Results of colony loss monitoring in Scotland for the winters of 2007-2008 to 2011-2012

Gray, Alison and Peterson, Magnus (2012) Results of colony loss monitoring in Scotland for the winters of 2007-2008 to 2011-2012. In: Proceedings of COLOSS WG 1 Workshop Monitoring of colony losses 2011-2012 - temporal and spatial patterns. UNSPECIFIED, Poland, p. 10.

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    Abstract

    We began surveys of beekeepers in Scotland in 2006, using a geographically stratified approach and postal questionnaires. These have run in 2006, 2008, 2010, 2011 and 2012, with annual surveys beginning in 2010. In 2006 questions on colony loss related to unexplained losses. Since 2008 we have asked about any losses and have used stratified random sampling. We have recently examined winter loss rates based on our strata, using two different broad geographical splits, i.e. North-Central-South and East-West. These are of interest in relation to presence/absence of Varroa infestation, and different forage sources, both of which may have an association with loss rates. For the winters of 2009-2010 onwards, striking and statistically significant differences have been observed between winter loss rates between beekeepers in the east and the west of Scotland. Loss rates in the east are consistently higher. There was no significant difference in loss rates prior to that winter, and it appears that something changed between 2007-2008 and 2009-2010. Differences between the north, central Scotland and the south were not significant. Important management practices such as supplementary feeding going into winter, and Varroa treatment are unlikely to differ systematically between such large scale geographical areas, although they will differ between beekeepers. Considering possible reasons for the observed differences between areas, we are looking for factors that affect all or a large proportion of beekeepers in a given area. In Scotland two factors which have changed in recent years are the growing of Oil Seed Rape and its treatment, and also weather patterns. Examination of winter loss rates amongst beekeepers whose bees forage on OSR and those whose bees do not showed the loss rates in the former group to be significantly higher. The growing of OSR is strongly associated with area, and is much more common in the east of Scotland than the west. Investigation of possible risk factors associated with the different loss rates is ongoing