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In recent decades, many bumble bee species have declined due to changes in habitat, climate, and pressures from pathogens, pesticides, and introduced species. The western bumble bee (Bombus occidentalis), once common throughout western North America, is a species of concern and will be considered for listing by the U.S. Fish and Wildlife Service (USFWS) under the Endangered Species Act (ESA). We attempt to improve alignment of data collection and research with USFWS needs to consider redundancy, resiliency, and representation in the upcoming species status assessment. We reviewed existing data and literature on B. occidentalis, highlighting information gaps and priority topics for research. Priorities include increased knowledge of trends, basic information on several life‐history stages, and improved understanding of the relative and interacting effects of stressors on population trends, especially the effects of pathogens, pesticides, climate change, and habitat loss. An understanding of how and where geographic range extent has changed for the two subspecies of B. occidentalis is also needed. We outline data that could be easily collected in other research projects that would increase their utility for understanding range‐wide trends of bumble bees. We modeled the overall trend in occupancy from 1998 to 2018 of Bombus occidentalis within the continental United States using existing data. The probability of local occupancy declined by 93% over 21 yr from 0.81 (95% CRI = 0.43, 0.98) in 1998 to 0.06 (95% CRI = 0.02, 0.16) in 2018. The decline in occupancy varied spatially by landcover and other environmental factors. Detection rates vary in both space and time, but peak detection across the continental United States occurs in mid‐July. We found considerable spatial gaps in recent sampling, with limited sampling in many regions, including most of Alaska, northwestern Canada, and the southwestern United States. We therefore propose a sampling design to address these gaps to best inform the ESA species status assessment through improved assessment of how the spatial distribution of stressors influences occupancy changes. Finally, we request involvement via data sharing, participation in occupancy sampling with repeated visits to distributed survey sites, and complementary research to address priorities outlined in this paper.

Bumblebees (Bombus Latreille 1802) are important native pollinators in North America. However, in the last decade at least six North American Bombus have experienced significant range contraction or population declines. A major limitation to studying species declines is the level of knowledge of historic occurrences and abundance. Here we review the current status of a bumblebee subgenus in North America, Bombus sensu stricto Latreille 1801, and present a method for generating a database and probable historic range maps from multiple museum collections. These databases and range maps can be useful tools when facilitating monitoring programs for at risk species. Buradaki derleme ile Kuzey Amerika örneği olan Bombus s. str. altcinsine ait bilgi birikiminin aktarılması ve entomoloji koleksiyonlarındaki örnekleri kullanılarak tür veritabanları oluşturma metodunun sunulması amaçlanmıştır. Bombus arıları Kuzey Amerika’da bulunan hem yabani çiçekleri hem de tarımsal ürünleri tozlaştıran balarısı gibi diğer tozlaştırıcıların olmadığı yerlerdeki en önemli tozlaştırıcılardan birisidir. Geçen on yıllık dönemde en azından altı Kuzey Amerika bombus arısı (Bombus Latreille 1802) türü önemli anlamda yayılma alanının daralması ya da populasyon azalması ile karşı karşıya bulunmakta ve bunlardan birinin (Bombus franklini Franklin 1921) soyu tükenmiş te olabilir.