Diversity Of Bumblebees Research Articles

The effect of climatic variation on abundance and diversity of bumblebees: a ten years survey in a mountain hotspot

Even if climates play an evident role in the bumblebees distribution, at the present time, no research has been performed to test whether climatic parameters actually affect their abundance and diversity. For more than one decade (1999–2009), we monitored the bumblebee fauna of a mountain hotspot in the Eastern Pyrenees. We sampled each year, in July, the same hayfield habitat, resulting in the sampling of 28 species. We computed the correlation of the yearly abundance of the main species with several climatic parameters concerning temperature and precipitation. We separated the parameters measured during the bumblebee solitary phase and those measured during their social phase. Bumblebee fauna composition varied significantly over years. In the 13 species considered, the abundance of 9 was correlated with at least one climatic parameter. The lowest abundance of bumblebees was correlated with hot and dry conditions during the month of August the year before sampling (the nuptial time of the founders). The highest overall abundance of bumblebees was observed during the social phase in the rainy months. Across years, climatic parameters seem to have strongly affected the composition of bumblebee fauna. Our results seem to indicate that hot and dry weather represent serious threat for most bumblebee species. The potential effects of Global Warming are discussed: they may cause a severe reduction of the mountain bumblebee diversity.

Species Diversity of Bumblebees (Hymenoptera: Apidae) from Different Mountain Regions of Kashmir Himalayas

The species diversity of bumblebees was investigated in three provinces Jammu, Kashmir and Ladakh during 2007-2010. Bumblebee queens, workers and males were collected right from the commencement till to the end of flowering stage in all the three mountain regions. In total, 27 species of bumblebees were collected and identified, of which eleven species were common in the two regions, e.g., Kashmir and Ladakh. A list of species assemblages and abundance is provided in each of the mountain ranges. Species diversity of three regions was determined with Shannon-Weiner diversity index and evenness was calculated with indices of Pielou. The obtained results showed species diversity; evenness and species richness were more observable in Kashmir compared with Ladakh and Jammu. The three sample sites within the Kashmir Himalayas indicate significant differences in species diversity; the Kashmir region had higher species diversity and richness than the other regions. Most species of bumblebees were collected in altitudinal ranges of 3000-4000m. Four species viz. Bombus cornutus, B. parthenius, B. miniatus and B. morawitizianus are recorded for the first time from this region, while B. morawitizianus turn out to be the first record to the national list.Key words: Species Diversity; Bumblebees; Kashmir Himalayas.© 2012 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.doi: http://dx.doi.org/10.3329/jsr.v4i1.8815J. Sci. Res. 4 (1), 263-272 (2012)

The bumblebees of Gansu, Northwest China (Hymenoptera, Apidae)

Bumblebees are important pollinators for agricultural and natural ecosystems. Gansu province, China, is located in part of the greatest hotspot of bumblebee diversity worldwide, a region of very varied geomorphology and vegetation. We report on a recent field survey of the bumblebees of Gansu made between 2007–2010. A sample of 5941 bumblebee specimens from Gansu are assigned to 49 species. Two older specimens held in London add two more species to this list. Together, these 51 species belong to 10 subgenera of the genus Bombus, and 10 species (nearly one fifth of the fauna) are recorded for the first time from Gansu: B. asiaticus, B. bicoloratus, B. chinensis, B. coreanus, B. deuteronymus, B. expolitus, B. festivus, B. grahami, B. hypocrita, and B. opulentus. None of the species is endemic to Gansu. We provide distribution maps and describe variation in local species richness and abundance and list the food plants used in Gansu. The highest bumblebee richness for the province is in the southeastern mountains and Qinghai-Tibetan plateau in the southwest. We describe how the fauna of Gansu is transitional between the fauna of North China and the fauna of the more southern Sichuan-Himalayan region.

