Genus-Wide Characterization of Nuclear Mitochondrial DNAs in Bumblebee (Hymenoptera: Apidae) Genomes

In eukaryotes, DNA of mitochondria is transferred into the nucleus and forms nuclear mitochondrial DNAs (NUMTs). Taking advantage of the abundant genomic resources for bumblebees, in this study, we de novo generated mitochondrial genomes (mitogenomes) for 11 bumblebee species. Then, we identified and characterized NUMTs in genus-wide bumblebee species. The number of identified NUMTs varies across those species, with numbers ranging from 32 to 72, and nuclear genome size is not positively related to NUMT number. The insertion sites of NUMTs in the nuclear genome are not random, with AT-rich regions harboring more NUMTs. In addition, our results suggest that NUMTs derived from the mitochondrial COX1 gene are most abundant in the bumblebee nuclear genome. Although the majority of NUMTs are found within intergenic regions, some NUMTs do reside within genic regions. Transcripts that contain both the NUMT sequence and its flanking non-NUMT sequences could be found in the bumblebee transcriptome, suggesting a potential domestication of NUMTs in the bumblebee. Taken together, our results shed light on the molecular features of NUMTs in the bumblebee and uncover their contribution to genome innovation.

Catching the thief: Nectar robbing behaviour by bumblebees on naturalised Fuchsia magellanica in Ireland

Fuchsia magellanica (Ongaraceae) is a plant with a traditionally ornithopholous pollination system, pollinated primarily by hummingbirds in its native range. As a naturalised alien plant in Ireland, F. magellanica is visited largely by bumblebees, with evidence for nectar robbing behaviour of the long-tubed flowers. We aimed to investigate nectar robbing behaviour of bumblebees on F. magellanica, and in particular whether floral and pollinator traits (size) determined likelihood of nectar robbing. While F. magellanica was visited by a number of bumblebee species, only two with shorter tongue lengths were observed to rob nectar from flowers. Although there was no observed relationship between intra-specific bee body size and nectar robbing behaviour, nectar robbing was observed most frequently in the site with the highest number of bees. Proportions of robbed flowers were low overall and varied between populations, but there was a significant relationship between flower size and whether it was nectar robbed with larger flowers robbed more often. Our work suggests that floral size determines whether a flower-visitor will choose to nectar rob or not in this system. Nectar robbing may also be related to bee density which could suggest this behaviour is driven by competition for resources, or that it is learnt by observing other bees.

Bombus (Megabombus) consobrinus Dahlbom, 1832 in the European North of Russia: its distribution and foraging preference

The focus of this study is to summarize the data on the distribution and foraging preference of Bombus (Megabombus) consobrinus Dahlbom, 1832 in the European North of Russia. The range of B. consobrinus in this region mostly repeats the disjunctions of the range of Aconitum septentrionale that is also known in Scandinavia. In other regions of Northern Eurasia, the close relationship of B. consobrinus with Aconitum is not obvious. This bumblebee species may be regarded as oligolectic in Northern Europe and the European North of Russia. We assume the presence of a coadaptive relationship of this bumblebee species with A. septentrionale in this region that presumably have been caused by the complex history of B. consobrinus in the European North.

Is Bombus pomorum (Panzer, 1805) (Hymenoptera: Apidae) a new bumblebee for Siberia or an indigenous species?

Bombus pomorum (Panzer, 1805) is known from Europe, Anatolia, the Caucasus, and to the Urals in Russia. Two specimens have been collected in the south of western Siberia for the first time. It is possible that the species is indigenous to Siberia but was not discovered until regular observations were made. There is also a possibility that this observation results from an expansion of the range of B. pomorum. We consider the evidence that our study coincided with a range expansion of the bumblebee species B. pomorum and B. sylvarum (Linnaeus,1761) near the end of 20th century. The distribution and abundance of B. pomorum in Russia and conservation efforts are also discussed.

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.

Citizen science data reveals the need for keeping garden plant recommendations up-to-date to help pollinators

Widespread concern over declines in pollinating insects has led to numerous recommendations of which “pollinator-friendly” plants to grow and help turn urban environments into valuable habitat for such important wildlife. Whilst communicated widely by organisations and readily taken up by gardeners, the provenance, accuracy, specificity and timeliness of such recommendations remain unclear. Here we use data (6429 records) gathered through a UK-wide citizen science programme (BeeWatch) to determine food plant use by the nations’ bumblebee species, and show that much of the plant use recorded does not reflect practitioner recommendations: correlation between the practitioners’ bumblebee-friendly plant list (376 plants compiled from 14 different sources) and BeeWatch records (334 plants) was low (r = 0.57), and only marginally higher than the correlation between BeeWatch records and the practitioners’ pollinator-friendly plant list (465 plants from 9 different sources; r = 0.52). We found pollinator-friendly plant lists to lack independence (correlation between practitioners’ bumblebee-friendly and pollinator-friendly lists: r = 0.75), appropriateness and precision, thus failing to recognise the non-binary nature of food-plant preference (bumblebees used many plants, but only in small quantities, e.g. lavender—the most popular plant in the BeeWatch database—constituted, at most, only 11% of records for any one bumblebee species) and stark differences therein among species and pollinator groups. We call for the provision and use of up-to-date dynamic planting recommendations driven by live (citizen science) data, with the possibility to specify pollinator species or group, to powerfully support transformative personal learning journeys and pollinator-friendly management of garden spaces.

