油茶地蜂生活史及相关生物学习性

油茶地蜂Andrena camellia Wu 是江西、湖南等地油茶花期主要传粉昆虫之一。2006–2007年在江西宜春对油茶地蜂除成虫外各虫态的形态特征、生活史及幼虫和成虫的行为等生物学特性进行了观察研究。结果表明： 该蜂在江西宜春1年发生1代。成虫10月中旬开始出巢活动, 雄蜂早于雌蜂3 d左右出现,完成交尾后数日死亡,雄蜂出巢后寿命18 d左右,雌蜂约38 d。卵期约8 d。幼虫期24 d左右,幼虫取食完花粉球后长成老熟幼虫进入滞育期,滞育期约241 d。翌年9月中旬开始化蛹,蛹期约30 d。出土后的雌蜂当天就可以交配,交配后的雌蜂在羽化地点附近选址筑巢,采集油茶的花粉和花蜜于虫室中制成球形蜂粮并在上面产卵,每粒花粉球上产卵一枚。     

缘叶舌蜂与其天敌窄头褶翅蜂的生物学特性 及其与环境变量的相关性

【目的】记录亚热带地区独栖性膜翅目昆虫的生物学特性,研究乔木树种多样性对缘叶舌蜂Hylaeus perforata及其天敌窄头褶翅蜂Gasteruption corniculigerum的影响。【方法】2015年8月至2018年9月,在江西省德兴市新岗山镇的生物多样性与生态系统服务功能实验样地人工林设置了标准化的人工巢管收集缘叶舌蜂与窄头褶翅蜂,观察其生物学特性,分析缘叶舌蜂和天敌窄头褶翅蜂多度以及窄头褶翅蜂寄生率与乔木树种丰富度、海拔、坡度、北向指数和东向指数5个环境变量的相关性。【结果】缘叶舌蜂一年多代,每年5-9月筑巢,4-8月羽化活动;使用树脂筑巢;平均每次建造巢室3.75±2.24个;巢的平均直径4.73±1.31 mm;以末龄幼虫越冬;后代性比显著偏向雌性。窄头褶翅蜂营盗寄生;每年仅在7月寄生缘叶舌蜂,后代会消耗掉寄主巢内所有蜂粮;9月羽化活动;羽化时间远晚于同期的寄主缘叶舌蜂。缘叶舌蜂和窄头褶翅蜂的多度与树种丰富度呈正相关,而其他4个环境变量对缘叶舌蜂和窄头褶翅蜂的多度没有显著影响。【结论】缘叶舌蜂是典型的独栖性蜜蜂,每次筑巢会产下多个后代,在春夏及初秋活动;窄头褶翅蜂在夏季寄生缘叶舌蜂,秋季羽化活动,发育时间远长于寄主,其他盗寄生类群一般寄生单个寄主的巢室,而窄头褶翅蜂会将寄主的所有巢室破坏并消耗掉寄主储存的所有蜂粮;树种多样性更高的环境更有利于高营养级的物种生存。     

寄主龄期、过寄生和寄主饥饿处理对菜蛾盘绒茧蜂幼蜂及畸形细胞发育的影响

过寄生、寄生时寄主龄期和寄生后寄主饥饿处理影响菜蛾盘绒茧蜂Cotesia plutellae（Kurdj.）幼蜂及畸形细胞的发育。显微解剖和观察表明,4龄小菜蛾Plutella xylostella L.幼虫被寄生后,其体内菜蛾盘绒茧蜂幼蜂发育不整齐、假寄生比例增高。过寄生后,每头被寄生的寄主血腔中畸形细胞数量明显增多,但直径变小;随着过寄生程度的加剧,幼蜂发育严重受阻。寄主营养显著影响体内幼蜂及畸形细胞的发育,被寄生的小菜蛾经饥饿处理62 h后,体内畸形细胞的数量、活性明显降低,与此同时,幼蜂的发育也受到明显抑制,寄主发育与寄生蜂和畸形细胞的发育呈正相关性。由此可见,寄主不同龄期、过寄生及寄主营养状况均对寄主体内幼蜂和畸形细胞发育产生影响。     

