黄金肥蛛体内Wolbachia的感染检测及wsp基因序列分析

细胞质共生细菌Wolbachia能引起节肢动物的胞质不亲和、孤雌生殖、遗传雄性的雌性化和杀雄等。本研究采用Wolbachia的wsp基因的通用引物,通过PCR扩增法检测了7种蜘蛛体内Wolbachia的感染情况,发现在黄金肥蛛体内存在Wolbachia感染。对黄金肥蛛体内的wsp基因进行了克隆与测序,并利用所测序列与其他已发表的wsp基因序列建立系统树,结果表明其体内Wolbachia属于A大组．     

昆虫共生细菌Wolbachia的研究进展

Wolbachia是广泛分布在节肢动物生殖组织的一类细胞质遗传的细菌,它们能通过多种机制调节寄生的生殖,包括诱导细胞质不亲和,孤雌生殖和遗传上的雄性雌性化,目前对这些微生物的研究已取了可喜的进展,通过主要综述Wolbachia的分布,功能,系统发育,多样性及时空动态,也讨论了将来的研究方向     

寄生蜂体内共生菌Wolbachia研究进展

Wolbachia是广泛分布在节肢动物生殖组织中的细胞质遗传细菌,在寄生蜂中可以通过诱导胞质不亲和、孤雌生殖、雄性雌性化和杀雄等多种方式调节寄主的生殖.本文在综述了寄生蜂体内共生菌Wolbachia的类群和分化、传播方式及其对寄主生物学特性的影响、温度通过对Wolbachia的作用而影响寄生蜂的表现等基础上,讨论了如何...     

共生菌Wolbachia引起宿主细胞质不亲和的研究进展

Wolbachia 是一类广泛存在于节肢动物以及线虫体内细胞质中呈母系遗传的共生细菌,能够在宿主中产生细胞质不亲和、孤雌生殖、雌性化及杀雄等多种生殖调控作用,其中细胞质不亲和是指被 Wolbachia 感染的雄性个体与未感染的雌性个体（单向不亲和）,或者感染不同株系 Wolbachia 的雌性个体（双向不亲和）交配后不能或很少产生后代,或者后代偏雄性的现象。细胞质不亲和作用使感染的雌性个体在种群中具有很大的生殖优势,凭借这种生殖优势,Wolbachia 能够迅速在宿主种群中扩张。细胞质不亲和的机理探索主要集中在细胞学水平上,其中广为接受的精子“修饰”和“拯救”理论认为,精巢中的 Wolbachia 能够修饰宿主的精细胞,使其不能和卵细胞正常融合,但是当母本感染相同的 Wolbachia 时,就能够将“修饰”过的精子细胞“拯救”过来,使其恢复与卵细胞的正常融合。而分子机理上的探索也开始在转录组、基因组和miRNA水平上对部分昆虫展开了研究。影响细胞质不亲和的因素有很多,包括宿主遗传背景、 Wolbachia 株系、Wolbachia 基因型、共生菌密度（浓度、滴度）、雄虫年龄、环境因素以及共生菌在宿主生殖组织的分布等。近年来,人类也应用细胞质不亲和控制害虫（主要是蚊虫）和人类疾病,取得了较好的进展。     

沃尔巴克氏体Wolbachia对宿主的生殖调控作用及其研究进展

沃尔巴克氏体Wolbachia是广泛分布于节肢动物体内的共生微生物,可通过宿主卵的细胞质传递给子代。Wolbachia通过多种方式调控其宿主的生殖活动,包括细胞质不亲和、孤雌生殖、雌性化、杀雄性和增强雄性或雌性的生殖力。通过这些调控作用促进其在宿主种群内的广泛传播。文章简要综述Wolbachia对宿主的生殖调控作用、水平传播、Wolbachia基因和应用方面的研究。     

欧洲熊蜂Bombus terretris入侵研究进展

欧洲熊蜂Bombus terrestris被出口到自然分布区外为作物传粉,现已在澳大利亚、新西兰、日本、以色列、智利和阿根廷等国家建立野生种群.欧洲熊蜂与本土传粉生物竞争蜜粉源植物,传播病虫害,与本土熊蜂杂交产生不育子代.欧洲熊蜂入侵可能引起本地传粉昆虫牛物多样性降低,危害生态系统传粉功能的安全.中国从1998年开始引入欧洲熊蜂为大棚作物传粉,但日前尚无欧洲熊蜂入侵我国的报道.中国是熊蜂生物多样性最丰富的国家之一,具有欧洲熊蜂适生环境,欧洲熊蜂有可能入侵我国.防止欧洲熊蜂入侵最重要和最有效的办法是减少进口该物种和进行科学的放蜂管理.     

