Bombus Research Articles

Evaluation of the most popular annual flowers sold in the United States and Europe indicates low visitation rates by pollinators and large variation among cultivars.

To better understand how frequently pollinators visit the most popular annuals and the variation among cultivars, we evaluated 3-6 cultivars, each of petunia, impatiens, begonia, geranium, pansy, and New Guinea impatiens. These 6 annuals account for 46.6% of all garden center annual flower sales in the United States. Flower visits by honey bees, bumble bees, syrphids, other Diptera and other Hymenoptera, combined, varied 3 to 10-fold among cultivars within each of the 6 popular annuals. Begonia and impatiens were visited more frequently by pollinators than pansy, petunia, NG impatiens, and geranium. The 4 most visited cultivars, begonia 'Cocktail Brandy', begonia 'Ambassador Rose Blush', impatiens 'Accent Coral', and impatiens 'Super Elfin XP White' attracted as many pollinators as a benchmark annual, marigold 'Alumia Vanilla Cream', considered as moderately attractive to pollinators. Some conclusions from this research may be helpful for homeowners, landscapers, growers, and breeders. First, the most popular annual flowers are not a good choice for the purpose of attracting and supporting pollinators. However, the large variation among cultivars provides an opportunity to select cultivars that are more attractive to pollinators, particularly for begonia and impatiens. If the most pollinator-visited cultivars of begonia and impatiens are labeled and promoted as such, it would be beneficial to pollinators in urban and suburban landscapes in the USA and Europe, where they comprise 10%-20% of all annual flowers purchased from garden centers.

Temperature influences desiccation resistance of bumble bees

Ongoing climate change has increased temperatures and the frequency of droughts in many parts of the world, potentially intensifying the desiccation risk for insects. Because resisting desiccation becomes more difficult at higher temperatures and lower humidity, avoiding water loss is a key challenge facing terrestrial insects. However, few studies have examined the interactive effects of temperature and environmental humidity on desiccation resistance in insects. Such studies on bees (Hymenoptera: Apoidea: Anthophila) are especially rare, despite their ecological and economic importance. Here, we crossed temperature (20, 25, and 30 °C) with humidity (<5, 50, >95 % RH) manipulations and measured time to mortality, water loss rates, and the water content at mortality of bumble bees (Bombus impatiens). We found that both higher temperature and lower humidity increased water loss rates, while warmer temperatures reduced survival time and lower humidity decreased water content at mortality. Additionally, we observed large intraspecific variation in water balance traits between colonies, and larger individuals survived longer and could tolerate more water loss before mortality. This study raises important questions about the mechanisms underpinning water loss in bumble bees and suggests that frequent access to nectar may be especially important for bumble bees’ water balance and survival in a warming and drying climate.

Leveraging virtual datasets to investigate the interplay of pollinators, protected areas, and SDG 15

Biodiversity loss amplifies the need for taxonomic understanding at global, regional, and local scales. The United Nations Environmental Programme Sustainable Development Goals are explicit in their demand for greater accountability with respect to ecosystem management, and Sustainable Development Goal 15, Life on Land, specifically calls for a halt to biodiversity loss. Pollinators (bees and butterflies) are two functional groups with public attention for protection, yet little long-term data availability. National Parks, including those in the United States, act as optimal sites to study biodiversity loss, but historic data tends to vary in availability. This study addresses systematic taxonomic and digitalization biases present within historic (museum), modern (citizen science), and non-digitized (private collection) datasets for Yellowstone and Grand Teton National Parks from 1900 to 2021. We find that, although database record availability is representative of butterfly and bumble bee groups known for the area, categories such as data rescue, digitalization/availability, and management/archiving vary across database types. These findings on virtual datasets offer opportunities for conservationists to understand the efficacy of digitized collections in addressing questions of species loss over time, including the strengths and pitfalls of digitized data repositories. Additionally, virtual datasets can be utilized to monitor biodiversity under Sustainable Development Goal 15 targets while also promoting broader access to resources such as museum collections for educational purposes.

A rapid return to normal: temporal gene expression patterns following cold exposure in the bumble bee Bombus impatiens.