Management to enhance pollen and nectar resources for bumblebees and butterflies within intensively farmed landscapes

There have been serious global declines in diversity of bumblebees, butterflies and other pollinating insects. The most effective means of increasing abundance and diversity of bumblebees on farmland is to sow simple, low cost mixtures of dicotyledons rich in pollen and nectar, as prescribed under the UK agri-environment schemes. The potential benefits of this management prescription for butterflies are unknown. Similarly, more information is needed on how to manage this habitat to maximise the provision of pollen and nectar resources whilst protecting breeding habitat for butterflies. This study aimed to devise mixtures and cutting management regimes which address these issues. We found significant effects of seed mixture, timing and frequency of cutting, and removal of cut material on vegetation composition, flower resource availability and pollinators (the abundance, species richness and temporal distribution of butterflies and bumblebees, including males and queens, attracted to the mixtures). We recommend that nectar flower mixtures are refined by the inclusion of the best performing species to provide mid- and late-season forage resources (Trifolium spp., Lotus corniculatus and Centaurea nigra), and the removal of competitive grass species. Summer cutting in May or early June, with removal of herbage where possible, should be applied to half the patch to extend the flowering season, and minimise damage to butterfly breeding habitat. This should be accompanied by the typical autumn cut to the whole patch. Even with best management practice, such nectar flower mixtures are only effective for 3–4 years and this should be recognised in policies aimed at enhancing pollinator populations in agricultural landscapes.

Bumblebees (Hymenoptera: Apidae) of Remnant Grasslands in Arkansas

Abstract Recent evidence suggests that declines in bumblebee diversity have occurred on several continents. Assessments of regional faunas are critically needed in the United States to ascertain potential conservation needs. Over the course of seven years I conducted bumblebee surveys on the majority of Arkansas's native grassland remnants. The presence of seven of the eight bumblebee species previously recorded from the state was reconfirmed. Bombus variabilis was the only species not observed. Bombus bimaculatus, B. griseocollis, and B. pensylvanicus were the most frequently encountered bumblebee species. Bombus fervidus was rediscovered in the state after 90 years. Potential localized extirpations for B. auricomus, B. fraternus, and B. impatiens merit additional examination. The data generated represents a site-specific baseline for future assessments of species persistence in the state's remaining native grasslands.

Negligible impact of deer-induced habitat degradation on the genetic diversity of extant Bombus diversus populations in comparison with museum specimens

The genetic diversity of bumblebees can be adversely affected by habitat degradation. An overabundance of deer has altered the composition and diversity of herbaceous plants in many places of the world, resulting in decreases of herbaceous flowers. Populations of Bombus diversus may be strongly affected by this degradation of habitat in the Ashiu primary beech forest in Kyoto, Japan. To estimate the effects of deer browsing on B. diversus populations, we analyzed and compared the genetic diversity of the extant population in Ashiu to museum specimens collected prior to heavy deer browsing in Ashiu (1980s) and the extant population in Hyonosen primary beech forest in Tottori, Japan, which has not been as severely degraded by deer. We successfully amplified DNA from ~20-year-old museum specimens and determined the genetic diversity of B. diversus in Ashiu populations from the 1980s. Results were analyzed for indications of a bottleneck as well as estimates of Ne, allelic richness, rare allelic richness, expected heterozygosity, and the effective number of alleles. Our findings did not reveal clear evidence of degradation in genetic diversity of the extant Ashiu population compared to the museum specimens or to the Hyonosen population. Thus, the Ashiu population of B. diversus appears to have maintained a level of genetic diversity during 20 years irrespective of habitat degradation and the levels have been similar to that of the Hyonosen population.

Butterflies and bumblebees in greenways and sown wildflower strips in southern Sweden

Greenways have recently been established in some intensively farmed areas of South Sweden in order to enhance recreation opportunities and biodiversity, but the effects of these green structures on biodiversity have not yet been determined. In this study, greenways and experimental sown wildflower strips were investigated for butterfly and bumblebee diversity. In total, 1,769 butterflies of 18 species and 1,216 foraging bumblebees of eight species were recorded. Sown wildflower strips proved to support much higher abundances and species numbers of butterflies and bumblebees than greenways, with 86% of all butterflies and 83% of all bumblebees being observed in the sown flower strips. However, in both types of green structure mostly common species were found. Counts of flower visits showed that Knautia, Centaurea and Cirsium were the most commonly visited plant species. The greenways studied did not seem to fulfil their function of enhancing biodiversity—at least not for butterflies and bumblebees. However, these greenways could easily be improved for common bumblebee and butterfly species by sowing wildflower strips along their margins.

