Bumblebees

This paper presents qualitative and quantitative analyses of the bumblebees' (Bom-bus) collection, which is kept in the Zoological Museum of Ivan Franko National University of Lviv. The collection includes 719 specimens of bumblebees, belonging to 23 species. The majority of these species were found in the western part of the territory of Ukraine (on the territory of eight regions), few specimens have been collected in Germany (1960) and in Egypt (2005). Unfortunately, there is a little part of specimens, which are lacking information on collecting locality. The basis of the collection is formed of the common and widespread bumblebee species, some rare species (Bombus argillaceus and B. muscorum) being available as well. The specimens have been collected during 1960–2017, the major part of the collection being made in the period od the last five years. The analysis of this collection shows us the species composition of the bumblebee fauna on the territory of Western Ukraine, and on the some others regions of Ukraine. This inventory will be a basis for a catalogue.

Climate change is threatening species and habitats. Altitudinal shifts uphill and negative population trends are commonly observed in altitude-related taxa. The bumblebee Bombus alpinus (Linnaeus, 1758) has a disjoint distribution restricted to Fennoscandia and the Alps, and is considered threatened. We studied the ecology and distribution of B. alpinus in the Alps, where the endemic subspecies Bombus alpinus helleri Dalla Torre 1882 is found, as a case-model because of its rarity, habitat, and mutual dependence with the ecosystem for pollination and resources. We developed species distribution models including both climatic and habitat variables to obtain the surface suitable for this subspecies and quantified its protected portion. Our analyses indicate that this bumblebee is restricted to the upper altitudes and has a narrow niche mainly related to the presence of glaciers, the cool temperature, a low temperature variation, and a specific range of precipitation. A strong altitudinal shift is also taking place probably due to climate change. After years of no changes in altitudinal distribution, its lowest altitudinal limit has moved up 479 m since the year 1984, while its upper altitudinal limit has remained unchanged. Over half of the suitable area in the Alps is included within protected areas, but conservation has not been planned yet. However, rare species with narrow niche, such as B. alpinus, are highly threatened by climate change. Potential short-term mitigation actions are discussed, including exchange of males between locations and integral protection of prairies in the vicinity of glaciers.

The decline of many bumblebee species (Bombus spp.) has been linked to an increased prevalence of pathogens caused by spillover from managed bees. Although poorly understood , RNA viruses are suspected of moving from managed honeybees (Apis mellifera) into wild bumblebees through shared floral resources. We examined if RNA viruses spillover from managed honeybees, the extent to which viruses are replicating within bumblebees, and the role of flowers in transmission. Prevalence and active infections of deformed wing virus (DWV) were higher in bumblebees collected near apiaries and when neighboring hon-eybees had high infection levels. We found no DWV in bumblebees where honeybee forag-ers and honeybee apiaries were absent. The prevalence of black queen cell virus (BQCV) was also higher in bumblebees collected near apiaries. Furthermore, we detected viruses on 19% of flowers, all of which were collected within apiaries. Our results corroborate the hypothesis that viruses are spilling over from managed honeybees to wild bumblebees and that flowers may be an important route for transmission.

High-resolution numerical simulations of a tethered model bumblebee in forward flight are performed superimposing homogeneous isotropic turbulent fluctuations to the uniform inflow. Despite tremendous variation in turbulence intensity, between 17% and 99% with respect to the mean flow, we do not find significant changes in cycle-averaged aerodynamic forces, moments, or flight power when averaged over realizations, compared to laminar inflow conditions. The variance of aerodynamic measures, however, significantly increases with increasing turbulence intensity, which may explain flight instabilities observed in freely flying bees.

