Bumblebee Populations Research Articles

Gut microbiome drives individual memory variation in bumblebees

The potential of the gut microbiome as a driver of individual cognitive differences in natural populations of animals remains unexplored. Here, using metagenomic sequencing of individual bumblebee hindguts, we find a positive correlation between the abundance of Lactobacillus Firm-5 cluster and memory retention on a visual discrimination task. Supplementation with the Firm-5 species Lactobacillus apis, but not other non-Firm-5 bacterial species, enhances bees’ memory. Untargeted metabolomics after L. apis supplementation show increased LPA (14:0) glycerophospholipid in the haemolymph. Oral administration of the LPA increases long-term memory significantly. Based on our findings and metagenomic/metabolomic analyses, we propose a molecular pathway for this gut-brain interaction. Our results provide insights into proximate and ultimate causes of cognitive differences in natural bumblebee populations.

Does agri-environment scheme participation in England increase pollinator populations and crop pollination services?

Agri-environment schemes are programmes where landholders enter into voluntary agreements (typically with governments) to manage agricultural land for environmental protection and nature conservation objectives. Previous work at local scale has shown that these features can provide additional floral and nesting resources to support wild pollinators, which may indirectly increase floral visitation to nearby crops. However, the effect of entire schemes on this important ecosystem service has never previously been studied at national scale. Focusing on four wild pollinator guilds (ground-nesting bumblebees, tree-nesting bumblebees, ground-nesting solitary bees, and cavity-nesting solitary bees), we used a state-of-the-art, process-based spatial model to examine the relationship between participation in agri-environment schemes across England during 2016 and the predicted abundances of these guilds and their visitation rates to four pollinator dependent crops (oilseed rape, field beans, orchard fruit and strawberries). Our modelling predicts that significant increases in national populations of ground-nesting bumblebees and ground-nesting solitary bees have occurred in response to the schemes. Lack of significant population increases for other guilds likely reflects specialist nesting resource requirements not well-catered for in schemes. We do not predict statistically significant increases in visitation to pollinator-dependent crops at national level as a result of scheme interventions but do predict some localised areas of significant increase in bumblebee visitation to crops flowering in late spring. Lack of any significant change in visitation to crops which flower outside this season is likely due to a combination of low provision of nesting resource relative to floral resource by scheme interventions and low overall participation in more intensively farmed landscapes. We recommend future schemes place greater importance on nesting resource provision alongside floral resource provision, better cater for the needs of specialised species and promote more contiguous patches of semi-natural habitat to better support solitary bee visitation.

Spatial and temporal patterns of genetic diversity in Bombus terrestris populations of the Iberian Peninsula and their conservation implications

The bumblebee Bombus terrestris is used worldwide for crop pollination. Despite its positive impact on crop yield, it has become a widespread threat to biodiversity due to its interactions with local bumblebee populations. Commercial subspecies introduced to the Iberian Peninsula since the 1990s without any regulation have colonized the environment, with evidence of naturalization and introgression with the endemic subspecies Bombus terrestris lusitanicus. We have used mitochondrial and nuclear genetic data to describe the current genetic diversity of the Iberian population and to estimate the expansion of commercial bumblebees. Samples from the natural distribution range of the commercial subspecies, the natural intergradation area between the two subspecies and from a period prior to the use of commercial colonies (i.e., before the 1990s) have been used for comparison. Our results show that the mitochondrial haplotype of the commercial breeds has spread throughout the territory, which, together with subtle changes observed in the nuclear genetic diversity of the populations, indicates that hybridization and consequent introgression are occurring in most of the peninsula. It is, therefore, necessary to improve the existing legislation concerning the management and exportation of commercial bumblebees to conserve locally adapted populations.

Flower strips enhance abundance of bumble bee queens and males in landscapes with few honey bee hives

Wild bee declines in agricultural landscapes have led farmers to supplement crops with honey bees. Simultaneously, environmental subsidy and conservation programmes have incentivized farmers to establish flower strips to support wild and managed pollinators. To find out if flower strips enhance, and competition from honey bees suppresses, wild bees in the landscape and across seasons, we surveyed bumble bee and honey bee abundances in 16 sites in Sweden in summer 2018. The centre of each site (2 km radius) was with or without an annual flower strip, and with or without added honey bee hives. We surveyed bees in each flower strip and in linear habitats in the landscape around each site, such as field edges and road verges. In the following spring, we surveyed bumble bee queen abundance in each site. We show that adding flower strips benefits bumble bee queen abundance the following year, but this effect is diminished if honeybee hives are added. In sites with flower strips, added honey bee hives reduced male bumble bee abundance. Our relatively small flower strip areas bolstered bumble bee population growth across seasons, probably by relieving a resource bottleneck. Adding honey bee hives in combination with flower strips to landscapes with few floral resources should be avoided as it cancelled the positive effect of flower strips.

