Atypical secretions of the male cephalic labial glands in bumblebees: the case of Bombus (Rhodobombus) mesomelas Gerstaecker (Hymenoptera, Apidae)

In bumblebees, the male secretion of the cephalic labial gland is species-specific. It is highly involved in the nuptial behavior, acting as a sexual attracting pheromone. Therefore, it is also used to accurately identify the species. In contrast to this common scheme, the secretions of Bombus mesomelas are found to be strongly reduced and do not include the most volatile compounds that are present in the secretions of all the other studied bumblebee species. These secretions correspond to cuticular hydrocarbons that can be found in all bumblebee species. This was also the case for another bumblebee species from the same Rhodobombus subgenus: Bombus pomorum. This atypical composition of the male cephalic labial gland secretions seems to indicate that, at least for these two species of Rhodobombus, these secretions are not used to attract virgin females from a long distance, as it is the case for all the other bumblebee species studied.     

Using citizen science to monitor Bombus populations in the UK: nesting ecology and relative abundance in the urban environment

Citizen science can provide a valuable tool for collecting large quantities of ecological data over a larger geographic area than would otherwise be possible. Here, data were collected on 1,022 bumblebee nests by means of a public survey in which participants were asked to record attributes of bumblebee nests discovered in their gardens. All commonly reported species appeared to be generalist in their nest site selection and though species-specific differences in nest site choice were evident, there was a high degree of overlap in nesting habitat between most species. There was little evidence supporting the hypothesis that bumblebees tend to nest in the same site in consecutive years. A comparison of the contributions made by different species to the total nests reported in this and previous similar surveys suggests that the common bumblebee species Bombus pascuorum may have declined over the past 20?years relative to other species, comprising ~21% of colonies discovered in a survey conducted in 1989–1991, but just 8–9% of colonies in 2007–2009. This was accompanied by a reduction in the proportion of nests on the ground surface (the preferred position of this species). This is the first quantitative evidence of potential declines in the one of the UK’s ‘big six’ common bumblebee species.     

Simple and farmer-friendly bumblebee conservation: Straw bales as nest sites in agricultural landscapes

Many bumblebee species are declining due to a loss of semi-natural habitats in agricultural landscapes resulting in diminished forage and nest sites. Anecdotal experience indicates that bumblebees nest in straw bales, but scientific evidence is lacking. We spent 250 h screening for bumblebee nests in 1255 straw bales and ten straw stacks belonging to 58 farms in two intensively farmed Swedish regions and recorded nests, nest traffic, and straw characteristics. We supplemented the straw screening with screening of control areas, without straw, that were selected in similar environments as the areas with straw. We observed 45 bumblebee nests (including potential nests where a single bumblebee flew in or out of the straw) of eight species/species groups, including one red-listed, in or directly adjacent to the straw at 26 of the farms. Nests were mainly found in partly decayed straw and bales placed together. We found no nests in control areas. Based on our results, we suggest that straw can be used as an easy, cheap and efficient intervention to increase the availability of bumblebee nest sites in agricultural landscapes. Considering the costs and benefits of the alternatives, we conclude that straw addition has advantages over commercial bumblebee colonies for crop pollination purposes and over artificial nest boxes for conservation purposes.     

Distribution and forage use of exotic bumblebees in South Island, New Zealand

The rapid decline in bumblebee populations within Europe has been linked to habitat loss through agricultural intensification, and a consequential reduction in the availability of preferred forage plants. The successful introduction of four European Bombus species to the South Island of New Zealand from England (in 1885 and 1906) provides an opportunity to determine how important different forage plants (also introduced from the U.K.) are to two severely threatened European bumblebee species (Bombus ruderatus and B. subterraneus). In January 2003 we conducted a survey of bumblebee populations across 70 sites in the central and southern South Island, recording which plant species were being used as pollen and nectar sources for each Bombus species. All four bumblebee species showed a clear preference for plants of European origin. Only B. terrestris, the most polylectic species, was recorded feeding on native plant species. The longer-tongued bumblebees, B. hortorum, B. ruderatus, and B. subterraneus, foraged predominantly on just two plant species; Trifolium pratense for both nectar and pollen, and Echium vulgare for nectar. These plant species are now declining in abundance in the U.K. Our results provide support for the hypothesis that the loss of flower-rich meadows, particularly those containing populations of Fabaceae species with long corollae, is responsible for the decline of bumblebee species across Europe. Comparison with earlier bumblebee surveys suggests that long-tongued bumblebees may also be in decline in New Zealand, particularly B. subterraneus which is now very localised and scarce.     

