Overwintering management of Os mi a lignaria 



JESO Volume 139, 2008 



WINTER MANAGEMENT OPTIONS FOR THE ORCHARD 

 POLLINATOR OSMIA LIGNARIA SAY (HYMENOPTERA: 

 MEGACHILIDAE) IN NOVA SCOTIA 



C. S. SHEFFIELD 1 , S. M. WESTBY 2 , P. G. KEVAN 3 , R. F. SMITH 2 

 Department of Biology, York University 

 4700 Keele St., Toronto, Ontario, Canada M3J 1P3 

 email: corys@yorku.ca 



Abstract J. ent. Soc. Out. 139: 3-18 



The Blue Orchard Bee, Osmia lignaria Say, a commercially available solitary 

 bee, was recently introduced into the Annapolis Valley of Nova Scotia for 

 assessment as a manageable pollinator of apple. An important component 

 of this assessment was to investigate options for wintering this species as 

 few apple growers have storage facilities suitable for the recommended 

 wintering practices. Specifically, winter survival under ambient outside, 

 albeit sheltered conditions was compared to wintering bees in controlled 

 environmental chambers at 4°C. In addition, a comparison of survival was 

 made between bees from two populations; one introduced into Nova Scotia 

 the previous year and reared for a complete generation versus one reared in 

 Utah and imported to Nova Scotia as dormant un-emerged adults. 



Populations wintered outside fared slightly but significantly better than those 

 wintered inside, but each location proved suitable for wintering. Bees from 

 both populations had high survival (as measured by emergence from natal 

 cocoons), but rates were significantly greater in bees reared in Nova Scotia 

 for one year. Overall, bees from both populations proved suitably cold hardy 

 for wintering in Nova Scotia, as evidenced by both high rates of survival and 

 by enhanced supercooling capacity. Wintering bees in controlled conditions 

 offers the advantages of predictable climate, and controlled synchrony of 

 emergence with crop flowering. However, access to and/or lack of climate 

 controlled facilities may be a limiting factor in adopting this species for 

 commercial use in the province. This study thus provides evidence that bees 

 wintered outside have natural emergence coinciding favourably with apple 

 flowering, and that placing nests in sheltered outdoor environments in Nova 

 Scotia provides an affordable and safe approach for wintering O. lignaria 

 populations for apple pollination. 



Published November 2008 



1 Author to whom all correspondence should be addressed. 



2 Agriculture and Agri-Food Canada, 32 Main St., Kentville, NS, B4N 1 J5 



3 Department of Environmental Biology, University of Guelph, Guelph, ON, NIG 2W1 



3 



