Diversity and management of bees for the pollination of apple in the Annapolis Valley of Nova Scotia

This thesis is an investigation of several aspects of apple pollination in the Annapolis Valley of Nova Scotia. For one aspect, bee diversity in the province was determined, including a comparison of species richness in orchard and natural systems. Over 200 bee species are in Nova Scotia; almost 60 species newly recorded for the province during this study. A small proportion of these (ca. < 25%) have been recorded on apple flowers in Nova Scotia; even fewer contribute significantly to apple pollination.; The habitats surrounding apple orchards have significant impacts on the respective bee fauna. For cavity-nesting bee species, lack of nesting sites is the main factor limiting species richness, but trap-nests within orchards can increase diversity to levels observed in natural habitats. As most managed non-Apis apple pollinators are bees of the genus Osmia (Megachilidae), this finding is encouraging for Nova Scotian apple growers. However, orchards with natural borders support higher bee species diversity and abundance than those with agricultural borders. The resulting abundance and diversity of food plants and nesting sites are the most important factors affecting bee community structure in these habitats overall.; A second component of this study examined the requirements of managed apple pollinators, specifically food plant availability and winter management options---Osmia lignaria (Megachilidae), served as a model pollinator. Lupines (Lupines polyphyllus) proved ideal as an additional food plant, as supported by flowering phenology overlap and pollen use, accounting for over 80% of that collected following apple flowering. Nesting bee populations adjacent to lupine plots had significantly higher population growth than those isolated from the plots. Wintering populations of O. lignaria in unheated albeit sheltered areas proved slightly but significantly better than wintering bees within climate controlled cabinets. The economic benefits and potential risks of these two options are compared.; Lastly, a study was conducted to determine if apple flowers were imperfectly syncarpic (i.e., pollination of one stigma results in fertilization within one carpel only), as believed by most pomologists. Both hand pollination studies and microscopic analysis of apple flowers supported perfect, not imperfect, syncarpy. Implications of this finding with respect to fruit production are discussed.