Salvemos Nuestro Abejorro es una organización enfocada en la conservación del abejorro
nativo Bombus dahlbomii. A través de un modelo de ciencia ciudadana hemos recopilado
registros fotográficos de este insecto en todo el país. Se ha actualizado la información sobre
su distribución, permitiendo la postulación del abejorro como una especie con problemas de
conservación ante el Ministerio del Medio Ambiente. Adicionalmente hemos desarrollado
actividades de difusión para generar conocimiento y conciencia sobre la importancia de
conservar ésta especie

Bumble bees (Bombus Latrielle) are significant pollinators of flowering plants due to their large body size, abundant setae, and generalist foraging strategies. However, shared setal coloration patterns among closely and distantly related bumble bee species makes identification notoriously difficult. The advent of molecular genetic techniques has increased our understanding of bumble bee evolution and taxonomy, and enables effective conservation policy and management. Individuals belonging to the North American Bombus fervidus species-complex (SC) are homogenous in body structure but exhibit significant body color phenotype variation across their geographic distribution. Given the uncertainty of the genea-logical boundaries within the SC, some authors have synonymized all members of the B. fer-vidus SC within a single taxon, while others propose an alternative two taxa hypothesis. Operating under the phylogenetic species concept, our analysis supports the hypothesis that there are two independent lineages of bumble bees within the B. fervidus SC. With the current evidence, however, it is not possible to assign valid names to either of them, because both lineages include the color phenotypes found in the original species descriptions of B. fervidus and B. californicus. Cryptic speciation does not seem to be the product of Mü llerian mimicry between the clades, because diverging coloration patterns are observed when the distribution of the clades overlaps. Furthermore, within each lineage there is evidence for strong population differentiation that is correlated with geographic distribution rather than color phenotype. In our study, we demonstrate the importance of obtaining a broad sample of multiple populations when conducting lower-level phylogenetic analyses. In addition to improving our knowledge of bumble bee diversification patterns, characterizing the evolutionary history of these pollinators provides the foundation needed to guide contemporary conservation assessments and management strategies.

Acute lethal effect of the commercial formulation of the insecticides Imidacloprid, Spinosad y Thiocyclam hidrogenoxalate in Bombus atratus (Hymenoptera: Apidae) workers. The effect of insecticides on bees has gained great attention, however, there are few studies that explore this issue on Neotropical bees. Bombus atratus is a neotropical species broadly distributed in Colombia and is considered an important pol-linator of both Andean ecosystems and agroecosystems. However, as for many wild bees species, the effect of insecticides on B. atratus is unknow. In this study we determined the acute median lethal dose (LD50) of commercial formulations of insecticides Imidacloprid, Spinosad and Thiocyclam hydrogen oxalate, widely used in Colombia to control several pests of important crops. The LD50 was carried out by oral and contact routes, following and modifying the EPPO and OECD guidelines to perform LD50 on A. mellifera. We evaluated five doses for each route and insecticide, in a total of 25 medium-size workers for each dose by duplicate. Mortality was registered at 24, 48 and 72 hours after the experiment; and data were analyzed with the Probit regression model. For Imidacloprid, contacts and oral LD50 were 0.048 µg/bee and 0.010 µg/bee, respectively. For Thiocyclam hydrogen oxalate, topical and oral LD50 were 0.244 µg/bee and 0.056 µg/bee, respectively. For Spinosad, the oral LD50 corresponded to 0.28 µg/bee; it was not possible to establish the LD50 for the contact route. The Hazard Quotient (HQ) and Index of Relative Toxicity indicated that all three active ingredients are highly toxic. We discussed the risk of the insecticides use on B. atratus, considering their chemical nature. Rev. Biol. Trop. 64 (4): 1737-1745. Epub 2016 December 01.

The structure of bumblebee communities has been studied in some ecosystems of Kunashir Island and Southern Sakhalin. The island taxocenes include five to eight bumblebee species. Bombus hypnorum is dominant in the majority of habitats. In geothermal areas near hot springs on Kunashir, the families of this species develop more rapidly than in areas without geothermal heating.