火红熊蜂微卫星标记的筛选及种特异性分析

火红熊蜂Bombus pyrosoma是中国特有的熊蜂资源, 在华北地区分布十分丰富, 是众多野生植物和农作物的重要传粉者。为了探究火红熊蜂的遗传结构及其进化关系, 首次开展了该种熊蜂卫星标记的筛选及其种特异性研究。本研究采用生物素-磁珠吸附分离法从火红熊蜂基因组中筛选微卫星标记, 并选取黑熊蜂亚属Melanobombus其他7种熊蜂进行了这些标记的种特异性验证。结果表明： 不同探针与磁珠杂交产生的微卫星标记阳性克隆率存在很大差异, TC探针的微卫星阳性克隆率最高为82%; TG探针次之, 为28%; AT和GC探针分离未获得微卫星标记克隆。根据获得的阳性克隆的序列设计引物进行筛选验证, 共获得31对熊蜂微卫星序列特异性引物。微卫星标记分析发现, 完美型(perfect)18个, 占58.1%; 非完美型(imperfect)10个, 占32.3%; 混合完美型(compound perfect)1个, 占3.2%; 混合非完美型(compound imperfect)2个, 占6.4%。不同探针的微卫星核心序列重复数不同, TC探针和TG探针的微卫星核心序列最高重复数分别为28和15个, 最低重复数分别为7和11个。利用所获得的31对微卫星引物对黑熊蜂亚属其他7种熊蜂进行检测, 有26对引物可以扩增所测试的7种熊蜂, 其他5对引物只能扩增部分熊蜂种类, 其中BPM5是火红熊蜂种特异性引物。本研究从火红熊蜂基因组中筛选的微卫星标记, 不仅可用于火红熊蜂的遗传结构、 分子进化和资源保护等方面的研究, 而且可进一步用于黑熊蜂亚属其他种群的遗传特性分析。     

华北地区六种熊蜂的地理分布及生态习性

2005～2007年连续3年对华北地区小峰熊蜂Bombus hypocrita、密林熊蜂B.patagiatus、红光熊蜂B.ignitus、明亮熊蜂B.lucorum、火红熊蜂B.pyrosoma和重黄熊蜂B.picipes等6种熊蜂的地理分布和生态习性进行研究。结果表明,这6种熊蜂在华北地区的地理分布差异很大,火红熊蜂分布最广,重黄熊蜂分布最窄。6种熊蜂在垂直分布上也存在差异,红光熊蜂分布于较低海拔高度地区,明亮熊蜂分布于较高海拔高度地区,但在海拔1300～1800m范围内6种熊蜂都有分布。6种熊蜂中,火红熊蜂的年活动周期较长,为180天左右。小峰熊蜂、明亮熊蜂、密林熊蜂和重黄熊蜂的年活动周期居中。红光熊蜂的年活动周期最短,为140天左右。6种熊蜂采访植物涉及到17科63种,采访植物存在一定的偏好性,主要采访豆科、菊科、蔷薇科和唇形科等植物;而且,不同种熊蜂采集植物的种类也存在较大差异。     

熊蜂主要病虫害的发生和危害现状

熊蜂以其独有的形态特征与生物学特性,在植物授粉中发挥着十分重要作用.然而受寄生虫、真菌等多种病原体影响,近几十年来全球多个地区熊蜂多样性急剧下降.欧洲地熊蜂Bombus terrestris在全球商业化推广应用,加剧了相关熊蜂病虫害的传播和蔓延,已在多地造成生物入侵危害,导致当地传粉蜂多样性下降.本文综述了熊蜂主要病虫害的种类、危害和传播情况,以期有全面深入的认识,并提出对进口商业化熊蜂的管理措施,为我国本土熊蜂资源保护研究奠定基础.     

