The long-term decline of wild and managed insect pollinators is a threat to both agricultural output and biodiversity, and has been linked to decreasing floral resources. Further insight into the temporal relationships of pollinators and their flowering partners is required to inform conservation efforts. Here we examined the phenology of British: (i) pollinator activity; (ii) insect-pollinated plant flowering; and (iii) extinct and endangered pollinator and plant species. Over 1 million records were collated from the historical databases of three British insect monitoring organisations, a global biodiversity database and an authoritative text covering the national flora. Almost two-thirds (62%) of pollinator species have peak flight observations during late-summer (July and August). This was the case across three of the groups studied: aculeate wasps (71% of species), bees (60%), and butterflies (72%), the exception being hoverflies (49%). When species geographical range (a proxy for abundance) was accounted for, a clear late-summer peak was clear across all groups. By contrast, there is marked temporal partitioning in the flowering of the major plant groups: insect-pollinated tree species blossoming predominantly during May (74%), shrubs in June (69%), and herbs in July (83%). There was a positive correlation between the number of pollinator species on the wing and the richness of both flowering insect-pollinated herbs and trees/shrubs species, per calendar month. In addition, significantly greater extinctions occurred in late-summer-flying pollinator species than expected (83% of extinct species vs. 62% of all species). This trend was driven primarily by bee extinctions (80% vs. 60%) and was not apparent in other groups. We contend that this is principally due to declines in late-summer resource supplies, which are almost entirely provisioned by herbs, a consequence of historical land-use change. We hypothesize that the seasonality of interspecific competition and the blooming of trees and mass-flowering crops may have partially buffered spring-flying pollinators from the impacts of historical change.

中文翻译：

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英国物候记录表明晚夏传粉昆虫的多样性和灭绝率很高

野生和受管理昆虫传粉者的长期减少对农业产量和生物多样性构成威胁，并与花卉资源减少有关。需要进一步了解传粉媒介及其开花伙伴的时间关系，以便为保护工作提供信息。在这里，我们检查了英国的物候：（i）传粉媒介活动；(ii) 昆虫授粉植物开花；(iii) 已灭绝和濒临灭绝的传粉媒介和植物物种。从三个英国昆虫监测组织的历史数据库、一个全球生物多样性数据库和一份涵盖国家植物群的权威文本中整理了超过 100 万条记录。几乎三分之二 (62%) 的传粉媒介物种在夏末（7 月和 8 月）有飞行观察高峰。在研究的三个组中都是这种情况：有刺黄蜂（71% 的物种）、蜜蜂（60%）和蝴蝶（72%），食蚜蝇除外（49%）。当考虑到物种地理范围（丰度的代表）时，所有组都出现了明显的夏末高峰。相比之下，主要植物群的开花时间划分明显：昆虫授粉树种主要在 5 月开花（74%），灌木在 6 月开花（69%），草本在 7 月开花（83%）。每个日历月，翅膀上传粉媒介物种的数量与开花昆虫授粉草本植物和树木/灌木物种的丰富度之间存在正相关关系。此外，夏末飞行的传粉媒介物种的灭绝比预期的要大得多（灭绝物种的 83% 对所有物种的 62%）。这种趋势主要是由蜜蜂灭绝（80% 与 60%）驱动的，在其他群体中并不明显。我们认为，这主要是由于夏末资源供应的减少，几乎完全由草药提供，这是历史土地利用变化的结果。我们假设种间竞争的季节性以及树木和大量开花作物的开花可能部分缓冲了春季传粉媒介免受历史变化的影响。