The bumblebees of Sichuan (Hymenoptera: Apidae, Bombini)

Bumblebees are important pollinators in mountainous regions. The highland region of Sichuan and Chongqing (together, Sichuan in the former broad sense) includes part of the greatest hotspot of bumblebee diversity worldwide, with half of the species of China and more than a fifth of the world's species. In this paper we present the first review of this diverse but particularly poorly known fauna, drawing on 6705 bees from selective samples made by the authors during field work and from museum collections, together with 1123 literature records (an overlapping set). Among this material we recognise 56 species that have 847 names (including infrasubspecific names). One new species, Bombus (Pyrobombus) wangae, is described from Sichuan and Gansu. B. laesus is found to have a colour pattern in this part of its range that was previously undescribed. Six species are recorded from the Sichuan‐Chongqing region for the first time (B. avanus, B. branickii, B. difficillimus B. humilis, B. norvegicus, B. tibetanus), of which B. avanus is only the second published record worldwide. One species, B. braccatus, is endemic to Sichuan and is confirmed as extant in 2005. We provide diagnoses and keys to species for both sexes. Colour variation is described, distributions within the Sichuan‐Chongqing region are mapped, altitudinal and seasonal activity are plotted, and the authors’ records of food plants are listed.

Bumble Bees (Bombus spp) along a Gradient of Increasing Urbanization

BackgroundBumble bees and other wild bees are important pollinators of wild flowers and several cultivated crop plants, and have declined in diversity and abundance during the last decades. The main cause of the decline is believed to be habitat destruction and fragmentation associated with urbanization and agricultural intensification. Urbanization is a process that involves dramatic and persistent changes of the landscape, increasing the amount of built-up areas while decreasing the amount of green areas. However, urban green areas can also provide suitable alternative habitats for wild bees.Methodology/Principal FindingsWe studied bumble bees in allotment gardens, i.e. intensively managed flower rich green areas, along a gradient of urbanization from the inner city of Stockholm towards more rural (periurban) areas. Keeping habitat quality similar along the urbanization gradient allowed us to separate the effect of landscape change (e.g. proportion impervious surface) from variation in habitat quality. Bumble bee diversity (after rarefaction to 25 individuals) decreased with increasing urbanization, from around eight species on sites in more rural areas to between five and six species in urban allotment gardens. Bumble bee abundance and species composition were most affected by qualities related to the management of the allotment areas, such as local flower abundance. The variability in bumble bee visits between allotment gardens was higher in an urban than in a periurban context, particularly among small and long-tongued bumble bee species.Conclusions/SignificanceOur results suggest that allotment gardens and other urban green areas can serve as important alternatives to natural habitats for many bumble bee species, but that the surrounding urban landscape influences how many species that will be present. The higher variability in abundance of certain species in the most urban areas may indicate a weaker reliability of the ecosystem service pollination in areas strongly influenced by human activity.

DNA amplification from pin-mounted bumble bees (Bombus) in a museum collection: effects of fragment size and specimen age on successful PCR

Historic data in the form of pinned specimens in entomological collections offer the potential to determine trends in genetic diversity of bumble bees (Bombus). We screened eight microsatellite loci in pinned bumble bee specimens from the U. S. National Pollinating Insects Collection. We tested three species (Bombus appositus, Bombus huntii and Bombus occidentalis) representing three subgenera of bumble bees (Subterraneobombus, Pyrobombus and Bombus sensu stricto) respectively. Bombus occidentalis is a species of particular concern for conservation biologists. Single mid-legs of ninety-six individuals from each species were assayed to determine microsatellite amplification success rates of historic material in a museum collection. Microsatellite alleles amplified in specimens up to 101 years old, but the rate of amplification success was significantly lower in material over 60 years of age. Loci with shorter allele sizes amplified more frequently than relatively longer alleles in samples from all age classes. We correlate the age of specimens to the age at which loci fail to amplify and discuss potential impacts of using certain markers for population genetic studies of museum specimens.