草乌花蜜产量的梯度分布及熊蜂自下而上的访花行为

收益降低假说(declining reward hypothesis)认为熊蜂自下而上的访花顺序是对花蜜产量的直接响应,先访问下部花蜜产量高的花可以获得更多的收益;花开口方向假说认为自下而上访花是因为熊蜂更容易看见其上部的花朵。为了验证上述两个假说,我们于2008年8月在北京小龙门国家森林公园调查了红光熊蜂(Bombus ignitus)访问草乌(Aconitum kusnezoffii)直立和倒立顶生花序的访问顺序,测量了直立花序下部雌性阶段花和上部雄性阶段花花蜜的糖浓度、体积,计算了花蜜中的糖含量。结果表明,红光熊蜂在直立花序和倒立花序内均以向上运动为主,分别占总运动次数的62.77%和68.35%;直立花序下部雌性阶段花花蜜糖浓度比上部雄性阶段花低1.44%,但是花蜜体积和花蜜中的糖含量都显著高于雄性阶段的花。由于熊蜂访问倒立花序时先访问的是下部的低回报雄性阶段的花,然后再访问上部高回报的雌性阶段的花,这与收益降低假说矛盾,表明红光熊蜂自下而上访问草乌直立花序可能不是受到花蜜产量的调节。     

Interspecific geographic distribution and variation of the pathogens Nosema bombi and Crithidia species in United States bumble bee populations

Several bumble bee (Bombus) species in North America have undergone range reductions and rapid declines in relative abundance. Pathogens have been suggested as causal factors, however, baseline data on pathogen distributions in a large number of bumble bee species have not been available to test this hypothesis. In a nationwide survey of the US, nearly 10,000 specimens of 36 bumble bee species collected at 284 sites were evaluated for the presence and prevalence of two known Bombus pathogens, the microsporidium Nosema bombi and trypanosomes in the genus Crithidia. Prevalence of Crithidia was ≤10% for all host species examined but was recorded from 21% of surveyed sites. Crithidia was isolated from 15 of the 36 Bombus species screened, and were most commonly recovered from Bombus bifarius, Bombus bimaculatus, Bombus impatiens and Bombus mixtus. Nosema bombi was isolated from 22 of the 36 US Bombus species collected. Only one species with more than 50 sampled bees, Bombus appositus, was free of the pathogen; whereas, prevalence was highest in Bombus occidentalis and Bombus pensylvanicus, two species that are reportedly undergoing population declines in North America. A variant of a tetranucleotide repeat in the internal transcribed spacer (ITS) of the N. bombi rRNA gene, thus far not reported from European isolates, was isolated from ten US Bombus hosts, appearing in varying ratios in different host species. Given the genetic similarity of the rRNA gene of N. bombi sampled in Europe and North America to date, the presence of a unique isolate in US bumble could reveal one or more native North American strains and indicate that N. bombi is enzootic across the Holarctic Region, exhibiting some genetic isolation.     

Displacement of a native by an alien bumblebee: lower pollinator efficiency overcome by overwhelmingly higher visitation frequency

Biological invasions might constitute a major threat to mutualisms. Introduced pollinators might competitively displace their native counterparts, which in turn affects the pollination of native plants, if native and alien visitors differ in pollinator effectiveness. Since its invasion in 1994 into south-west Argentina, the introduced European bumblebee Bombus ruderatus has continuously increased in abundance, along with a simultaneous decrease in the abundance of the native Bombus dahlbomii. The latter is the only native bumblebee species of the temperate forests of southern South America, and the main pollinator of the endemic herb Alstroemeria aurea. In order to evaluate the impact of the ongoing displacement of the native by the alien bumblebee, we compared the pollinator effectiveness (i.e., the combination of pollinator efficiency per visit and visitation frequency) between both bumblebee species, as well as related pollinator traits that might account for potential differences in pollinator efficiency. Native Bombus dahlbomii, which has a larger body and spent more time per flower, was the more efficient pollinator compared to Bombus ruderatus, both in terms of quantity and quality of pollen deposited per visit. However, Bombus ruderatus was a much more frequent flower visitor than Bombus dahlbomii. As a consequence, Bombus ruderatus is nowadays a more effective pollinator of A. aurea than its native congener. Despite the lack of evidence of an increase in seed set at the population level, comparisons with historical records of Bombus dahlbomii abundances prior to Bombus ruderatus' invasion suggest that the overall pollination intensity of A. aurea might in fact have risen as a consequence of this invasion. Field experiments like these, that incorporate the natural variation in abundance of native and alien species, are powerful means to demonstrate that the consequences of invasions are more complex than previous manipulated and controlled experiments have suggested.     

