Suspected poisoning of honeybees in England and Wales is investigated by the Wildlife Incident Investigation Scheme (WIIS). Cases of suspected poisoning are only accepted into WIIS if there are grounds for suspecting the involvement of pesticides. In recent years, there has been an increase in the number of cases accepted into WIIS (12 cases in 2005 and 2006 compared to 38 in 2009, 22 in 2010 and 18 in 2011). In addition, improved methods in use in WIIS in recent years have resulted in a higher number of detections of low levels of multiple pesticides in honeybee samples than has previously been the case (see PS2368). Recently there is increasing interest in the interactions between pesticides and disease, i.e. is disease incidence, such as Nosema, greater in colonies exposed to pesticides (Alaux et al 2010, Vidau et al 2011, Pettis et al 2012, Wu et al 2012).
Many of these pesticide residues are at low levels (sub- ng) and it is likely that they are not associated with any effects on honeybees. However there is little scientific information on which to base the interpretation of the significance of these residues in honeybees. Monitoring data from France (Chauzat et al 2011) shows pesticide residues in live bees but data on multiple residues in samples from single colonies are not available and there is no data on disease incidence within these colonies. This project aims to collect samples of adult honeybees foragers from colonies in both urban and rural environments, assess the pesticide residues present in these apparently healthy colonies and the associated adult bee diseases (acarine, Nosema and viruses) in the same samples. Samples will be taken at the time when pesticide exposure is likely, when main crops are flowering. Follow-up assessments will be undertaken in the autumn and following spring, with samples taken for repeat adult disease analysis in the autumn, to provide information on colony health status.