Verhaltensbiologie und Didaktik der Biologie

Side effects of neonicotinoid insecticides on bumble bees


    Sadaf Ghasemimoakher


    Pollinators play an important role in global food production and in maintaining wild plant communities. Bees like honeybees, bumble bees and solitary bees are the prominent and economically most important group of pollinators worldwide. Bumble bees are important for the pollination of many wild flowers and are crucial for the terrestrial ecosystem. They are also important pollinators of high value agricultural crops and allow plants to reproduce and improve the production of crops, such as tomato, pepper and many other types of fruits, vegetables and seeds that make up our diet. Wild bees' populations are declining at a global scale. Given the economic and ecological importance of pollinating insects, an understanding of the underlying causes of these declines is vital. Several factors such as habitat loss, parasites, diseases and pesticides have been lead to decline the bees. However, current knowledge of pesticide toxicity on pollinating insects is fragmented for bumblebees since it is still mostly restricted to honey bees. Neonicotinods like imidicloprid, clothianidin and thiamethoxam are widely used systemic pesticides and known to affect bees as non- target insects therefore effects of pesticides need to be assessed for conservation and economic reasons.

    The purpose of my study is to investigate the side effect of neonicotinoids on bumblebees' nervous system and behavior; I will focus on the effect of lethal and sub-lethal doses on behavioral adaption, physiological function and gene expression in bumblebees. In the field the bees will be exposed to sub-lethal doses and the homing behavior will be surveyed. In behavioral laboratory experiment, effects on learning performance will be studied by means of proboscis extension reflex. In the next step the effect of lethal and sub-lethal doses will be examined on the level of physiological function. I will investigate the effect of neonicotinoids on the acetylcholin receptor in the bumble bees' brain. In addition, I will investigate whether exposure causes alterations in AChE gene transcription in the bumble bees' brain.

    With this study I will be able to estimate the effect of these pesticides on bumble bees in sub-lethal level. The results of the work will be useful for agricultural and economical system.