Field boundary features can stabilise bee populations and the pollination of mass‐flowering crops in rotational systems

Abstract Pollinators experience large spatiotemporal fluctuations in resource availability when mass‐flowering crops are rotated with resource‐poor cereal crops. Yet, few studies have considered the effect this has on pollinator population stability, nor how this might be mitigated to maintain consistent crop pollination services. We assess the potential of boundary features (standard narrow 1 m grassy margins, hedgerows and wide 4 m agri‐environment margins) to support and stabilise pollinator populations and pollination service in agricultural landscapes under crop rotation. Assuming a 6‐year rotation, we use a process‐based pollinator model to predict yearly pollinator population size and in‐crop visitation rates to oilseed rape and field bean across 117 study landscapes in England with varying amounts of boundary features. We model both ground‐nesting bumblebees and solitary bees and compare the predictions including and excluding boundary features from the landscapes. Ground‐nesting bumblebee populations, whose longer‐lifetime colonies benefit from continuity of resources, were larger and more stable (relative to the no‐features scenario) in landscapes with more boundary features. Ground‐nesting solitary bee populations were also larger but not significantly more stable, except with the introduction of wide permanent agri‐environment margins, due to their shorter lifetimes and shorter foraging/dispersal ranges. Crop visitation by ground‐nesting bumblebees was greater and more stable in landscapes with more boundary features, partly due to increased colony growth prior to crop flowering. Time averaged crop visitation by ground‐nesting solitary bees was slightly lower, due to females dividing their foraging time between boundary features and the crop. However, despite this, the minimum pollination service delivered was higher, due to the more stable delivery. Synthesis and applications. Field boundary features have an important role in stabilising pollinator populations and pollination service in rotational systems, although maintenance of larger semi‐natural habitat patches may be more effective for stabilising less mobile solitary bee populations. We recommend using combinations of boundary features, accounting for pollinator range when spacing features/rotating crops, and synchronising boundary feature management with crop rotation to maximise their stabilising benefits.

Characterizing the Mitogenome of the Endemic Bumblebee Subspecies from the Canary Islands for Conservation Purposes

The taxonomic status of Bombus terrestris subspecies is complex and has deep implications in the management of commercial bumblebees for crop pollination as well as in the establishment of appropriate conservation plans. Herein, the complete mitogenome of the endemic Canary Islands subspecies Bombus terrestris canariensis is newly sequenced and compared with available mitochondrial sequences in order to shed light into its taxonomic status. The mitochondrial genome was 17,300 bp in length and contained 37 genes, including 13 protein-coding genes (PCGs), two rRNAs, and 22 tRNAs and a partial sequence of the AT rich control region. The phylogenetic analysis of PCGs of the mitogenome was congruent with its subspecific status and a close relationship with the North African subspecies africanus as previously suggested. The sequencing of the mitogenome of B. t. canariensis provides useful genetic information to study the conservation genetics and genetic diversity of these island bumblebee populations.

BEE‐STEWARD: A research and decision‐support software for effective land management to promote bumblebee populations

Abstract The demand for agent‐based models to explore the effects of environmental change on pollinator population dynamics is growing. However, models need a simple yet flexible interface to enable adoption by a wide range of stakeholders. We introduce BEE‐STEWARD: a research and decision‐support software tool, enabling researchers, policymakers, land management advisors and practitioners to predict and compare the effects of bee‐friendly management interventions on bumblebee populations over several years. BEE‐STEWARD integrates the BEESCOUT and Bumble‐BEEHAVE agent‐based models of bumblebee behaviour, colony growth and landscape exploration into a user‐friendly interface, with reconstructed code, and expanded functionality. Bespoke automatic reports can be created to illustrate how different land management interventions can affect the densities of bumblebees and their colonies over time. BEE‐STEWARD could be an important virtual test bed for scientists exploring the impacts of different stressors on bumblebees and used by those with little or no modelling experience, enabling a shared methodology between research, policy and practice.

A molecular genetic method for estimating nest density in bumblebee populations without explicit definition of habitat area

A molecular genetic method for estimating nest density in bumblebee populations without explicit definition of habitat area

The potential for parasite spill-back from commercial bumblebee colonies: a neglected threat to wild bees?

