Abstract:
Interactions between pesticides and parasites are
believed to be responsible for increased mortality of
honey bee (Apis mellifera) colonies in the northern
hemisphere. Previous efforts have employed experimental
approaches using small groups under laboratory
conditions to investigate influence of these
stressors on honey bee physiology and behaviour,
although both the colony level and field conditions
play a key role for eusocial honey bees. Here, we
challenged honey bee workers under in vivo colony
conditions with sublethal doses of the neonicotinoid
thiacloprid, the miticide tau-fluvalinate and the endoparasite
Nosema ceranae, to investigate potential
effects on longevity and behaviour using observation
hives. In contrast to previous laboratory studies, our
results do not suggest interactions among stressors,
but rather lone effects of pesticides and the parasite
on mortality and behaviour, respectively. These
effects appear to be weak due to different outcomes
at the two study sites, thereby suggesting that the role of thiacloprid, tau-fluvalinate and N. ceranae and
interactions among them may have been overemphasized.
In the future, investigations into the effects of
honey bee stressors should prioritize the use of colonies
maintained under a variety of environmental conditions
in order to obtain more biologically relevant
data.