Functional morphology of the visual system and mating strategies in bumblebees (Hymenoptera,Apidae, Bombus)

Bumblebee mating behaviour intrigued Darwin over 150 years ago and has elicited much interest since. Despite our increasing knowledge about male mating strategies, we still know little about the signals and cues involved, the sender‐receiver relationship and the functional adaptations of the involved sensory systems. Although several authors have noticed a close relationship between the mating system and male‐specific elaboration of the visual system, studies on the functional adaptations have yet to be conducted. We investigated the functional morphology of the compound eyes in 11 species of Bombus from various subgenera in detail. Of these, four species (Bombus confusus, Bombus melaleucus, Bombus mendax, Bombus niveatus) have enlarged male eyes, characterized by a higher number of ommatidia compared with worker eyes and a frontal zone with enlarged facets, which is likely to be associated with improved spatial resolution and contrast sensitivity. In these species, perching mating strategies are found. In contrast, males of species that patrol scent routes (Bombus hortorum, Bombus lapidarius, Bombus pascuorum, Bombus pratorum, Bombus soroeensis, Bombus terrestris, Bombus wurflenii) show no distinct eye adaptations, and their eye morphology closely resembles that of the workers. A phylogenetic analysis of male eye structure indicates that enlarged males eyes may have been the ancestral state in Bombus. © 2014 The Linnean Society of London     

Phylogenetic relationships among bumble bees (Bombus Latr.): a reappraisal of morphological evidence

Abstract. Cladistic analyses of morphological characters of adult bumble bees show significantly higher congruence among characters of the male genitalia than among other characters of males and females. Phylogenetic interpretations of groups supported by the combined morphological evidence (even with minimal assumptions) include (1) that the earliest diverging species belong to the para-phyletic subgenus Mendacibombus , together with Bombus nevadensis and B.confusus ; (2) that, in contrast, species of the subgenus Bombus (sensu stricto) share a relatively recent common ancestor with B.pressus and B.rufipes ; and (3) that Psithyrus (the social parasites) is a monophyletic group, and the sister-group of B.persicus. For genus-group nomenclature a single genus Bombus (sensu lato) is recommended, to include Psithyrus as another subgenus. Names for sections and for groups of subgenera are synonymized with subgeneric names.     

Cytological variation and pathogenicity of the bumble bee parasite Nosema bombi (Microspora, Nosematidae)

In three field seasons, 2003-2005, bumble bees were collected in southern Sweden and eastern Denmark in search of microsporidian parasites. Of the 16 bumble bee species studied, microsporidia were found in Bombus hortorum, Bombus hypnorum, Bombus lapidarius, Bombus lucorum, Bombus pascuorum, Bombus pratorum, Bombus ruderarius, Bombus subterraneus and Bombus terrestris. Only one microsporidian species, Nosema bombi, was recorded. A microsporidium found in B. pratorum differed cytologically from microsporidia of the other host species. In the most frequently infected host, B. terrestris, the prevalence was 20.6%. Totally 1049 specimens were dissected. The light microscopic and ultrastructural cytology and pathology of N. bombi is described with focus on the variation recorded. Variation was especially prominent in the shape, size and coupling of spores, and in the length and arrangement of the polar filament. In four host species microsporidian infection was restricted to peripheral fat cells.     

Absolute configuration of chiral terpenes in marking pheromones of bumblebees and cuckoo bumblebees

The absolute configurations of citronellol, 2,3-dihydrofarnesol, and 2,3-dihydrofarnesal in male marking pheromones of seven species of bumblebees and cuckoo bumblebees were determined by enantioselective gas chromatography on a capillary column coated with 60% heptakis(2,3-di-O-acetyl-6-O-TBDMS)-beta-cyclodextrin in polysiloxane PS 268. Pure (-)-S-enantiomers of all three terpenes were found in the labial glands of all investigated specimens of the following species: Bombus (Bombus) terrestris, B. (Bombus) lucorum, B. (Pyrobombus) pratorum, B. (Pyrobombus) pyrenaeus, B. (Pyrobombus) jonellus, B. (Pyrobombus) impatiens, and the cuckoo bumblebee B. (Ashtonipsithyrus) bohemicus. Within species, specimens were collected at different localities and in different years. Except for 2,3-dihydrofarnesol in B. terrestris, this is the first report on the absolute configuration of terpenes in marking pheromones of bumblebees.     