海南鹦哥岭自然保护区两栖动物区系及属种海南新纪录

2003～2008年,多次对海南省中部山区鹦哥岭自然保护区及其周边进行两栖爬行动物多样性调查,共记录到39种两栖动物(有尾类1种,无尾类38种),隶属于2目7科23属。其中,包括海南属种新纪录小姬蛙属的德力小姬蛙(Micryletta inornata)和新纪录种马来棱皮树蛙(Theloderma asperum)。另外,还采集到2个待定种,分别为小蟾属物种(Parapelophryne sp.)和一种大型的棱皮树蛙属物种(Theloderma sp.),但需要进一步研究鉴定。鹦哥岭调查中共记录到39种(88.6%)已知在海南有分布的两栖动物,包括11个海南特有种,占海南13种特有两栖动物的84.6%,这说明鹦哥岭自然保护区在海南岛两栖动物多样性的保护中具有不可替代的地位。     

熊蜂生物学及种群影响因素研究进展

熊蜂是膜翅目蜜蜂科熊蜂属内物种的统称,全球约有250种,中国已知125种,是全球熊蜂资源最丰富的国家。该类昆虫是众多野生植物和农作物的重要传粉者,对维持自然生态系统和农业粮食生产极为重要。一些群势强、易于人工饲养的熊蜂物种被开发利用,为多种目标作物授粉。本文介绍了熊蜂的生物学特性和授粉应用现状,综述了栖息地丧失、气候变化、病原体传播、外来物种入侵及化学农药等多重因素对熊蜂种群的影响,并从熊蜂的应用基础研究、资源保护及授粉经济价值评估等多方面作了展望,旨在为中国本土熊蜂的保护、应用和生态功能研究提供参考。     

Comparative studies on glycerol 3-phosphate dehydrogenase in bees and wasps

Electrophoresis of tissue extracts has shown the presence of multiple electrophoretic forms of glycerol 3-phosphate dehydrogenase (EC 1.1.1.8) in many Hymenoptera. The patterns are most complex in the two bumblebee genera, Bombus and Psithyrus, where from five to six variants are observed.Homogeneous preparations of the major flight muscle variant of glycerol 3-phosphate dehydrogenase have been isolated from thoraces of three bumblebee species and of yellow jacket. The amino acid compositions of these four enzymes plus that from the honeybee have been determined and compared.The Michaelis constant for dihydroxyacetone phosphate was measured for the honeybee, bumblebee, and yellow jacket enzymes. Differences were observed between species but not between bumblebee isozymes.B. nevadensis glycerol 3-phosphate dehydrogenase binds reversibly to both B. nevadensis and honeybee actin. The alar-muscular variants bind more strongly than the omniregional variants.     

Environmentally-friendly and organic management practices enable complementary diversification of plant–bumblebee food webs

Plant and pollinator diversity have declined concurrently in Europe in the last half century. We studied plant–bumblebee food webs to understand the effects of two agri-environmental schemes (AES, organic farming and environmentally-friendly management practice) vs. conventional farming as control group, landscape structure (heterogeneous vs. homogeneous landscapes) and seasonality (June, July, and August) interactions using Estonian AES monitoring data. In the summer of 2014, we observed foraging bumblebees (20 species) on 64 farms that varied in agricultural management and landscape structure, yielding a total of 2303 flower visits on 76 plant species. We found that both management practice and landscape structure influenced the generality (redundancy in the use of flower resources) of food webs. In homogeneous landscapes, environmentally-friendly management practices, including restrictions on the application of glyphosates, enhancement of bumblebee habitats, such as permanent grassland field margins, the allocation of a minimum of 15% of arable land (including rotational grasslands) to legumes, contributed to a higher number of visited plant species (generality) in July, whereas organic farming did so in August. Therefore, both environmentally-friendly and organic management practices are needed to support plant–bumblebee food webs in agricultural landscapes. Food web generality and diversity (Shannon index) are affected by a significant interaction between landscape structure and seasonality: food web diversity varied in homogeneous landscapes between the three different survey months, whereas food webs were more diverse in heterogeneous landscapes. We did not find any significant interaction effect of management, landscape structure and seasonality on linkage density and vulnerability. A full list of the most visited plant species by bumblebees based on species-specific flower visitation was also assembled. In homogeneous landscapes, resource limitation is an issue for bumblebees in certain time periods. For supporting bumblebees in the agricultural landscapes, avoiding resource limitation is important and this can be secured with a combination of AES management practices.     