Bumble bees are common in cooler climates and many species likely experience periodic exposure to very cold temperatures, but little is known about the temporal dynamics of cold response mechanisms following chill exposure, especially how persistent effects of cold exposure may facilitate tolerance of future events. To investigate molecular processes involved in the temporal response by bumble bees to acute cold exposure, we compared mRNA transcript abundance in Bombus impatiens workers exposed to 0°C for 75 min (inducing chill coma) and control bees maintained at a constant ambient temperature (28°C). We sequenced the 3' end of mRNA transcripts (TagSeq) to quantify gene expression in thoracic tissue of bees at several time points (0, 10, 30, 120 and 720 min) following cold exposure. Significant differences from control bees were only detectable within 30 min after the treatment, with most occurring at the 10min recovery time point. Genes associated with gluconeogenesis and glycolysis were most notably upregulated, while genes related to lipid and purine metabolism were downregulated. The observed patterns of expression indicate a rapid recovery after chill coma, suggesting an acute differential transcriptional response during recovery from chill coma and return to baseline expression levels within an hour, with no long-term gene expression markers of this cold exposure. Our work highlights the functions and pathways important for acute cold recovery, provides an estimated time frame for recovery from cold exposure in bumble bees, and suggests that cold hardening may be less important for these heterothermic insects.

ECR Spotlight – Kelton Verble and Ellen Keaveny

ECR Spotlight is a series of interviews with early-career authors from a selection of papers published in Journal of Experimental Biology and aims to promote not only the diversity of early-career researchers (ECRs) working in experimental biology but also the huge variety of animals and physiological systems that are essential for the ‘comparative’ approach. Kelton Verble and Ellen Keaveny are authors on ‘A rapid return to normal: temporal gene expression patterns following cold exposure in the bumble bee Bombus impatiens’, published in JEB. Kelton is a PhD candidate in the lab of Dr Jeffrey Lozier at The University of Alabama, USA, investigating the transcriptomics and epigenomics underlying thermal tolerance in bumble bees. Ellen is a PhD candidate in the lab of Michael Dillon at the University of Wyoming, USA, investigating how temperature affects bumble bees at cellular, organismal, population and community levels.

Patterns of virus coincidence between honey bees and bumble bees in the Pacific Northwest, USA

Patterns of virus coincidence between honey bees and bumble bees in the Pacific Northwest, USA

Impacts of Asteraceae pollen spines on bumble bee survival and larval growth

Impacts of Asteraceae pollen spines on bumble bee survival and larval growth

Intercropping Industrial Hemp and Cowpea Enhances the Yield of Squash—A Pollinator-Dependent Crop

Cultural crop-production practices are not only engineered to minimize pest incidence but also improve resource use efficiency and increase the diversity of habitat for beneficial insects that provide pollination services. With the increasing cultivation of industrial hemp and the benefits associated with the cultivation of multiple crops, its integration into a polyculture cropping system remains to be evaluated. We intercropped two pollinator-attractive crops, hemp and cowpea, with squash, a pollinator-dependent crop, to evaluate the impact of pollinator abundance and diversity on crop yield. Intercropping significantly increased the overall abundance of pollinators with 79.1% recorded from the intercropping systems compared to 21.9% in the monocropping systems. Sweat bees and bumble bees were the most abundant bees, and Squash+Cowpea was the most diverse cropping system. Intercropping significantly increased the yield of squash with higher squash yield (155%) in Hemp+Squash and (161%) in Squash+Cowpea than in squash monocrop. Also, intercropping resulted in higher hemp yield (64%) in Hemp+Cowpea and (165%) in Hemp+Squash compared to hemp monocrop. This study demonstrated that agricultural systems such as intercropping that are designed to attract pollinators are much more productive by not only improving crop yield but also growers’ returns on investments.

Parasitoid flies associated with bumble bees (Bombus spp.) in Argentina

Parasitoid flies associated with bumble bees (Bombus spp.) in Argentina

Occurrence of black queen cell virus in wild bumble bee communities in China

Occurrence of black queen cell virus in wild bumble bee communities in China

Do diesel exhaust particles in pollen affect colony founding in the bumble bee Bombus terrestris?

Do diesel exhaust particles in pollen affect colony founding in the bumble bee Bombus terrestris?

A new bot fly species of Cuterebra (Diptera: Oestridae) from Ecuador

A new species of cuterebrine rodent bot fly, Cuterebra yanayacui sp. nov., is described from the cloud forest of Ecuador, and it is argued that the species mimics a range of aculeate hymenopterans, including euglossine orchid bees of the genera Eufriesea Cockerell and Eulaema Lepeletier and bumble bees of the subgenus Cullumanobombus Vogt. Montemyia bureni Dalmat, 1942 is proposed as a junior synonym of Cuterebra ornata Bau, 1928, syn. nov., and an updated identification key to the species of the Metacuterebra species group within Cuterebra Clark is provided. The 5’-end of the Cytochrome c oxidase subunit I gene is sequenced for the new species and compared with published Cuterebra sequences.