Commercially-reared bumblebee colonies provide pollination services to numerous crop species globally. These colonies may harbour parasites which can spill-over to wild bee species. However, the potential for parasites to spread from wild to commercial bumblebees, which could then lead to parasite spill-back, is poorly understood. To investigate this, parasite-free commercial Bombus terrestris audax colonies, which are used commercially for strawberry pollination, were placed into seasonal strawberry crops for either 6- or 8-week blocks across two key time periods, early spring and early summer. Bumblebees were removed from colonies weekly and screened for the presence of parasites. In the early spring placement, only one parasite, the highly virulent neogregarine Apicystis bombi, was detected at a low prevalence (0.46% across all bees screened). In contrast, all colonies placed in the crop in the early summer became infected. A trypanosome, Crithidia bombi, and A. bombi were the most prevalent parasites across all samples, reaching peak prevalence in screened bees of 39.39% and 18.18% respectively at the end of the experimental period. The prevalence of A. bombi was greater than most UK records from wild bumblebees, suggesting that commercial colonies could enhance levels of A. bombi infection in wild bees through spill-back. Studies on larger geographical scales with different commercial colony densities are required to fully assess spill-back risk. However, seasonal management, to minimise spill-back opportunities, and treatment of commercial colonies to prevent infection, could be implemented to manage the potential risks of parasite spill-back to wild bees.Implications for insect conservation Our results show that commercial bumblebee populations do pick up infections, most likely from wild bees, and that these infections can reach prevalences where they may pose a threat to wild bees via parasite spill-back. More research is required to clarify the extent of this potential threat.

An Evaluation of Habitat Uses and Their Implications for the Conservation of the Chinese Bumblebee Bombus pyrosoma (Hymenoptera: Apidae)

Bumblebees are important pollinators for many wild plants and crops. However, the bumblebee populations are seriously declining in many parts of the world. Hence, the bumblebee conservation strategy should be urgently addressed, and the species distribution modeling approach can effectively evaluate the potentially suitable areas for their conservation. Here, one of the most abundant and endemic species of bumblebee in China, Bombus pyrosoma, was selected to assess current and future climates’ influence on its distribution with MaxEnt. Nine high-resolution bioclimatic/environmental variables with high contribution rates and low correlations were used. Four of the nine bioclimatic/environmental variables, min temperature of the coldest month (bio_06), annual mean temperature (bio_01), precipitation of wettest month (bio_13) and radiation of warmest quarter (bio_26), were found to be the most critical factors influencing the distribution of B. pyrosoma. The modeling results showed that the areas with high and moderate suitability for B. pyrosoma covered 141,858 and 186,198 km2 under the current climate conditions. More than 85% of the sampling sites in 2019 were found to be suitable under the current scenario. Under the future A1B and A2 scenarios in 2050 and 2100, the areas with low and moderate suitability for B. pyrosoma increased. However, alarmingly, the high suitability areas decreased under the future A1B and A2 scenarios in 2050 and 2100. Furthermore, regions covering seven provinces of northern China were the most crucial for developing nature reserves for B. pyrosoma, with the following order of suitable areas: Gansu, Shanxi, Ningxia, Qinghai, Shaanxi, Hebei and Beijing. Our study highlights the impact of future climate changes on the distribution of B. pyrosoma, and conservation strategies should mitigate the threats posed by environmental changes, particularly in the current high suitability areas.

Eusocial insect declines: Insecticide impairs sperm and feeding glands in bumblebees

Insecticides are contributing to global insect declines, thereby creating demand to understand the mechanisms underlying reduced fitness. In the eusocial Hymenoptera, inclusive fitness depends on successful mating of male sexuals (drones) and efficient collaborative brood care by female workers. Therefore, sublethal insecticide effects on sperm and glands used in larval feeding (hypopharyngeal glands (HPG)) would provide key mechanisms for population declines in eusocial insects. However, while negative impacts for bumblebee colony fitness have been documented, the effects of insecticide exposure on individual physiology are less well understood. Here, we show that field-realistic concentrations (4.5–40 ng ml−1) of the neonicotinoid insecticide thiamethoxam significantly impair Bombus terrestris sperm and HPGs, thereby providing plausible mechanisms underlying bumblebee population decline. In the laboratory, drones and workers were exposed to five thiamethoxam concentrations (4.5 to 1000 ng ml−1). Then, survival, food consumption, body mass, HPG development, sperm quantity and viability were assessed. At all concentrations, drones were more exposed than workers due to higher food consumption. Increased body mass was observed in drones starting at 20 ng ml−1 and in workers at 100 ng ml−1. Furthermore, environmentally realistic concentrations (4.5–40 ng ml−1) did not significantly affect survival or consumption for either sex. However, thiamethoxam exposure significantly negatively affected both sperm viability and HPG development at all tested concentrations. Therefore, the results indicate a trade-off between survival and fitness components, possibly due to costly detoxification. Since sperm and HPG are corner stones of colony fitness, the data offer plausible mechanisms for bumblebee population declines. To adequately mitigate ongoing biodiversity declines for the eusocial insects, this study suggests it is essential to evaluate the impact of insecticides on fitness parameters of both sexuals and workers.

