Bumblebees and neonicotinoids: a bioassay to evaluate sublethal effects on the foraging behaviour.

To date Bombus terrestris bumblebees are worldwide introduced for the pollination of greenhouse crops such as tomatoes and strawberries. In practice these crops are under constant attack of pest and plant pathogens and thus growers need to apply pesticides in order to protect or to limit damage. Consequently it is not unlikely that bumblebee workers are exposed to these products while foraging on these crops. Pesticides may cause mortality and also sublethal effects which are not always directly visible. For example, impairment of the foraging behavior is detrimental for the colony and results in loss of crop pollination.
In this study, we report on the development of a laboratory bioassay by use of queenless micro-colonies (5 workers) to assess the impact of sublethal concentrations on the bumblebee foraging behavior. In brief, the experimental setup of this behavior test consists of two artificial nests connected with a tube of about 20 cm. In one nest the worker bees constructed brood, and in the other food (sugar and pollen) was provided. Before exposure, the worker bees were allowed a training to forage for untreated food; afterwards this was replaced by treated food. Using this setup we investigated the effects of sublethal concentrations of imidacloprid, known to negatively affect the foraging behavior of bees. For validation, the sublethal concentrations of imidacloprid were also exposed under greenhouse conditions to queenright colonies of B. terrestris and here workers needed to forage/fly for food that was placed at a distance of 3 meter from their hives.

Jaar van publicatie:2010

Trefwoorden:bumblebee, Bombus terrestris, foraging behavior