Metabolic Rate Suppression and Maintenance of Flight Muscle Metabolic Capacity during Diapause in Bumble Bee (Bombus impatiens) Queens

Metabolic Rate Suppression and Maintenance of Flight Muscle Metabolic Capacity during Diapause in Bumble Bee (<i>Bombus impatiens</i>) Queens

Apivectoring: Harnessing pollinators for sustainable crop protection and pollination

Apivectoring, or Pollinator Biocontrol Vector Technology, employs bees to distribute biological control agents, offering a sustainable solution for managing plant diseases and insect pests while enhancing crop yield and quality. The most commonly used vectors in apivectoring are honey bees and bumble bees, though there’s potential to explore other pollinator species. Commercial dispensers like BeeTreat Dispenser®, BVT Inoculum Dispenser® and Flying Doctors® have been developed in countries like Finland, Belgium, and Canada, respectively. Though initially pioneered in North America, Australia, and Europe, this method is now being evaluated in India. The technology is a promising alternative to chemical pest control, reducing pesticide usage and ensuring crop pollination, although challenges remain in regions deprived of local rearing and/or research facilities.

Debunking wasp pollination: Wasps are comparable to bees in terms of plant interactions, body pollen and single‐visit pollen deposition

Abstract Wasps are understudied in their contribution to pollination services. In order to better understand the ecological contribution of wasp communities to plant pollination, we conducted three studies to compare bees and wasps by (1) the plant communities visited in agricultural and prairie environments, (2) body pollen composition as an indirect measure of pollination and (3) a single‐visit deposition study as a direct measure of pollination in the plant species complex Solidago canadensis. We found wasps visit a distinct early‐blooming exotic plant community from bees but have overlapping use of late‐blooming native plants and similar network interaction metrics. This suggests wasps may fill an ecological niche distinct from bees, while also serving as common native plant visitors. We also found that body pollen density and pollen fidelity in four and five (out of six) wasp families, respectively, were comparable to or greater than the bee family Colletidae. Three wasp families also showed comparable to or greater visit fidelity than two (out of five) bee families examined. These results suggest wasps may carry and potentially deliver substantial pollen to specific plants. In addition, controlled single‐visit deposition revealed the paper wasp Polistes fuscatus deposits a similar amount of pollen grains as the bumble bee Bombus impatiens, suggesting surprisingly high pollination efficiency that warrants further investigation. Our multi‐pronged study shows the importance of investigating the role of wasps as pollinators, especially by focusing on direct plant‐pollination metrics to determine wasp pollination efficacy.

Insight on kleptoparasitic bee, Melecta chinensis (hymenoptera: Apidae), in the Republic of Korea: Morphology, biology and molecular characteristics

AbstractThis study focused on a kleptoparasitic bee, Melecta chinensis, which is not well‐known in the Republic of Korea. We provided a detailed morphological illustration of the adult bees and their nesting biological characteristics with distributional data. Additionally, the complete mitochondrial genome of the species is presented for the first time, and its phylogenetic position within the family Apidae is estimated.As a result, we could suggest a full redescription of M. chinenesis for identification and a newly reported potential flower host for it. In addition, the mitochondrial DNA (mtDNA) of M. chinensis is revealed as 15,489 base pairs (bp) long, with 35 eukaryotic mitochondrial genes (13PCGs, 2 rRNAs, and 20 tRNAs) and a 706 bp AT‐rich region. The overall base composition is 75.82% AT and 24.18% GC. The 13 protein‐coding genes (PCGs) started with a typical ATN codon (ATA in nine genes and ATG in four genes) and terminated with TNN (TAN in 10 genes and TTT in one gene) or ANN (AAC in one gene and ATT in one gene). The phylogenetic results based on 13 PCGs showed that M. chinensis is distantly positioned to bumble bees (Bombus) and honey bees (Apis) but closely related to a stingless bee, Frieseomelitta varia, within the family.

Niche analyses and the potential distribution of four invasive bumblebees worldwide.

The introduction of bees for agricultural production in distinct parts of the world and poor management have led to invasion processes that affect biodiversity, significantly impacting native species. Different Bombus species with invasive potential have been recorded spreading in different regions worldwide, generating ecological and economic losses. We applied environmental niche and potential distribution analyses to four species of the genus Bombus to evaluate the similarities and differences between their native and invaded ranges. We found that B. impatiens has an extended environmental niche, going from dry environmental conditions in the native range to warmer and wetter conditions in the invaded range. Bombus ruderatus also exhibited an extended environmental niche with drier and warmer conditions in the invaded range than in its native range. Bombus subterraneus expanded its environmental niche from cooler and wetter conditions in the native range to drier and warmer conditions in the invaded range. Finally, B. terrestris showed the most significant variation in the environmental niche, extending to areas with similar and different environmental conditions from its native range. The distribution models agreed with the known distributions for the four Bombus species, presenting geographic areas known to be occupied by each species in different regions worldwide. The niche analysis indicate shifts in the niches from the native to the invaded distribution area of the bee species. Still, niche similarities were observed in the areas of greatest suitability in the potential distribution for B. ruderatus, B. subterraneus, and B. terrestris, and to a lesser degree in the same areas with B. impatiens. These species require similar environmental conditions as in their native ranges to be established in their introduced ranges. Still, they can adapt to changes in temperature and humidity, allowing them to expand their ranges into new climatic conditions.

