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Studies were carried out in 2004-2007 in two apiaries which varied in flow terms. In the midsummer, bees from P apiary collected pollen and nectar from mixed forest, pastures and fields, while bees from NJ apiary worked white mustard and weeds on wastelands. The winter scatters were collected for investigations every year, after the first bees’ flight. HCH concentration in bees from P apiary ranged from 0.00102 μg/g of lipid matter (l.m.) to 0.00170 μg/g l.m. and the total amount of DDT was 0.00970-0.03530 μg/g l.m. In the bees’ scatter from NJ apiary the HCH level was 0.00091-0.00530 μg/g l.m. and the total amount of DDT was 0.00171-0.00424 μg/g l.m. Between 2004 and 2007 the level of chlorinated hydrocarbons, mostly HCH, in both apiaries (especially in NJ) was reduced. It shows a progressive decomposition of this compound in the environment. However, the DDT content in the scatter from P apiary in the first two years of investigations as well as in 2007 was 0.00970-0.01280 μg/g l.m., whereas in 2006 it increased up to 0.03530 μg/g l.m. So significant an increase (2.7-3.6 times) in the DDT content towards the end of the investigated period seems to indicate a periodical infiltration of this compound into the region of the Pisz forest, probably from Africa, where this pesticide is still applied for mosquito control.
The aim of the study was to determine the influence of Varroa destructor invasions on HCH and DDT concentration in bees from infected colonies. Studies were carried out on 7 apiaries in the Olsztyn area. It was found that HCH and DDT content in bees depended on both apiary location and V. destructor presence in colonies. Bees from infected colonies contained less amounts of chlorinated hydrocarbons. The greatest concentration of HCH and DDT was found in bees from apiaries located on the verge of forests, near allotment gardens, and the least in bees flying around rape, white mustard and weeds on waste ground. Higher HCH and DDT concentrations in bees free from V. destructor invasion indicates their greater activity in the environment and bringing flow to the hive, the amount of which influences the increase of chlorinated hydrocarbons in the organism.
The aim of investigations was to estimate the influence of consumed pollen in colonies infected with Varroa on the concentration of chlorinated hydrocarbons in bees. Studies were carried out in September in 4 apiaries, from which approximately 300 bees were collected from the randomly chosen colonies. The midgut from 10 insects was isolated and pollen grains were counted. The remaining insects served for the estimation of the level of chlorinated hydrocarbons and Varroa infection. In bee samples only residues of HCH and DDE were found. In the presence of 3.1-3.2 pollen grains in the microscope eyeshot, the HCH and DDE content was the lowest, and it was the highest in the presence of 22.8-37.5 pollen grains. In the other colonies with similar numbers of pollen grains and considerable differences in bee infection with Varroa (about 8 times), the HCH and DDE concentration was respectively: 25 and 13 units higher than in bees with a lesser extensiveness of invasion. In the next apiary, where the number of pollen grains fluctuated between 4.4-4.8 and the invasion extensiveness was 5.95% and 15.4%, the concentration of both pesticides was lower than in the previous one. Similar differences in HCH and DDE levels occurred in bees in which in the ground abdomens were found 10.4 and 22.8 pollen grains. In bees with marginal Varroa infection (0.7%) and the greatest number of pollen (37.5), the concentration of HCH and DDE was respectively: 0.00293 µg/g l.m. and 0.00312 µg/g l.m, and it was the highest in comparison to bees from previous apiaries. The results indicate that bees from highly infected with Varroa destructor colonies consume less protein food than from faintly infected ones.
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