Organic winter cereals benefit bumblebee colonies in agricultural landscapes with mass‐flowering crops

Abstract Scant floral resources are a major cause of declining pollinator populations in farmland. Measures to increase floral resources on arable land include agronomically non‐productive approaches, like flowering fields (seed mixture of flowering forbs sown on fallows) and production‐integrated approaches like organically farmed crops sustaining flowering arable wild plants. However, little is known about their relative efficacy for bumblebee conservation. We observed weight gain, foraging activity, worker body size, queen brood cell number and analysed stored pollen types of Bombus terrestris colonies experimentally sited adjacent to arable fields farmed under four crop‐use types: (i) cereal mono‐crops (winter wheat) under conventional farming, (ii) non‐productive conventional flowering fields, (iii) organic cereal mono‐crops (winter spelt) and (iv) organic legume mixed‐crops (lentil mixed‐crop). Additionally, we analysed the effects of flower cover in the surrounding landscape. Colonies located adjacent to organic winter spelt fields had higher foraging activity and larger body sizes, whereas other colony performance measures were unaffected by local crop‐use type. Phacelia tanacetifolia, which was only cultivated in flowering fields, accounted for about 50% of the total pollen amount irrespective of crop‐use type. This indicated a landscape‐wide attraction for B. terrestris to flowering fields. Flower cover in the surrounding landscape did not affect colony development, but negatively affected pollen diversity. We conclude that although the pollen supply of flowering fields in the surrounding landscape strongly attracts bumblebees, local bumblebee populations could still benefit from less intensive farming practices increasing flowering wild plant diversity, such as with flower‐rich organic winter cereals.

Study of the quality and safety of microbiological bioformulations for plant protection and growth stimulation

Bioformulations containing microorganisms that have various useful properties for plants are widely used as an alternative to chemical pesticides. Methods for evaluating the quality of such biological products have not yet been standardized. Composition of bioformulations used for protecting plants and stimulating plant growth was studied with molecular methods. Toxicity of bioformulations was evaluated on laboratory populations of bumblebees (Bombus terrestris L.). The number of bacteria in the two bioformulations was significantly less than the manufacturer’s stated. The declared composition of microorganisms in 33% of bioformulations did not fully or partially correspond to the identified composition. Klebsiella sp. and Citrobacter sp. bacteria were found among non-target bacteria. It is known that some species of these bacteria genera are opportunistic for humans. Not one of the studied bioformulations did not cause the death of bumblebees. However, it was found that 5 bioformulations out of 18 reduced the flight activity of bumblebees, which indicates their toxic effect. The data obtained by us shows that it is necessary to develop standardized methods for assessing the quality and safety of microbiological bioformulations that are available for public sale.

Bumblebee colony density on farmland is influenced by late‐summer nectar supply and garden cover

Abstract Floral resources are important in limiting pollinator populations, but they are often highly variable across time and space and the effect of this variation on pollinator population dynamics is not well understood. The phenology (timing) of floral resources is thought to be important in structuring pollinator populations, but few studies have directly investigated this. Our study quantifies the landscape composition, seasonal nectar and pollen supply and Bombus terrestris colony density of 12 farms in southwest UK to investigate how landscape composition influences the phenology of floral resources and how both these factors affect colony density. We use this information in a spatially explicit predictive model to estimate the effect of different farmland management scenarios on seasonal resource supplies and colony density. We find that farmland nectar supply during September is a strong predictor of B. terrestris colony density in the following year, explaining over half of all the variation in colony density; no other period of resource availability showed a significant association. Semi‐natural habitat cover was not a good proxy for nectar or pollen supply and showed no significant association with colony density. However, the proportional cover of gardens in the landscape was significantly associated with colony density. The predictive model results suggest that increasing the area of semi‐natural flowering habitat has limited effect on bumblebee populations. However, improving the quality of these habitats through Environmental Stewardship and other management options is predicted to reduce the late‐summer resource bottleneck and increase colony density. Synthesis and Applications. Our study demonstrates the importance of considering the phenology of resources, rather than just total resource availability, when designing measures to support pollinators. Late summer appears to be a resource bottleneck for bumblebees in UK farmland, and consequently management strategies which increase late‐summer nectar availability may be the most effective. These include mowing regimes to delay flowering of field margins until September, planting late‐flowering cover crops such as red clover and supporting late‐flowering wild plant species such as Hedera helix. Our results also suggest that rural gardens may play an important role in supporting farmland bumblebee populations.