Estimating possible bumblebee range shifts in response to climate and land cover changes

Wild bee decline has been reported worldwide. Some bumblebee species (Bombus spp.) have declined in Europe and North America, and their ranges have shrunk due to climate and land cover changes. In countries with limited historical and current occurrence data, it is often difficult to investigate bumblebee range shifts. Here we estimated the past/present distributions of six major bumblebee species in Japan with species distribution modeling using current occurrence data and past/present climate and land cover data. The differences identified between estimated past and present distributions indicate possible range shifts. The estimated ranges of B. diversus, B. hypocrita, B. ignitus, B. honshuensis, and B. beaticola shrank over the past 26 years, but that of B. ardens expanded. The lower altitudinal limits of the estimated ranges became higher as temperature increased. When focusing on the effects of land cover change, the estimated range of B. diversus slightly shrank due to an increase in forest area. Such increase in forest area may result from the abandonment of agricultural lands and the extension of the rotation time of planted coniferous forests and secondary forests. Managing old planted coniferous forests and secondary forests will be key to bumblebee conservation for adaptation to climate change.

Bumblebees moving up: shifts in elevation ranges in the Pyrenees over 115 years

In a warming climate, species are expected to shift their geographical ranges to higher elevations and latitudes, and if interacting species shift at different rates, networks may be disrupted. To quantify the effects of ongoing climate change, repeating historical biodiversity surveys is necessary. In this study, we compare the distribution of a plant–pollinator community between two surveys 115 years apart (1889 and 2005–06), reporting distribution patterns and changes observed for bumblebee species and bumblebee-visited plants in the Gavarnie-Gèdre commune in the Pyrenees, located in southwest Europe at the French–Spanish border. The region has warmed significantly over this period, alongside shifts in agricultural land use and forest. The composition of the bumblebee community shows relative stability, but we observed clear shifts to higher elevations for bumblebees (averaging 129 m) and plants (229 m) and provide preliminary evidence that some bumblebee species shift with the plants they visit. We also observe that some species have been able to occupy the same climate range in both periods by shifting elevation range. The results suggest the need for long-term monitoring to determine the role and impact of the different drivers of global change, especially in montane habitats where the impacts of climate changes are anticipated to be more extreme.

Effect of diet on incipient colony success for two long-tongued bumblebee species in the laboratory

Bumblebees (Bombus spp.) are ecologically and economically important pollinating insects and nutritional stress is one of the most significant factors causing their decline. However, our knowledge of the nutritional requirements of bumblebees is largely limited to just a small number of species that can be easily reared in the laboratory, so there is an important need to understand the nutritional requirements of a greater range of bumblebee species. In particular, the long-tongued, pocket maker species that have been intractable to laboratory rearing, yet are often of greatest conservation concern. Here, we compare the development and success of incipient colonies in two species of pocket maker bumblebees (B. pascuorum and B. hortorum) when fed either a less diverse or more diverse pollen diet. Our results show that both diets were sufficiently good for queens of both species to rear workers, but they performed significantly better for some variables on the less diverse diet. Our findings support previous work that suggests that a less diverse diet can be as good as a highly diverse mix in some respects. We also observed significant differences between species, demonstrating why we must not rely only on one or two model species to understand the effects of nutritional stress on bumblebee communities.

Contribution to the knowledge of the bumblebee fauna of Afghanistan (Hymenoptera, Apidae, Bombus Latreille)

Bumblebees (Hymenoptera: Apidae: genus Bombus Latreille, 1802) constitute an important group of pollinators for many wild plants and crops in north temperate regions and South America. Although knowledge of these insects has been increasing over the last decades, some geographic areas remain poorly studied and additions to the knowledge of their faunas are infrequent. Afghanistan is one example of a country that is currently underrepresented in the scientific literature despite its high species diversity. For this study, more than 420 new occurrence records were gathered for 17 bumblebee species belonging to all eight subgenera recorded in the country, including the first record of a species closely related to the B longipennis group. Additionally, the first standardized database for Afghan bees is launched, which we hope will be enriched in the future to allow further assessments of population trends for the bumblebees of Afghanistan. Finally, the previously published species records for the country are discussed considering the most recent taxonomic revisions of the genus and key perspectives are highlighted for further work in this understudied country and neighboring regions.