Bumblebee diversity and abundance in the Iranian Alborz Mountains (Hymenoptera: Apidae)

In this survey, which extended from February to September of 2005 to 2007, bumblebee queens, workers and males were collected from five provinces in the north and northwest of Iran in the Central Alborz and Sabalan. In total, 26 species of bumblebees were collected and identified. Overall, 21 species were collected from the Sabalan while 16 species were collected from the Central Alborz Mountains. A list of species assemblages and abundance is provided for the various provinces in each of the mountain ranges. Although the number of specimens collected from the Central Alborz (867 specimens) was about three times higher than the Sabalan region (264 specimens), Sabalan had 80.7% and Alborz 61.5% of all species. Results from rarefaction analysis (species accumulation curves) indicated that the Sabalan and the Central Alborz Mountains do not differ in bumblebee diversity. Moreover, the two sample sites within the Sabalan Mountains do not differ in species diversity while in the Central Alborz Mountains samples sites indicate significant differences in species diversity. In this region, the Qazvin region had higher species diversity than the other regions. Most species of bumblebee were collected in altitudinal ranges of 1500–2500m.

Decline of bumble bees ( Bombus) in the North American Midwest

Declines in many bumble bee species have been documented in Europe raising several ecological and economic concerns. The nature and extent of bumble bee decline in North America is poorly understood due mainly to a lack of baseline and long-term data. Museum collections provide excellent sources of information on past and current species distributions, which can be used to infer changes in the composition of insect communities. Using the Illinois Natural History Survey’s electronic database of Hymenoptera and a recent biodiversity survey of historically sampled localities, we were able to examine changes in the richness and distribution of the bumble bee fauna of Illinois over the last century. We found that bumble bee species richness declined substantially during the middle of the century (1940–1960). Four species were locally extirpated: Bombus borealis, Bombus ternarius, Bombus terricola and Bombus variabilis. The ranges of Bombus affinis, Bombus fraternus, Bombus pensylvanicus and Bombus vagans have also decreased in Illinois. Our analyses also indicated that current bumble bee diversity is highest in northern Illinois, where conservation efforts would be most productive. Our study demonstrates that half of the bumble bee species found historically in Illinois have been locally extirpated or have suffered declines, supporting observations of broader declines in North America. Major declines in the bumble bee fauna coincided with large-scale agricultural intensification in Illinois between 1940 and 1960. Attempts to conserve bumble bees in Illinois should involve wildlife-friendly approaches to agriculture, such as increasing agricultural land set-asides and hedgerows, and employing integrated pest management.

The effect of grazing on bumblebees in the high rangelands of the eastern Tibetan Plateau of Sichuan

Many Tibetans who were formerly nomadic yak herders are settling near towns. However, yak remain a traditional symbol of wealth, which can lead to increased local stocking densities and severe over-grazing. We used belt-transect counts to study the area around Hongyuan in Sichuan. We find that intensive summer grazing significantly reduces the vegetation height and is associated with significant reductions in bumblebee-food-plant abundance and bumblebee diversity. For the significantly reduced bumblebee species, we identify the most frequently used and preferred bumblebee-food plants. For the food plants, we identify changes in absolute flower availability and changes in bumblebee visits. In particular, reductions in the bumblebees Bombus supremus, B. filchnerae, B. humilis and B. impetuosus are associated with reductions in flowers of the food plants Hedysarum and Saussurea.

Role of organic and conventional field boundaries on boreal bumblebees and butterflies

This study examined how field boundary habitat quality and farming system (organic or conventional) affect species richness and abundance of diurnal lepidopterans and bumblebees in boreal agricultural landscapes. The results showed positive effects of field boundary area on lepidopteran diversity, as well as positive effects of nectar flower abundance on lepidopterans and bumblebee abundance. Organic farming did not show any significant effects on lepidopteran diversity. The results suggested that a successful conservation strategy for lepidopterans occurring in boreal agroecosystems depend on proper management of field boundaries, irrespective of farming regime. As bumblebee diversity tended to be higher at organic plots it is concluded that these important pollinators might be able to react on even small changes in habitat quality of cultivated lands. The results concord with a general hypothesis that effects of organic farming might be overpowered by effects of landscape structure in heterogeneous landscapes.

