Ábrahám Levente (szerk.): Válogatott tanulmányok 13. - Natura Somogyiensis 28. / Miscellanea 13. (Kaposvár, 2016)
Sándor A.–Csikász T-Farkas S.–Rácz T.–Sárospataki M.: Preliminary semi-field study ont he effect of the neonicotinoid containing seed dressings to honeybees as pollinator in sunflower
38 Natura Somogyiensis 600 <u XI E 3 100 ■ 531 ■ 402 ■ 242 ■ 442 ■ 419 ■ 336 0 0 100000 200000 300000 400000 500000 600000 700000 800000 900000 Number of fertilized flowers on the isolated area (pcs) Fig. 2: The correlation between the number of fertilized flowers and the sum of dead bees in tents No. 23-33 (R2=0.141) Discussion The extremely high number of individuals collected during the measurements (100 bces/day is a normal die-off rate (Wilson et al. 1980)) — 19.657 adults - also confirmed our hypothesis that in addition to the natural effects in the test-tents there is prevailed other negative impacts too. The detection of strong Nosema infection of the sample collected by the 1st showing time (tent No. 1-21) given a potential explanation for the observed phenomenon, which could be one inherent of the poisoning of neonicotinoid seed treatment (Higes et al. 2008). The difference between the numbers of 07.12., 07.19. and 07.25 are attributable to the gradual drug-accumulation beside the reserve nutrient in the hive. The bees have taken up by gathering progressively the ingredients from the flowers, which have weaken their immune system made them more susceptible to the Nosema infection. On the basis of the results it can be stated that the symptoms, known from the literature, required about two weeks to appear in semi-field conditions (K irschner et al. 1998, Brunner et al. 2001, Suchail et al. 2001, Salerno et al. 2002, Singh et al. 2004, Laurino et al. 2010). Based on Table 2 we can conclude that for the quantity of bee mortality in the case of sunflowers dressed neonicotinoid treated seed dressing among others it may be held responsible the genotype of the sown sunflower, both the maternal and the restorer line. Bees visited some types intensively (they “liked their taste” more) than others, although only parental couples were different. As shown well, the mortality of the more bee-preferred types were higher than those where for example the maternal line was different. Based upon results of statistical tests found that the more nectar and pollen were consumed the bees, the higher mortality appeared, at least in the case of the tents of the first sowing time (Fig. 1). In case of the tent No. 27-33. it is not seen this kind of context therefor because they have been treated against Nosema and contained only maternal line. The experienced rate of mortality is still exceeds the expected number (2372 indi