Corridors through time: Does resource continuity impact pollinator communities, populations, and individuals?

Spatial aspects of connectivity have received considerable attention from ecologists and conservationists, yet temporal connectivity, the periodic linking of habitats, plays an equally important, but largely overlooked role. Different biological and biophysical attributes of ecosystems underpin temporal connectivity, but here we focus on resource continuity, the uninterrupted availability of foraging sites. We test the response of pollinators to resource continuity at community, population, and individual levels using a novel natural experiment consisting of farms with either single or sequential cropping systems. We found significant effects at the population level; colony density of an important crop pollinator (Bombus impatiens L.) was greater when crop floral resources were continuously available. However, we did not find significant effects at the community or individual level; wild bee abundance, diversity and body size did not respond to resource continuity. Raspberry farms with greater early season resources provided by blueberry had greater bumble bee populations, suggesting beneficial effects on resource availability due to crop diversity. Better understanding the impact of resource continuity via crop diversity on broader patterns of biodiversity is essential for the co-management of biodiversity and ecosystem services.

Diversity and Trophic Relationships of Functional Groups of Bumblebees (Hymenoptera: Apidae, Bombus Latreille, 1802) in Urban Habitats

Species composition, distribution, and trophic relationships of bumblebees are studied in six types of urban habitat: urban parks, botanical gardens, least-disturbed areas within the city, residential areas, and roadsides. Twenty bumblebee species are recorded in the present study. The species composition of bumblebees has changed from 1933 to 2017. Rare species have disappeared from the city—Bombus fragrans, B. cullumanus, and B. jonellus. The core of urban bumblebee communities consists of ecologically plastic species, most of which belong to the functional morphoecological “short-tongued” group (83%). The more specialized “medium-tongued” and “long-tongued” species are less diverse. Their populations make up 14% and 3% of the total bumblebee population. Five most common species, B. lucorum, B. terrestris, B. lapidarius, B. pascuorum, and B. hypnorum, are found at locations of the most noted categories of habitats. One of the main factors affecting the diversity of morphoecological groups of bumblebees in urban conditions is the state of floral resources. The bumblebees are observed feeding on more than 60 plant species of the families Asteraceae, Fabaceae, Lamiaceae, Rosaceae, and Salicaceae in urban environment; however, the insects favored plants of 30 species. The ornamental, ruderal, and some invasive species of plants are significant in bumblebees’ feeding in urban conditions. The resources for bumblebee feeding and sustainable density of nesting sites are rich in quality and quantity only at a few of model urban sites. At these territories, the highest species diversity of bumblebee is recorded, including rare, protected, and vulnerable species. The ecological potential of other studied urban sites is enough to sustain the most ecologically plastic bumblebee species.

Annual flowers strips benefit bumble bee colony growth and reproduction

Bumble bees are important crop pollinators but are negatively impacted by agricultural intensification and concomitant loss of floral resources. Flower strips can increase the abundance and sometimes the diversity of bumble bees at local scales, but the importance of flower strips for bumble bee populations at larger scales remains poorly understood. We investigated the effect of flower strips on bumble bee colony growth and reproduction at landscape scales. Commercial bumble bee colonies of a native species (Bombus terrestris) were placed and monitored at different distances from flower strips that were sown on existing ecological focus areas (European Common Agricultural Policy) in southern Sweden. Both the average colony growth (weight) and the production of reproductives (drones and queens) were highest for colonies adjacent to flower strips and declined with increasing distance. Colonies close to the flower strip also produced more reproductives per colony weight. Colony foraging activity was negatively related to the distance to flower strips whereas worker size was not affected. Annual flower strips in ecological focus areas benefit bumble bee colonies by increasing foraging success, colony growth and finally boosting sexual reproduction, demonstrating potential benefits for pollination within and between seasons. These effects were spatially limited but extended to foraging ranges of bumble bees. However, effects of increased colony growth on the abundance of foraging bees in the landscape may extend to larger distances because of forager movements within seasons and queen dispersal between seasons, suggesting that voluntary or incentivised collaboration between farmers may be needed to achieve optimal implementation of flower strips.