Comparing the efficacy of agri‐environment schemes to enhance bumble bee abundance and diversity on arable field margins

Summary Declines in abundance and diversity of bumble bees (Bombus spp.) in Europe have been linked to agricultural intensification and the resulting loss of suitable foraging and nesting habitats. Environmental Stewardship (ES) is a new scheme in England offering the opportunity to restore habitats of value for these important pollinators to agricultural land. Scientific evaluation of the options prescribed within the scheme is essential to ensure that their objectives are met and that the benefits can be realized by the full bumble bee species assemblage. We compared the efficacy of different ES options for field margins on arable land in enhancing the abundance and diversity of flowering resources and foraging bumble bees. Our study was conducted over 3 years using a multisite experiment. Overall, uncropped margins sown with mixtures containing nectar and pollen‐producing plants were more effective in providing bumble bee forage than margins sown with a grass mix, allowed to regenerate naturally or managed as conservation headlands. A mixture of agricultural legumes established quickly and attracted on average the highest total abundance and diversity of bumble bees, including the rare long‐tongued species Bombus ruderatus and Bombus muscorum. However, marked differences were observed between species and sexes in their responses to field margin management over time. A diverse mixture of native wildflowers attracted more of the shorter‐tongued Bombus spp. and provided greater continuity of forage resources, especially early in the season. Allowing Cirsium spp. to flower on such margins also increased their attractiveness to male bumble bees. Synthesis and applications. Our results suggest that the legume‐based ‘pollen and nectar flower mix’, as prescribed under Entry Level Stewardship in England, can quickly provide a highly attractive forage resource for bumble bees, but that issues of seasonal flowering phenology and longevity of the mixture need to be addressed. Establishment of ‘floristically enhanced margins’ under Higher Level Stewardship will be important to provide diverse perennial communities of forage plants and to support a greater range of Bombus spp. and other pollinators. The population‐level responses of bumble bees to introduced seed mixtures and other agri‐environment options require further study in order to maximize the benefits of such schemes in intensively farmed landscapes.

Bumble Bee (Hymenoptera: Apidae) Diversity and Abundance in Tallgrass Prairie Patches: Effects of Local and Landscape Floral Resources

Conservation of biodiversity recently has focused on the importance of pollinator services for the preservation of threatened plant species in fragmented landscapes such as the tallgrass prairie biome. In this study, we assessed the insuence of local and landscape soral resource diversity and abundance on bumble bee (Bombus Latreille) diversity and abundance at eight tallgrass prairie sites in Iowa. We calculated a landscape soral resource index (LRI) for areas within 500- and 700-m radii of each site based on the density and diversity of sowering plant species in polygons of different landscape elements. LRI values, areas of each landscape habitat type, and the diversity and abundance of bumble beeÐ used sowering ramets at each site were compared with bumble bee diversity and abundance at the site. Bumble bee diversity was best predicted by a model including the LRI of grasslands surrounding sites at 500 m, which explained most of the variance, and the abundance of bumble beeÐvisited plants at the site. Bumble bee abundance was best predicted by a model including the percent of the landscape in grasslands at the 700-m radius, which explained most of the variance, and the abundance of bumble beeÐvisited plants at the site. Our results reveal that bumble bee diversity at tallgrass prairie patches is insuenced by the availability of resources in the landscape, particularly in grasslands, and to a lesser extent by site characteristics, indicating the importance of spatial scale for creating successful pollinator management plans in fragmented landscapes.

The relationship between the abundances of bumblebees and honeybees in a native habitat