Structure in seven bumblebee communities in eastern Finland in relation to resource availability

The structure of seven local bumblebee communities was studied in eastern Finland. The number of species in the study sites varied from 5 to 10, 11 being the number in the species pool. Most of the species (queens) had proboscis lengths of 8–11 mm. When floral resources were analysed on the basis of corolla tube depths, a group was found between 4 and 8 mm. In terms of flower utilization, species with similar proboscises had higher pairwise niche overlaps than species differing by their proboscis lengths.
Spacing between neighbouring species along the proboscis length dimension was not more uniform in the realized communities than what was expected on the basis of random draws from the local species pool. The results were the same for all species observed in the communities and for the abundant species only (frequency >5%), although competition among species in the latter group is expected to be more intense.
When the structure of bumblebee communities and of floral resources was expressed in terms of diversity of proboscis lengths and corolla tube depths, respectively, a positive correlation was found. Data suggest that species with similar proboscis tend to co-occur on fields with availability of appropriate corolla tubes.     

Spatial and temporal variations in floral resource availability affect bumblebee communities in heathlands

Modifications of landscape structure and composition can decrease the availability of floral resources, resulting in the decline of many pollinator species, including bumblebees. These declines may have significant ecological consequences, because bumblebees pollinate a large range of plant species. Our study was carried out in heathlands, open semi-natural habitats that have decreased considerably due to human activities. We analysed how floral resources affect bumblebee communities throughout the colony lifetime at three scales: plot scale, heathland patch scale, and landscape scale. Floral density at the plot scale and spruce plantations at the landscape scale influenced bumblebee communities. The abundance of bumblebees on ericaceous species was higher when the landscape included a substantial proportion of unsuitable foraging habitat (i.e., spruce plantations). Both life history traits and colony life cycle stage influenced bumblebee responses to the availability of floral resources. Bumblebees were more affected by floral resources during the colony development phase than during the nest-foundation or mating phases. Moreover, bumblebees of species that form large colonies needed larger quantities of favourable foraging habitat, compared with small-colony bees, and their proportion decreased in habitats dominated by spruce plantations. In conclusion, the conservation of plant–bumblebee interactions will require management at a larger spatial scale than the restricted protected habitats. Moreover, at the landscape scale, both quantity of favourable foraging patches and their ecological continuity are important to conserve both small- and large- colony species.     

High-resolution distribution of bumblebees (Bombus spp.) in a mountain area marked by agricultural decline

Since the 1980s, bumblebee species have declined in Europe, partly because of agricultural intensification. Yet little is known about the potential consequences of agricultural decline on bumblebees. In most mountainous areas, agricultural decline from rural exodus is acute and alters landscapes as much as intensive farming. Our study aims at providing a quantitative assessment of agricultural decline through its impact on landscapes, and at characterising bumblebee assemblages associated with land-use types of mountain regions. The studied area (6.2 km²) belongs to the Eyne’s valley in the French Pyrenees, known to host the exceptional number of 33 bumblebee species of the 45 found in continental France. We compare aerial photographs from 1953 and 2000 to quantify agricultural decline. We cross a bumblebee database (2849 observations) with land-use types interpreted from aerial photographs from 2000. Comparison of land-use maps from 1953 and 2000 reveals a strong progression of woodland and urbanised areas, and a decline of agricultural land (pastures and crops), except for hayfields. Spatial correlations between low altitude agro-pastoral structure and the occurrence of bumblebee species shows that bumblebee specific richness is highest in agro-pastoral land-uses (pastures and hayfields) and in the ski area, and poorest in woodland and urbanised areas. Urbanisation and agricultural decline, through increased woodland areas, could lead to a loss of bumblebee diversity in the future. To preserve high bumblebee richness, it is crucial to design measures to maintain open land habitats and the landscape’s spatial heterogeneity through agro-pastoral practices.     

吉林莫莫格国家级自然保护区的鸟类资源

2003年7月~2006年5月对吉林莫莫格国家级自然保护区的鸟类进行了调查,并结合历史文献,确认保护区有鸟类298种,其中非雀形目鸟类172种,雀形目鸟类126种。该保护区的鸟类以旅鸟和夏候鸟为主,占保护区鸟类总数的84%(旅鸟52%、夏候鸟32%、留鸟11%、冬候鸟5%)。在128种繁殖鸟类中,古北界种类占73.44%,东洋界种类占6.25%,广布种占20.31%,可见古北界种类占优势。在保护区内记录到国家Ⅰ、Ⅱ级重点保护鸟类50种。     

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.     

