Bee ecology and evolution in the context of global change

蜜蜂是许多农作物和野生植物授粉的关键，但关于世界上约20,000种野生蜜蜂，仍有许多未知之处。由于缺乏信息，很难知道野生蜜蜂将如何应对气候变化和物种引进等挑战--更不用说提出知情的管理建议了。我的研究计划将对蜜蜂有新的发现，同时解决昆虫生态学和进化生物学的基本问题，并在有价值的领域、实验室和沟通技能方面培训学生。在接下来的五年里，我们将解决三个目标：1.为了了解气候变化如何影响美国西南部的独居蜜蜂种群，那里的干旱严重程度正在加剧，我们将建立在我的实验室现有的关于蜜蜂繁殖、花朵丰度和温度的5年多地点数据集的基础上。我们将评估蜂巢蜜蜂的繁殖产出如何因蜜蜂出现的时间相对于开花时间的变化而受到影响，以及干旱对花蜜和花粉可用性的影响。我们还将测量蜂巢内的温度，并测试较暖的温度是否允许蜜蜂寄生虫相对于它们的宿主加速发育。2.为了了解限制野生蜜蜂地理范围的因素，我们将研究北美东北部和落基山脉的独居蜜蜂，询问北部或高海拔范围的限制是由温度、花卉寄主植物的丰富性、季节长度或蜜蜂活动期和开花之间的重叠程度决定的。这些研究将帮助我们预测蜜蜂范围将如何应对气候变化和不同开花时间的非本土植物物种的到来。3.我们将重新评估蜜蜂和植物之间的共同进化如何导致蜜蜂多样性。蜜蜂通常被视为对植物有益，但作为花粉消费者，它们与植物的关系也是敌对的。事实上，许多植物的花粉含有防御性化学物质，这表明植物保护它们的花粉；相反，某些蜜蜂专门研究看似防御性的花粉类型，这表明它们已经进化成了克服防御的能力。我们将对专业和通才蜂种的花粉使用情况进行实地观察，综合公民科学数据，并进行实验室实验，测试(A)专业和通才蜜蜂使用不同花粉的能力，以及(B)不同花粉抵抗蜜蜂真菌病原体感染的能力。这些研究将为蜜蜂为何专攻某些类型的花粉的假说提供第一次测试。这一结果将帮助我们预测新获得的花粉类型何时会被纳入蜜蜂的饮食中，并就哪些植物应该包括在对传粉者友好的花园中提出更好的建议。总体而言，这项研究将为野生蜜蜂的进化史以及它们在快速变化的世界中的未来提供新的见解。

Bees are crucial for pollination of many crops and wild plants, yet much remains unknown about the world's ~20,000 wild bee species. The lack of information makes it difficult to know how wild bees will respond to challenges such as climate change and species introductions-let alone make informed management recommendations. My research program will make new discoveries about bees while addressing fundamental questions in insect ecology and evolutionary biology and training students in valuable field, laboratory, and communication skills. In the next five years, we will address three goals: 1. To understand how climate change is affecting solitary bee populations in the southwestern U.S., where drought severity is increasing, we will build on my lab's existing 5-year, multi-site dataset on bee reproduction, flower abundance, and temperature. We will assess how reproductive output of cavity-nesting bees is affected by shifts in the timing of bee emergence relative to flowering time, and by effects of drought on nectar and pollen availability. We will also measure temperatures inside bee nests and test whether warmer temperatures allow bee parasites to accelerate development relative to their hosts. 2. To understand the factors that limit geographic ranges of wild bees, we will study solitary bees in northeastern North America and the Rocky Mountains, asking whether northern or upper-elevation range limits are determined by temperature, abundance of floral host-plants, season length, or the extent of overlap between bee activity periods and flowering. These studies will help us predict how bee ranges will respond to climate change and arrival of non-native plant species with differing flowering times. 3. We will re-evaluate how coevolution between bees and plants has given rise to bee diversity. Bees are normally viewed as beneficial to plants, but as pollen consumers, their relationship with plants is also adversarial. Indeed, pollens of many plant species possess defensive chemicals, suggesting that plants protect their pollen; conversely, certain groups of bees specialize on seemingly defended pollen types, suggesting that they have evolved to overcome the defences. We will conduct field observations of pollen usage by specialist and generalist bee species, syntheses of citizen-science data, and laboratory experiments testing (a) abilities of specialist and generalist bees to use different pollens, and (b) abilities of different pollens to resist infection by fungal pathogens of bees. These studies will provide the first tests of hypotheses for why bees specialize on certain pollen types. The results will help us predict when newly available pollen types will be incorporated in bee diets and make better suggestions about which plants to include in "pollinator-friendly" gardens. Overall, this research will provide novel insights into the evolutionary history of wild bees as well as their future in a rapidly changing world.