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Insects provide key pollination services in most terrestrial biomes, but this service depends on a multistep interaction between insect and plant. An insect needs to visit a flower, receive pollen from the anthers, move to another conspecific flower, and finally deposit the pollen on a receptive stigma. Each of these steps may be affected by climate change, and focusing on only one of them (e.g., flower visitation) may miss important signals of change in service provision. In this study, we combine data on visitation, pollen transport, and single‐visit pollen deposition to estimate functional outcomes in the high Arctic plant‐pollinator network of Zackenberg, Northeast Greenland, a model system for global warming–associated impacts in pollination services. Over two decades of rapid climate warming, we sampled the network repeatedly: in 1996, 1997, 2010, 2011, and 2016. Although the flowering plant and insect communities and their interactions varied substantially between years, as expected based on highly variable Arctic weather, there was no detectable directional change in either the structure of flower‐visitor networks or estimated pollen deposition. For flower‐visitor networks compiled over a single week, species phenologies caused major within‐year variation in network structure despite consistency across years. Weekly networks for the middle of the flowering season emerged as especially important because most pollination service can be expected to be provided by these large, highly nested networks. Our findings suggest that pollination ecosystem service in the high Arctic is remarkably resilient. This resilience may reflect the plasticity of Arctic biota as an adaptation to extreme and unpredictable weather. However, most pollination service was contributed by relatively few fly taxa (Diptera: Spilogona sanctipauli and Drymeia segnis [Muscidae] and species of Rhamphomyia [Empididae]). If these key pollinators are negatively affected by climate change, network structure and the pollination service that depends on it would be seriously compromised. [ABSTRACT FROM AUTHOR]

Insect–plant interactions are key determinants of plant and insect fitness, providing important ecosystem services around the world—including the Arctic region. Recently, it has been suggested that climate warming causes rifts between flower and pollinator phenology. To what extent the progression of pollinators matches the availability of flowers in the Arctic season is poorly known. In this study, we aimed to characterize the community phenology of flowers and insects in a rapidly changing Arctic environment from a descriptive and functional perspective. To this end, we inferred changes in resource availability from both a plant and an insect point of view, by connecting resource and consumer species through a metaweb of all the plant–insect interactions ever observed at a site. Specifically, we: (1) characterized species‐specific phenology among plants and insects at two High‐Arctic sites—Cambridge Bay in Nunavut, Canada, and Zackenberg in Northeast Greenland; (2) quantified competition for flowers using sticky flower mimics; (3) used information on plant–pollinator interactions to quantify supply and demand for pollinator services versus flower resources during the summer; and (4) compared patterns observed within a focal summer at each site to patterns of long‐term change at Zackenberg, using a 25‐year time series of plant flowering and insect phenology. Within summers, we found evidence of a general mismatch between supply and demand. Over the 25‐year time series, the number of weeks per summer when resource supply fell below a standardized threshold increased significantly over time. In addition, variation in resource availability increased significantly over years. We suggest that the number of resource‐poor weeks per year is increasing and becoming less predictable in the High Arctic. This will have important implications for plant pollination, pollinator fitness, and the future of the Arctic ecosystem, as both plants and their pollinators are faced with widening resource gaps. [ABSTRACT FROM AUTHOR]

To associate specimens identified by molecular characters to other biological knowledge, we need reference sequences annotated by Linnaean taxonomy. In this study, we (1) report the creation of a comprehensive reference library of DNA barcodes for the arthropods of an entire country (Finland), (2) publish this library, and (3) deliver a new identification tool for insects and spiders, as based on this resource. The reference library contains mtDNA COI barcodes for 11,275 (43%) of 26,437 arthropod species known from Finland, including 10,811 (45%) of 23,956 insect species. To quantify the improvement in identification accuracy enabled by the current reference library, we ran 1000 Finnish insect and spider species through the Barcode of Life Data system (BOLD) identification engine. Of these, 91% were correctly assigned to a unique species when compared to the new reference library alone, 85% were correctly identified when compared to BOLD with the new material included, and 75% with the new material excluded. To capitalize on this resource, we used the new reference material to train a probabilistic taxonomic assignment tool, FinPROTAX, scoring high success. For the full-length barcode region, the accuracy of taxonomic assignments at the level of classes, orders, families, subfamilies, tribes, genera, and species reached 99.9%, 99.9%, 99.8%, 99.7%, 99.4%, 96.8%, and 88.5%, respectively. The FinBOL arthropod reference library and FinPROTAX are available through the Finnish Biodiversity Information Facility (www.laji.fi) at https://laji.fi/en/theme/protax. Overall, the FinBOL investment represents a massive capacity-transfer from the taxonomic community of Finland to all sectors of society., (© 2021 The Authors. Molecular Ecology Resources published by John Wiley & Sons Ltd.)