中国熊蜂多样性、人工利用与保护策略

熊蜂是众多野生植物和农作物的重要传粉者, 在维持自然和农业生态系统平衡中发挥着十分重要的作用。中国地形多样、植被丰富, 是全球熊蜂多样性的热点地区, 但过去缺乏系统调查研究, 中国熊蜂多样性现状及其利用特性不详。本文介绍了近20年在中国熊蜂资源系统调查及其人工利用方面取得的主要研究结果: (1) 2002-2017年采集熊蜂标本5万余号, 先后揭示了一系列疑难类群的分类地位, 确认中国已知熊蜂125种, 占全球熊蜂已知物种总数的50%, 表明中国是全球熊蜂物种资源最丰富的国家; (2)首次报道了中国熊蜂物种名录, 其中22种为中国特有种。我国青藏高原东部向黄土高原、秦岭山地和四川盆地过渡的地带, 是全球熊蜂多样性分布中心; (3) 1998-2017年, 明亮熊蜂(Bombus lucorum)、密林熊蜂(B. patagiatus)、红光熊蜂(B. ignitus)、火红熊蜂(B. pyrosoma)、重黄熊蜂(B. picipes)和兰州熊蜂(B. lantschouensis) 6种本土熊蜂先后被驯养成功, 其中密林熊蜂和兰州熊蜂的繁殖性状优良, 已应用于我国设施作物传粉服务。同时, 我们从栖息地、食物资源、外来物种、农药使用等方面提出了保护中国熊蜂资源的策略, 以期为野生传粉昆虫特别是熊蜂资源的保护与可持续利用提供参考资料。     

Reconstructing the pollinator community and predicting seed set from hydrocarbon footprints on flowers

The measurement of insect visits to flowers is essential for basic and applied pollination ecology, but is often fraught with difficulty. Floral visitation is highly variable and observational studies are limited in scope due to the considerable time needed to acquire reliable data. Our study investigates whether the analysis of hydrocarbon residues (footprints) deposited by insects during flower visits allows the reconstruction of the visitor community and the prediction of seed set for large numbers of plants. In three consecutive years we recorded bumblebee visitation to wild plants of comfrey, Symphytum officinale, and later used gas chromatography/mass spectrometry (GC/MS) to quantify bumblebee-derived unsaturated hydrocarbons (UHCs) extracted from flowers. The UHCs washed from corollae were most similar to the tarsal UHC profile of the most abundant bumblebee species, Bombus pascuorum, in all 3 years. The species compositions of the bumblebee communities estimated from UHCs on flowers were also similar to those actually observed. There was a significant positive correlation between the observed number of visits by each of three bumblebee species (contributing 3–68% of the flower visits) and the estimated number of visits based on UHC profiles. Furthermore, significant correlations were obtained separately for workers and drones of two species. Seed set of comfrey plants was positively correlated with overall bumblebee visitation and the total amount of UHCs on flowers, suggesting the potential for pollen limitation. We suggest that quantifying cumulative footprint hydrocarbons provides a novel way to assess floral visitation by insects, and that this method can be used to predict seed set in pollen-limited plants.     

Reconstructing the pollinator community and predicting seed set from hydrocarbon footprints on flowers

The measurement of insect visits to flowers is essential in basic and applied pollination ecology studies but often fraught with difficulty. Floral visitation is highly variable, and observational studies are limited in scope due to the considerable time necessary to acquire reliable data. The aim of our study was to investigate whether the analysis of hydrocarbon residues (footprints) deposited by insects during flower visits would allow reconstruction of the visitor community and prediction of seed set for large numbers of plants. In 3 consecutive years, we recorded bumblebee visitation to wild plants of comfrey, Symphytum officinale, and later used gas chromatography/mass spectrometry (GC/MS) to quantify bumblebee-derived unsaturated hydrocarbons (UHCs) extracted from flowers. We found that the UHCs washed from corollas were most similar to the tarsal UHC profile of the most abundant bumblebee species, Bombus pascuorum, in all 3 years. The species composition of the bumblebee communities estimated from UHCs on flowers were also similar to those actually observed. There was a significant positive correlation between the observed number of visits by each of three bumblebee species (contributing 3-68% of flower visits) and the estimated number of visits based on UHC profiles. Furthermore, significant correlations were obtained separately for workers and drones of two of the study species. Seed set of comfrey plants was positively correlated to overall bumblebee visitation and the total amount of UHCs on flowers, suggesting the potential for pollen limitation. We suggest that quantifying cumulative footprint hydrocarbons provides a novel way to assess floral visitation by insects and can be used to predict seed set in pollen-limited plants.     