Abstract. 1. The western honeybee, Apis mellifera, has been introduced to many parts of the world and is sometimes purported to be detrimental to native bees because it reduces their food base. It is seldom viewed in this light in Europe; however, when beekeepers maintain very high bee densities, the species could also be displacing insects in its native European range by reducing the resource base.2. In England, populations of bumblebees (Bombus Latr. Hym.) have been decreasing both in terms of diversity and abundance, mainly because of a loss of habitat resulting from agricultural intensification. The impact of competition from other flower feeders is largely unknown.3. Nineteen dry lowland heaths in southern England were sampled once for honeybees and bumblebees. Honeybee abundance varied from 4 to 81 bees per 100 m2 (mean = 30.89, median = 23), whereas bumblebees varied from 2 to 17 individuals per 100 m2 (mean = 8.26, median = 7), belonging to between one and five species. There was a negative association between honeybee and bumblebee abundance but there was no apparent relationship between honeybee abundance and bumblebee diversity.4. The Bray–Curtis coefficient was used to compare the similarity in honeybee and bumblebee floral host breadth at these 19 sites. The coefficient was negatively associated with honeybee abundance: thus where honeybees were most abundant, bumblebees were fewer and/or foraged on different flower species.5. Foraging host breadth was also examined at four heathlands over a field season (April to September). No association between honeybee abundance and foraging host breadth was found for short‐tongued bees, although there was some evidence for a change in floral host breadth for long‐tongued bees.6. It is concluded that the impact of honeybees on bumblebees is complex. Although competition between the two species cannot be ruled out, it is perhaps equally likely that bumblebees decline in response to other factors, and that honeybees move independently of this decline.

Species‐Richness Correlations of Six Different Taxa in Swedish Seminatural Grasslands

Abstract: An important question in conservation biology is whether the biodiversity of different taxa is correlated. We studied the extent to which the number of species of six different taxa—plants, birds, butterflies, bumblebees, ground beetles, and dung beetles—in 31 Swedish seminatural grasslands covary, and whether species diversity can be related to habitat variables. During 1996 and 1997, we surveyed plants and animals with appropriate techniques for each taxa and mapped the grassland habitat. In general, correlations between taxa were few. Grassland plant diversity (currently used as an indicator for conservation value) was only significantly positively correlated to total bird diversity. Bumblebee diversity was significantly positively related to both total and grassland butterflies, whereas there was a significant negative relationship between grassland birds and dung beetles. Plants, birds, bumblebees, and butterflies showed significant similarities in patterns of species composition, as did birds, butterflies, grassland butterflies, and ground beetles. The total number of plants and both subsets of birds (total and grassland) were significantly positively related to area, whereas there was a significant negative association between area and dung‐beetle diversity. The diversity of both butterflies and bumblebees was significantly negatively related to the proportion of short‐grazed field layer. Bumblebees showed a positive relationship with junipers, whereas ground beetles and grassland birds were negatively associated with trees. The total number of bird species was positively influenced by the occurrence of shrubs. Our results suggest that neither the species richness of grassland plants nor that of any other of the surveyed taxa can be used as an indicator for total biodiversity in seminatural grasslands. The lack of similar patterns of species composition among taxa also makes it difficult to define functional groups with similar habitat demands. Until we have more detailed knowledge of the demands of species and taxa, it is important that we direct management efforts so that we provide a wide spectrum of grassland characteristics.

Bumble Bee Colonization, Extinction, and Reproduction in Subalpine Meadows in Northeastern Utah

The distributional patterns of six bumble bee (Bombus) species in discrete subalpine meadows in Utah were studied over the course of a summer. Data on the movements of individuals were obtained through mark—recapture studies of queens during nest initiation and of workers later in the summer. Censuses of the species and abundance of bumble bees and flowers in sample quadrats of 20 meadows revealed patterns of diversity, colony extinction (inferred from the absence of a species after it had been previously recorded in the meadow), and production of new reproductives. The results suggest that the number and diversity of queens that colonize a meadow in early summer is a function of meadow area. In mid to late season, after nest sites have been chosen and colonies established, meadow floristics (flower composition) governs within—meadow Bombus species composition and the persistence, ontogeny, and reproduction of bumble bee colonies. Workers appear not to utilize flowers outside the meadow where their colony is located. Specific results were that (1) mid— to late—summer bumble bee diversity was best correlated with meadow floristics, (2) flower compositions in meadows where local extinctions of Bombus occurred differed markedly from those where all species persisted, (3) the distribution of new reproductives among the meadows was independent of bombus species composition, and (4) late—season reproductive timing of Bombus flavifrons appeared to be a function of floristic composition and, particularly, nectar availability. These results underscore the importance of flower resources while downplaying the role of interactions among Bombus colonies and species in accounting for patterns of species persistence and colony reproduction.