The ecological success of social insects is frequently ascribed to improvements in task performance due to division of labour amongst workers. While much research has focused on improvements associated with lifetime task specialization, members of colonies can specialize on a given task over shorter time periods. Eusocial bees in particular must collect pollen and nectar rewards to survive, but most workers appear to mix collection of both rewards over their lifetimes. We asked whether bumblebees specialize over timescales shorter than their lifetime. We also explored factors that govern such patterns, and asked whether reward specialists made more foraging bouts than generalists. In particular, we described antennal morphology and size of all foragers in a single colony and related these factors to each forager's complete foraging history, obtained using radio frequency identification (RFID). Only a small proportion of foragers were lifetime specialists; nevertheless, >50% of foragers specialized daily on a given reward. Contrary to expectations, daily and lifetime reward specialists were not better foragers (being neither larger nor making more bouts); larger bees with more antennal olfactory sensilla made more bouts, but were not more specialized. We discuss causes and functions of short and long-term patterns of specialization for bumblebee colonies. Task specialization is a hallmark of insect societies 1,2. Eusocial bees, some of our most important pollinators, must engage in a variety of tasks over their lifetime, including nest construction, brood care, and foraging from flowers to feed themselves and their nest mates. Specialization on different foraging tasks in particular has been well studied (e.g., refs 3 and 4). Because switching between tasks can incur temporal, cognitive, and/or energetic costs, specialization is thought to maximize task efficiency 3–6. For instance, bees often have to learn new nectar collection routines each time they shift to a new plant species 3,7. Cognitive costs associated with learning and recalling such collection routines are thought to make it advantageous for foraging bees to specialize in the short term on a given plant species 3–8. In addition, individuals can vary in their task performance as a result of fixed physiological or morphological differences; for example, honeybees vary in their sucrose sensitivity 4,9. In fact, intrinsic differences among foragers are thought to explain lifetime patterns of specialization on the collection of nectar, water, and pollen in foraging honeybees 9,10. These and other studies suggest that patterns of foraging task specialization by individual worker bees might differ when we examine the short term (e.g., hours or days) versus the long-term (e.g., lifetime). Yet almost no research has examined specialization by the same foragers over different timescales. Patterns of foraging specialization over different timescales have important implications for how individuals and, for social bee species, colonies manage the collection of multiple floral rewards. The two most common floral rewards collected by bees are pollen and nectar 11,12. Flowering plants offer pollen and nectar in all combinations and qualities. For instance, the flowers of some plant species offer pollen and nectar, only pollen, only nectar, or even vary the availability of one or the other reward over the floral lifecycle or as a result of prior collection. Thus a forager might not always be able to collect pollen and nectar on a single floral visit (e.g., refs 13 and 14). Further, collecting both rewards during a single foraging bout may not be efficient if, for instance, the bee has to travel far to collect both rewards. In addition, colony needs vary over lifetime. Bees rely on nectar as their primary

A bumblebee community was studied at Pymvashor, the only thermal spring in North European Russia. The bumblebee fauna comprised 12 species, which is a large number when compared to other native tundra ecosystems. Most of the species recorded were ubiquitous, 3 were forest species and 2 were typical tundra species. The presence of the ubiquitous and forest species in the bumblebee community appears to be due to the landscape features and the perennial impact of the hot springs, under the influence of which specific extrazonal ecosystems arise that are different from those typical of the tundra zone.

The natural wind environment that volant insects encounter is unsteady and highly complex, posing significant flight-control and stability challenges. It is critical to understand the strategies insects employ to safely navigate in natural environments. We combined experiments on free flying bumblebees with high-fidelity numerical simulations and lower-order modeling to identify the mechanics that mediate insect flight in unsteady winds. We trained bumblebees to fly upwind towards an artificial flower in a wind tunnel under steady wind and in a von Kármán street formed in the wake of a cylinder. Analysis revealed that at lower frequencies in both steady and unsteady winds the bees mediated lateral movement with body roll - typical casting motion. Numerical simulations of a bumblebee in similar conditions permitted the separation of the passive and active components of the flight trajectories. Consequently, we derived simple mathematical models that describe these two motion components. Comparison between the free-flying live and modeled bees revealed a novel mechanism that enables bees to passively ride out high-frequency perturbations while performing active maneuvers at lower frequencies. The capacity of maintaining stability by combining passive and active modes at different timescales provides a viable means for animals and machines to tackle the challenges posed by complex airflows.

