Table_1_Effects of geographic origin and temperature on survival, development, and emergence of the managed pollinator Osmia lignaria.DOCX

IntroductionThe blue orchard bee, Osmia lignaria, is a widespread North American native pollinator that can be employed for commercial fruit and nut crop production. The largest supplies of these bees are collected in the wildlands ssssof Utah and Washington, United States. How O. lignaria from different geographic regions respond to current recommended management practices or translocation to novel environments is not fully understood.
MethodsUtah- and Washington-originated O. lignaria were reared in laboratory incubators under two thermal regimens: (1) constant temperatures used to manage bees through immature development, adult winter dormancy, and for spring emergence, and (2) hourly fluctuating temperatures programmed to mimic the natural daily (24 h) thermal cycles of the nearest cherry orchard growing region through their life cycles.
ResultsIn comparison to rearing bees at orchard temperatures, we found that rearing bees at a constant temperature increased survival and shortened egg–adult development periods. Washington bees were more adversely affected by the consistent warm rearing temperatures than were Utah bees, possibly due to their adaptations to Washington’s relatively moderate climate. At orchard temperatures, Utah bees suffered high prepupal and pupal mortality, while Washington bees suffered high pupal and adult mortality. These late life stages coincided with the hottest maximum temperatures in their respective thermal regimens. Adult females from both states naturally emerged in synchrony with local bloom time, but their emergence period overall was prolonged compared to bees in the constant thermal regimen that were induced to emerge at orchard bloom times.
DiscussionOur data support that bees originating from cool montane habitats of different U.S. states suffer from the warmer climatic conditions at lower altitudes of their respective crop-growing regions. A better understanding of optimal management temperatures for O. lignaria from different geographic regions and the effect of bee origin and temperature on survival and development timing is needed for best managing these pollinators when they are translocated or when climate change results in increased temperatures during bee development periods.

引言
蓝果园蜂（blue orchard bee, Osmia lignaria）是广泛分布于北美本土的传粉昆虫，可应用于商业化果品与坚果作物的授粉生产。该蜂的最大种群采集自美国犹他州与华盛顿州的荒野区域。目前，不同地理起源的蓝果园蜂对现行推荐管理措施，或是被迁移至全新环境后的响应机制尚未完全阐明。

材料与方法
研究将采自犹他州与华盛顿州的蓝果园蜂置于实验室培养箱中，采用两种温度制度进行饲养：（1）恒定温度模式，用于调控蜂类的幼态发育、成虫越冬休眠及春季羽化流程；（2）逐时波动温度模式，程序设置为模拟最近樱桃种植区域的自然每日（24小时）温度周期，覆盖蜂类的整个生命周期。

结果
相较于果园环境温度饲养的蜂群，本研究发现恒定温度饲养可显著提升蜂群存活率，并缩短卵至成虫的发育周期。华盛顿州种群相较于犹他州种群，受持续温暖饲养温度的负面影响更为严重，这可能与其适应华盛顿州相对温和的气候有关。在果园温度条件下，犹他州种群的预蛹期与蛹期死亡率较高，而华盛顿州种群的蛹期及成虫期死亡率偏高。上述生命后期阶段与其各自温度制度下的最高极端高温时段恰好重合。两个种群的雌性成虫均自然同步于当地花期羽化，但相较于在恒定温度制度下被调控至与果园花期同步羽化的蜂群，其整体羽化周期显著延长。

讨论
本研究数据证实，源自美国不同州凉爽山地生境的蜂群，在各自种植产区的低海拔较温暖气候条件下生存表现欠佳。为实现这类传粉昆虫在迁移饲养，或是气候变化导致其发育阶段温度升高时的最优管理，亟需进一步明确不同地理起源蓝果园蜂的最佳饲养温度参数，以及蜂群来源与温度因素对存活率和发育时序的综合影响。