|Kemp, William - Bill|
Submitted to: Workshop Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/26/2004
Publication Date: N/A
Citation: Interpretive Summary: The blue orchard bee, Osmia lignaria, is being developed as a manageable orchard pollinator throughout North America. Adults of this species are active in the spring, building and provisioning nests with brood, and provide outstanding pollination for early flowering tree fruit crops including almonds, apples, sweet cherries, plums, and pears. In this article, we provide a detailed account of the annual lifecycle of this solitary bee and describe critical, yet simple, management activities that will yield healthy pollinator populations that are active when the target orchard crop is in bloom each spring. This article updates previous publications on the management of the blue orchard bee with results distilled from several recently published studies by the authors. The contents of this article were presented by invitation at the 'International Workshop on Solitary Bees and Their Role in Pollination,' Ceará, Brazil, 26-29 April, 2004.
Technical Abstract: The solitary bee Osmia lignaria has been developed as a manageable orchard pollinator in North America. Adult O. lignaria are active in the spring, building and provisioning nests. By early summer, eggs laid during the current year complete development to fifth instars which spin cocoons and enter an apparent dormant stage. Pupation occurs by late summer, followed by adult eclosion within one month. Enclosed adults remain in their cocoons for the winter, and emerge in the spring as temperatures increase. Thus, O. lignaria are univoltine and winter in the adult stage. Respiration rates indicate that O. lignaria undergoes two diapausing periods, one in the prepupal stage in the summer, and another in the adult stage during autumn and winter. Exposure to warm and/or fluctuating temperatures is required for summer diapause completion. Exposure to cold temperatures is necessary to complete winter diapause. The timing between adult eclosion and the onset of winter temperatures is critical to O. lignaria survival. Pre-wintering adults exposed to warm temperatures for too long use up their fat body reserves, loose weight and vigor and are more likely to die during the winter. In this study, we discuss the implications of these results for the establishment of appropriate rearing methods for O. lignaria populations used in orchard pollination.