results show that bees pollinating crops in, for example orchards or berry plantations are exposed to heavy metals to a similar extent to those urban areas.

In mass production, instrumentally inseminated honey bee queens are usually kept in mailing cages with a low number of workers and inseminated with small doses of semen. Inseminated queens should have more than 4 mln sperms in their spermatheca. The aim of this study was to investigate the number of spermatozoa entering the spermatheca of queens inseminated with different small doses of semen. Ninety queens were divided into six groups and inseminated as follows: 1µl, 2µl or 3µl of semen at the age of 7 days and 2x1µl, 2x2µl or 2x3µl at the age of 7 and 9 days. Queens were kept in the mailing cages with 15 or 25 attendant bees before and after instrumental insemination. No significant differences were found in mortality and the condition of oviducts of queens inseminated with different small doses of semen and kept in cages with 15 or 25 workers. Queens inseminated with 2x2µl of semen had significantly less sperms in their spermatheca than those inseminated with 2x3µl but signifficantly more than 2x1µl and 1µl, 2µl or 3µl. The smallest dose of semen used for instrumental insemination of honey bee queens should be 2x3µl. Significant differences in the number of spermatozoa in the spematheca of queens kept with 15 or 25 attendant bees were not found.