We examined the function of floral traits associated with buzz pollination through studies of Rhexia virginica (Melastomataceae) in the Muskoka region of Ontario, Canada. Controlled pollinations demonstrated that the species is self-compatible, but dependent on insects for pollen transfer. Bumble bees made 82 and 90% of observed insect visits to R. virginica in 1996 and 1997, respectively, and effectively buzzed flowers. Buzz pollination did not appear to be highly ‘‘specialized’’ since various species of bumble bee were capable of pollination, and pollen transfer efficiency appeared to be relatively low. Experimental manipulations provided little support for the hypothesis that the yellow color of melastome anthers mimics abundant pollen, thereby deceiving pollinators to visit regardless of whether most pollen has been removed. Fruit set averaged 52.6% among populations, owing largely to infrequent pollinator visits and pollen limitation. Flowers of R. virginica were infertile after a single day of anthesis, but petals were subsequently maintained for 1–2 d and stamens underwent a color change from bright yellow to red. Second-day flowers may function to increase floral display size and hence fertility, without a concomitant increase in pollen discounting. Studies of bumble bee foraging behavior and correlates of seed set provided indirect support for this hypothesis.

Pollinators frequently use complex motor routines to find and extract floral rewards. Studies of polli-nators foraging for nectar rewards indicate these routines are typically learned, and that constraints associated with learning and memory give pollinators incentive to continue foraging on these flowers. However, plants offer rewards besides nectar, including pollen, lipids and essential oils. In particular, bees use a complex motor routine termed floral sonication to extract pollen, their primary source of protein, from the more than 6% of flowering plant species (>22 000 species) that conceal pollen rewards within tube-like poricidal anthers. If floral sonication requires learning, this pollen extraction behaviour could contribute to floral fidelity. However, no studies have quantified the effect of experience on flower handling for bees extracting pollen from poricidal species. We therefore examined the degree to which floral sonication behaviour was modified by experience. We found that the key elements of the soni-cation motor routine appeared in full-blown form in a flower-naïve bee's first visit to a flower. We additionally found consistent, albeit modest, effects of experience on certain aspects of sonication behaviour. The latency to sonicate slightly decreased with experience. Bees also adjusted the length and amplitude of their sonication buzzes in response to pollen receipt. We conclude that the role of experience in foraging for concealed pollen rewards is different from that reported for nectar rewards. We offer an alternative explanation for its function in sonication. Finally, we discuss alternative hypotheses for the function of poricidal anthers and for how pollen-bearing plants may ensure floral fidelity even in the absence of a significant impact of experience on pollen extraction behaviour.

Species range expansions are crucial for understanding niche formation and the interaction with the environment. Here, we studied the bumblebee Bombus haematu-rus Kriechbaumer, 1870, a species historically distributed from northern Serbia through northern Iran which has very recently started expanding northwestward into Central Eu-rope without human-mediated dispersal (i.e., it is a natural spread). After updating the global distribution of this species, we investigated if niche shifts took place during this range expansion between newly colonized and historical areas. In addition, we have explored which climatic factors may have favored the natural range expansion of the species. Our results indicated that Bombus haematurus has colonized large territories in 7 Euro-pean countries outside the historical area in the period from the 1980s to 2018, a natural expansion over an area that equals 20% of the historical distribution. In addition, this bumblebee performs generalism in flower visitation and it occurs in different habitats, although a preference for forested areas clearly emerges. The land-use associated with the species in the colonized areas is similar to the historical distribution, indicating that no major niche shifts occurred during the spread. Furthermore, in recently colonized localities, the range expansion was associated with warming temperatures during the winter and also during both queen overwintering and emergence phases. These findings document a case of natural range expansion due to environmental change rather than due to niche shifts, and specifically they suggest that warmer winters could be linked to the process of natural colonization of new areas.