-The influence of different diets on the haemolymph of adult honeybee workers was examined. The laboratory experiments took place in early summer. There were three experimental groups fed with one of the following diets: pollen with sugar, pollen substitute alone, or sugar. A sample of haemolymph was taken from 7-8 day old bees and numbers of haemocytes of each type (plasmatocytes, granular haemocytes, and other types of haemocytes pooled together) were recorded and the metabolic activity of haemocytes was observed. A lack of protein caused a significant increase in the percentage of granular haemocytes, a significant decrease of other types and a lower metabolic activity. The examined pollen substitute caused a decrease of total haemocyte count. The decrease in the metabolic activity of haemocytes was lower than without protein.Apis mellifera / diet / haemocyte / adult worker

2005) The effects of probiotic supplementation on the content of intestinal microflora and chemical composition of worker honey bees (Apis mellifera), Journal

The aim of this investigations was to assess morphological changes in the midgut epithelium of bees nourished with pollen substitute or pollen substitute enriched with a probiotic preparation. One-day old worker bees were kept in cages placed in a temperature controlled environment. During the two-week feeding period workers were fed beebread (control), pure pollen substitute or pollen substitute fortified with three different doses of probiotic preparations: Biogen or Trilac (experimental groups). The assessment of histological changes of the bee midgut was carried out in bees feed for 8 and 14 days. Slight changes in the epithelium as well as strong merocrine-type secretion were recorded in bees nourished pollen substitute supplemented with probiotic preparations. Differences were observed, primarily, in quantities of the developed peritrophic membranes. Their quantities were particularly high after 14 days of feeding with the pollen substitute fortified with probiotic preparations. The development of numerous peritrophic membranes could have contributed to better utilization of nutrients contained in feed and better condition of bees.

Red mason bee Osmia bicornis (L.) is a solitary bee which has been shown to be a successful pollinator of many field crops and greenhouse crops. In favorable environmental conditions, this solitary bee can significantly raise the efficiency of crops. Controlled honeybee farms are invaded by various accompanying fauna. The aim of the study was to find out if the biotope may increase or limit the presence of foreign fauna in the nests of the solitary bee O. bicornis (L.). Four different biotopes were selected: a traditional orchard, the dendrological park of the Polish Academy of Sciences in Kórnik, a mixed forest, and a haymeadow, where artificial aggregations of O. bicornis (L.) were made, with 300 specimens in each. They were given artificial nests of common reed. The nests were then analysed after the end of the brooding period. The number of brood chambers built by females was determined. The number of chambers where the forms of development stopped at the egg or larva stage, the number of parasite-invaded chambers, and the systematic membership of the encountered foreign fauna, was also determined. The analysis of variance and Duncan's test with the significance level of α=0.05 proved that the biotope influenced the development of the O. bicornis (L.) population. The females in the forest biotope built the most brood chambers in each tube on average, and the result was significantly different from the other biotopes. The largest number of larvae died in the nests which had been placed in the dendrological park, and that value was also statistically different from the others. The highest parasite invasion was noted in the nests situated in the forest.

Osmia rufa L. (Osmia bicornis L.) is a species of a solitary bee, which pollinates many wild and cultivated plants. A total of 900 cocoons containing mature individuals of Osmia rufa L. (450 females and 450 males of a known weight), were placed in each of four habitats (orchard, mixed forest, hay meadow and arboretum of the Dendrology Institute of the Polish Academy of Sciences at Kórnik). These bees were provided with artificial nests made of the stems of common reed. The following parameters were calculated: reproduction dynamics, total number of chambers built by females, mean number of breeding chambers per reed tube and mean number of cocoons per tube. included in the analysis were also the nectar flowers and weather conditions recorded in each of the habitats studied. General linear mixed models indicated that the highest number of chambers was recorded in the hay meadow (6.6 per tube). However, the number of cocoons per tube was similar in the hay meadow, forest and orchard (4.5-4.8 per tube) but was significantly lower in the arboretum (3.0 cocoons per tube on average). also, the highest reproduction coefficient, 317.5%, was recorded in the hay meadows. Some nests were also parasitized and the highest mean number of infected chambers per tube (0.68) was recorded in the forest. The number of chambers was positively related to temperature. These results indicate that habitat had a significant effect on the reproduction of the red mason bee.