Pollen specialization is associated with later phenology in Osmia mason bees (Hymenoptera: Megachilidae)

1. Species exhibit a range of specialisation in diet and other niche axes, with specialists typically thought to be more efficient in resource use but more vulnerable to extinction than generalists. Among herbivorous insects, dietary specialists seem more likely to lack acceptable host plants during the insect’s feeding stage, owing to fluctuations in host-plant abundance or phenology. Like other herbivores, bee species vary in host breadth from pollen specialisation (oligolecty) to generalisation (polylecty).
2. Several studies have shown greater interannual variation in flowering phenology for earlier-flowering plants than later-flowering plants, suggesting that early-season bees may experience substantial year-to-year variation in the floral taxa available to them.
3. We therefore reasoned that, among bees, early phenology could be a more viable strategy for generalists, which can use resources from multiple floral taxa, than for specialists. Consequently, we expected median dates of...

1. 各类物种在饮食与其他生态位轴上展现出各异的特化程度，学界通常认为专食类群在资源利用效率上更具优势，但相较于广适类群更易濒临灭绝。在植食性昆虫中，由于寄主植物的丰度或物候发生波动，专食性类群往往更可能在昆虫取食阶段缺乏适宜的寄主植物。与其他植食动物类似，蜂类的寄主广度同样存在差异，从花粉专食性（oligolecty）到广食性（polylecty）不等。
2. 多项研究已表明，相较于晚开花植物，早开花植物的开花物候存在更大的年际波动，这意味着早期活动的蜂类可能会面临其可利用花类类群逐年发生显著变化的情况。
3. 因此我们推测，在蜂类类群中，相较于专食性物种，可利用多种花类类群资源的广适性物种采取早期活动的生存策略将更具可行性。据此我们预期，median dates of...