Novel microsatellite DNA loci for Bombus terrestris (Linnaeus, 1758)

We present details and characteristics of 123 novel polymorphic microsatellite DNA loci for Bombus terrestris. Thirty-four of these loci have been tested in nine other Bombus species and 25 of them showed polymorphisms in at least one species. These microsatellite DNA loci together with the already established 60 loci will be useful for characterizing wild and managed populations of B. terrestris and other Bombus species as well as for detailed genetic studies in including mapping studies and genome annotations.     

Bumblebees experience landscapes at different spatial scales: possible implications for coexistence

Coexistence in bumblebee communities has largely been investigated at local spatial scales. However, local resource partitioning does not fully explain the species diversity of bumblebee communities. Theoretical studies provide new evidence that partitioning of space can promote species coexistence, when species interact with their environment at different spatial scales. If bumblebee species possess specific foraging ranges, different spatial resource utilisation patterns might operate as an additional mechanism of coexistence in bumblebee communities. We investigated the effects of the landscape-wide availability of different resources (mass flowering crops and semi-natural habitats) on the local densities of four bumblebee species at 12 spatial scales (landscape sectors with 250–3,000 m radius) to indirectly identify the spatial scales at which the bumblebees perceive their environment. The densities of all bumblebee species were enhanced in landscapes with high proportions of mass flowering crops (mainly oilseed rape). We found the strongest effects for Bombus terrestris agg. and Bombus lapidarius at large spatial scales, implying foraging distances of 3,000 and 2,750 m, respectively. The densities of Bombus pascuorum were most strongly influenced at a medium spatial scale (1,000 m), and of Bombus pratorum (with marginal significance) at a small spatial scale (250 m). The estimated foraging ranges tended to be related to body and colony sizes, indicating that larger species travel over larger distances than smaller species, presumably enabling them to build up larger colonies through a better exploitation of food resources. We conclude that coexistence in bumblebee communities could potentially be mediated by species-specific differences in the spatial resource utilisation patterns, which should be considered in conservation schemes.     

Forward to the north: two Euro-Mediterranean bumblebee species now cross the Arctic Circle

In recent decades, several animal and plant species have been in regression (population size decrease and geographical distribution shrinking). This loss of biodiversity can be due to various factors such as the destruction and fragmentation of habitat, urban development, pesticides or climate change. However, some species benefit from these changes and expand their distribution. Here we report observations (in 2013 and 2014) of two Euro-Mediterranean bumblebee species: Bombus terrestris for the first time and Bombus lapidarius, north of the Arctic Circle in Fennoscandia.     

Proboscis length and resource utilization in two Uruguayan bumblebees: Bombus atratus Franklin and Bombus bellicosus Smith (Hymenoptera: Apidae)

Bumblebees (Bombus sp.) are eusocial insects with an annual life cycle whose use as pollinator of crops has gained great importance in modern agriculture. Several authors have found that resource use in Bombus species is usually based on the correlation between the proboscis length of the bumblebees and the corolla depth of the flowers. The aim of this study was to determine proboscis length of Bombus atratus and B. bellicosus, two Uruguayan bumblebees, and verify the resource exploitation testing two cultivated species, the red clover and the bird's foot trefoil. Bumblebee foraging activity was recorded in two culture conditions: in a red clover and bird's foot trefoil mixed meadow, and in contiguous plots of these legumes, and the proboscis length of collected foragers was determined. Both species of bumblebees exploited red clover and bird's foot trefoil although they did it in different proportions in all instances tested. The results indicated that the choice of the resources in B. atratus and B. bellicosus was influenced by their proboscis length. Bombus atratus has a longer proboscis and preferably visited red clover, possibly obtaining nectar easier and faster than B. bellicosus, which has a shorter proboscis. Bombus bellicosus used both resources without any clear preference.