Diversity of bumble bees and butterflies in Minnesota roadsides depends on floral diversity and abundance but not floral native status

Abstract Habitat loss is an important driver in the rapid decline of many insects. The restoration of roadside habitat has been touted as an opportunity to support communities of bumble bees and butterflies, two insect groups of conservation concern. However, it is unclear how current roadside restoration methods translate to pollinator abundance and diversity. Here, we ask how the plant communities of roadsides seeded with native and non‐native seed mixes affect bumble bee and butterfly communities 2–20 years after planting. We found that bumble bee and butterfly abundance and diversity were positively correlated with floral abundance and diversity. However, the pollinator community in plots planted with diverse native seed mixes did not differ from that found in plots seeded with species‐poor non‐native mixes, likely because many forbs in the native seed mixes had poor establishment, and all plots were readily colonised by species that were never planted. While plots with more native flowers did not necessarily support higher pollinator diversity, we did find several native plants that established well in roadsides and supported pollinators, including goldenrods (Solidago spp.), milkweeds (Asclepias spp.) and wild bergamot (Monarda fistulosa). Our data suggest that managing a more diverse and abundant floral community will benefit bumble bees and butterflies. Refining the composition of native seed mixes, adding more floral abundance to non‐native mixes and investing in management for native plant communities may increase the habitat value of roadsides for pollinator communities.

A comparative genomic analysis of Fructobacillus evanidus sp. nov. from bumble bees

The increase in studies on bee microbiomes is prompted by concerns over global pollinator declines. Bumble bees host core and non-core microbiota which may contribute to increased lifetime fitness. The presence of Fructobacillus in the gut microbiomes of bumble bee workers, or the replacement of core symbionts with Fructobacillus bacteria, has been considered a marker of dysbiosis. A phylogenomic analysis and functional genomic characterization of the genomes of 21 Fructobacillus isolates from bumble bees demonstrated that they represented four species, i.e. Fructobacillus cardui, Fructobacillus fructosus, Fructobacillus tropaeoli, and the novel species Fructobacillus evanidus sp. nov. Our results confirmed and substantiated the presence of two phylogenetically and functionally distinct Fructobacillus species clades that differ in genome size, percentage G + C content, the number of coding DNA sequences and metabolic characteristics. Clade 1 and clade 2 species differed in amino acid and, to a lesser extent, in carbohydrate metabolism, with F. evanidus and F. tropaeoli genomes featuring a higher number of complete metabolic pathways. While Fructobacillus genomes encoded genes that allow adhesion, biofilm formation, antibacterial activity and detoxification, other bacteria isolated from the bumble bee gut appeared better equipped to co-exist with the bumble bee host. The isolation and identification of multiple Fructobacillus species from several bumble bee gut samples in the present study also argued against a specific partnership between Fructobacillus species and their bumble bee hosts.

Bee Vectoring Technology Using Clonostachys rosea as a Biological Control for Botrytis Fruit Rot of Strawberry in Florida

Botrytis fruit rot (BFR), caused by Botrytis cinerea, is a major strawberry disease. The intensive use of fungicides for its management has resulted in resistance to several fungicide groups, requiring alternatives to BFR management. In this study, we evaluated the efficacy of bee vectoring technology (BVT) using Clonostachys rosea as a fungal biological control agent for BFR. BVT involves the use of bumble bees to carry C. rosea to strawberry flowers, where it can compete with B. cinerea. Three experiments were conducted on commercial farms in Florida during the 2016–17, 2017–18, and 2018–19 strawberry seasons. Treatments consisted of a nontreated control, fungicide standard program, BVT, and BVT + fungicide program. Fruits were harvested twice a week throughout the season to determine BFR incidence and yield, and postharvest activity was quantified during selected harvests. Temperature effect on mycelial growth was also determined for B. cinerea and C. rosea. The BVT + fungicide program reduced BFR incidence compared with the nontreated control in all seasons. However, BVT treatment by itself was not effective in improving yields or reducing disease incidence, likely due to highly favorable weather conditions for BFR in Florida. In addition, the low attractiveness of strawberry flowers to bumble bees and the fact that C. rosea is a better colonizer of strawberry leaves than flowers could also be limiting the effectiveness of BVT. Therefore, the BVT may be used in combination with fungicides to reduce BFR in strawberry production in Florida, but its cost-effectiveness still needs to be determined.