Evolution of mutualism in plant-pollinator interactions on islands

The evolution and ecology of interactions between plants and pollinators are discussed based on the studies on the Izu Islands and mainland Honshu, Japan. The species assemblage is depauperate, and long-tongued pollinators are absent or rare on the islands. Bumblebees, one of the most important pollinators in Japan, are generally absent. Plants depending strongly on bumblebee pollination are absent on Izu Islands, but those depending on varied pollinators including bumblebees display smaller flower sizes and accommodate smaller pollinators than their mainland counterparts. Breeding systems of these species also shift to partial inbreeding, possibly an evolutionary result of the decrease in pollinator availability. Changes in flowering phenology between mainland and island populations also occur. Plants in the islands tend to reproduce vegetatively less frequently and produce greater numbers of smaller seeds than those in the mainland. The possibility of evolution on the side of island pollinator species is also discussed, although there are few data on this topic.     

Climatic niche breadth determines the response of bumblebees (<Emphasis Type="Italic">Bombus</Emphasis> spp.) to climate warming in mountain areas of the Northern Iberian Peninsula

Studies examining species range shifts in the face of climate change have consistently found that response patterns are complex and varied, suggesting that ecological traits might be affecting species response. However, knowledge of how the traits of a species determine its response to climate change is still poorly understood. Here we investigate the role of species-specific climate niche breadth in forecasting bumblebee (Bombus spp.) responses to regional climate warming in the Cantabrian Range (north-western Iberian Peninsula). Climate niche breadth was defined using known data for occurrences of specific species at their continental (i.e., European) scale of distribution. For each bumblebee species, climate niche breadth was found to be related to (1) the elevational range shifts of species between their historical (1988–1989) and recent (2007–2009) distribution and (2) the variation in the climatic conditions of the localities they inhabited (i.e., the local climate space) between both study periods. Our results show a strong relationship between climate niche breadth, particularly thermal niche breadth, and the response of bumblebee species to climate warming, but only when this response was determined as variations in local climate space. The main conclusions of our work are thus twofold. First, variations in the climatic conditions underlying range shifts are useful in making accurate assessments of the impact of climate change on species distributions. Second, climate niche breadth is a particularly informative ecological trait for forecasting variations in species responses to climate change.     

Changes in the species composition of a Karoo avifauna over time: a case study from Deelfontein,South Africa

A collection of almost 830 specimens of birds and their eggs was made at Deelfontein, Northern Cape province, South Africa, in 1901 and 1902, by two soldiers who had enlisted in the Yeomanry during the South African (Boer) War. A total of 151 bird species has been recorded in the Deelfontein area in two periods, 1901–1902 and 1987–1992. There has been no apparent change in occurrence in 82 species, but 40 species were recorded only in 1901–1902, and 29 species were recorded only by observers who completed field cards for the area for the SABAP surveys in 1987–1992. It is suggested that the differences in bird species composition are most likely associated with anthropogenic influences including land-use changes and over-utilisation of shrublands as grazing for domestic livestock.     

Foraging habitats and foraging distances of bumblebees, Bombus spp. (Hym., Apidae), in an agricultural landscape

Abstract: In selected foraging habitats of an agricultural landscape flower visits of bumblebees and community structure of foraging bumblebees were studied, with special regard to the role of crops as super-abundant resources. Most crops represent temporal foraging habitats with high abundance of bumblebees but mainly with low diversity in the bumblebee forage community, in contrast to permanent foraging habitats such as, for example, a hedgerow. The high numbers of bumblebees in the monoculture of crop plantations consisted mainly of short-tongued bumblebee species. The role of foraging distances for the visitation rate of foraging habitats was studied by performing capture–recapture experiments with natural nests of Bombus terrestris , Bombus lapidarius and Bombus muscorum . Differences were found on the species as well as the individual level. The foraging distances of B. muscorum were more restricted to the neighbourhood of the nesting habitat than the foraging activity of B. terrestris and B. lapidarius . High percentages of B. terrestris workers were recaptured while foraging on super-abundant resources in distances up to 1750 m from the nest. Isolated patches of highly rewarding forage crops, in agricultural landscapes, are probably only accessed by bumblebee species with large mean foraging distances, such as the short-tongued B. terrestris . Species like the rare, long-tongued B. muscorum depend on a close connection between nesting and foraging habitat. A restricted foraging radius might be one important factor of bumblebee species loss and potential pollinator limitation in modern agricultural landscapes. Furthermore, long-distance flights of bumblebee pollinators have to be considered in the present discussion on gene flow from transgenic plant species on a landscape scale.