Native and agricultural grassland use by stable and declining bumble bees in Midwestern North America

Abstract Bumble bees are important pollinators in both natural and anthropogenic systems. In recent years, some species have suffered declines, including in the American Midwest. While loss of floral resources and grassland habitat may contribute to these declines, little is known about how native versus agricultural grasslands affect bumble bee populations. We conducted 3 years of bumble bee population and floral use surveys across restored tallgrass prairie, bison pasture, and cattle pasture in Northern Illinois. We found 1.75–3.5 times more bumble bees in native plant dominant tallgrass prairie than in exotic‐dominant pasture sites. In addition, bumble bees were two times more abundant in bison pasture than in cattle pasture. Bumble bee species richness was approximately 1.5–2 times greater in prairie, while richness was comparable in the two pasture sites. Habitat‐dependent abundance and richness were driven by individual bumble bee species habitat preferences. Across habitats, native Monarda fistulosa was highly favoured by foraging bumble bees, particularly by the regionally declining B. auricomus. In the absence of native species, exotic Trifolium pratense and Daucus carota were important forage sources in pastures. These results indicate that grassland management practises to shift grassland plant communities towards native‐dominant over exotic‐dominant communities may strengthen bumble bee populations, although these effects will likely be Bombus species‐dependent. Our findings highlight the need to understand the impacts of habitat on specific bumble bee species, as this will be critical in developing conservation plans for declining populations now and in the future.

The Importance of Males to Bumble Bee (Bombus Species) Nest Development and Colony Viability.

Simple SummaryPopulations of some bumble bee species have declined over the last decade. Recognizing the importance of bumble bees to agriculture and natural ecosystems, there has been an upwelling of research to better understand the underlying reasons for observed population declines. While most research has addressed the health of bumble bee females (i.e., workers and queens), males have been largely ignored. Here, we explore the available published literature on the role males play in improving queen health and reproductive fitness, as well as in overall nest success. We conclude that males serve a unique and important role in bumble bee colony success.Bumble bee population declines over the last decade have stimulated strong interest in determining causative factors and necessary conservation measures. Research attention has largely been directed toward bumble bee worker and queen health and their contributions to population stability, while male bees (i.e., drones) have typically been overlooked regarding their role in influencing colony fitness and longevity. In this review we assess existing literature on the diverse role of males within bumble bee nests and their importance to queen health and fitness, as well as to overall nest success. The implications of reproductive measures, including sperm transfer, mating behavior, mating plugs, and male immunity, among other topics, are examined. Overall, bumble bee males are found to drive colony function in a unique manner. Current knowledge gaps pertaining to the role of males are discussed. We highlight the importance of drones to queen success and fitness in many ways, and suggest future research exploring impacts of this often-neglected caste.

Past, present and future distributions of bumblebees in South America: Identifying priority species and areas for conservation

Abstract Climate change has been commonly associated with a decline of bumblebee populations around the world. However, most information regarding the impacts of climate change on bumblebees is derived from North America and Europe, and little is known about South American species. Here we applied ecological niche modelling techniques to estimate the past, present and future distributions of six Bombus species found in South America. These data were used to estimate climatically stable areas (CSAs) for each species and, combined with information on land cover and protected area network, identify species and areas for the conservation of these important pollinators. The models predicted a reduction in climatically suitable habitats from Last Glacial Maximum (LGM) to the present for most species. Similarly, all species were predicted to lose climatically suitable areas in future climate scenarios, ranging from 9% to 78%, depending on the species and climate change scenario. The percentage of legally protected CSAs varied between 4.0% and 48.2% among species, mainly due to differences in the protected area network among the biomes in which they occur. A significant portion of the distribution range of most species includes agricultural areas, which likely increases bumblebee exposure to pesticides. Based on the estimated habitat loss due to climate change, as well as from land cover and protected area, our results indicate that Bombus bellicosus, Bombus brevivillus and Bombus brasiliensis are the most endangered species of those evaluated. Synthesis and applications. Our findings provide a framework for conservation strategies of six species of South American bumblebees, by prioritizing species and areas for conservation considering their distribution range and the climatically stable areas under different climate change scenarios.