三种稻田常见螯蜂对半翅目害虫的寄主偏好性及控害作用

【目的】探明两色食虱螯蜂Echthrodelphax fairchildii、黄腿双距螯蜂Gonatopus flavifemur和稻虱红单节螯蜂Haplogonatopus apicalis 3种稻田常见螯蜂对半翅目害虫的寄主偏好性及控害作用。【方法】在非选择条件下,分别以褐飞虱Nilaparvata lugens、白背飞虱Sogatella furcifera、灰飞虱Laodelphax striatellus、黑尾叶蝉Nephotettix cincticeps和伪褐飞虱Nilaparvata muiri为寄主,观察两色食虱螯蜂、黄腿双距螯蜂和稻虱红单节螯蜂的取食、寄生以及子代生长发育情况;并在选择条件下观察3种螯蜂对稻飞虱的寄主选择性,评价螯蜂的寄主偏好性。根据以上试验,评出3种螯蜂各自的适宜寄主;并选择适宜寄主测定3种螯蜂的寿命、取食量和寄生量,评价其控害作用。【结果】两色食虱螯蜂可取食和寄生褐飞虱、灰飞虱、白背飞虱和伪褐飞虱,以前3种为两色食虱螯蜂的适宜寄主,伪褐飞虱次之;黑尾叶蝉为其非取食、寄生寄主。黄腿双距螯蜂可取食和寄生4种飞虱：褐飞虱和灰飞虱适合性较高,白背飞虱次之,伪褐飞虱最差。黑尾叶蝉可为黄腿双距螯蜂的取食寄主,但非寄生寄主。稻虱红单节螯蜂以白背飞虱为最适寄主,灰飞虱次之;其他3种寄主仅能被稻虱红单节螯蜂取食,不能被成功寄生。在适宜寄主上,稻虱红单节螯蜂雌虫的寿命、总取食和寄生合计量均最高,两色食虱螯蜂的最低,黄腿双距螯蜂的居中;3种螯蜂日均取食量和寄生量的消长动态波动幅度不大。【结论】两色食虱螯蜂偏好寄生褐飞虱、灰飞虱和白背飞虱,控害作用相对最弱;黄腿双距螯蜂偏好寄生褐飞虱和灰飞虱,控害作用居中;稻虱红单节螯蜂偏好寄生白背飞虱,控害作用最强。     

可疑柄瘤蚜茧蜂对高温下不同龄期黑豆蚜的寄生及其适合度表现

研究寄生蜂对寄主不同龄期的寄生策略通常采用适温下（≈25℃）培养的寄主进行试验。 为探究蚜茧蜂对高温下生长的寄主蚜虫的寄生反应及其适合度表现,在30℃条件下饲养寄主孤雌胎生无翅黑豆蚜Aphis fabae Scopli,获得不同龄期若蚜和刚羽化的成蚜,分别提供给可疑柄瘤蚜茧蜂Lysiphlebus ambiguous Haliday寄生,观察蚜茧蜂的寄生率以及后代性比、体型大小和发育时间等适合度相关特性。结果表明： 可疑柄瘤蚜茧蜂对1至4龄若蚜及成蚜均寄生,但偏向寄生较早龄期的若蚜,对成蚜的寄生率为28.0％,显著低于对1龄（400％）和2龄（42.8%）寄主若蚜的寄生率。后代雌蜂比例和体型随寄主龄期（体型）增大而减小,而发育历期则呈现“中间低,两头高”的格局。后代性比、体型大小及发育历期等适合度表现与此前适温（≈25℃）下得到的结果截然相反。因此推测,寄主黑豆蚜体型或龄期可能不是或不全部是可疑柄瘤蚜茧蜂评价寄主质量的依据,其他与寄主蚜虫内共生菌动态相关的线索（如行为的,化学的等）可能才是其评价寄主质量的依据。     

滇东南岩溶地貌下土壤物理性质对油茶地蜂种群数量的影响

【目的】揭示滇东南岩溶地貌下土壤物理性质对油茶地蜂Andrena camellia Wu种群数量的影响。【方法】测定并比较江西宜春丘陵地貌下具油茶地蜂"筑巢适生区"和无"筑巢适生区"的油茶林地,以及云南文山岩溶地貌下"峰丛"和"洼地"中油茶林地的土壤硬度值、容重、含水量、温度和颗粒组成,并测定四类型样地中油茶地蜂巢穴密度和访花多度。【结果】滇东南岩溶地貌中峰丛和洼地样地土壤硬度、容重和温度显著高于江西宜春具"筑巢适应区"样地,但土壤含水量显著低于江西宜春具"筑巢适应区"样地。未检测到不同林地间土壤颗粒组成百分率差异。滇东南岩溶地貌中峰丛和洼地样地油茶地蜂巢穴密度和访花多度显著低于江西宜春具"筑巢适生区"的样地。土壤物理性质影响油茶地蜂巢穴密度。土壤硬度可作为重要指标,用于快速、简便检测油茶林下土壤是否适应油茶地蜂筑巢。滇东南油茶样地土壤硬度系统测定结果表明,岩溶地貌典型样地土壤硬度高于适应油茶地蜂筑巢的土壤硬度阀值(2.50 MPa)。【结论】滇东南岩溶地貌下油茶林地土壤物理性质不适应油茶地蜂筑巢。     

螟蛉盘绒茧蜂的过寄生行为及其对子代生长发育的影响

【目的】过寄生现象普遍存在于寄生蜂寄生过程中。本研究旨在探究螟蛉盘绒茧蜂Cotesia ruficrus的过寄生对子代发育的影响及影响过寄生行为的主要因素。【方法】室内研究了螟蛉盘绒茧蜂在其寄主稻纵卷叶螟Cnaphalocrocis medinalis3龄幼虫上过寄生行为的发生,不同产卵次数对寄主存活及子代蜂生长发育的影响,研究了不同接蜂时间和不同接蜂密度对过寄生发生的影响。【结果】螟蛉盘绒茧蜂存在过寄生行为,无论雌蜂有无产卵寄生经历,均能在被自身寄生过和同种不同个体寄生过的寄主内产卵。寄生蜂茧量随着被产卵次数的增加而增加,被产卵3~5次的寄主体内死亡的寄生蜂幼虫数随着增大。寄主在育出蜂前的死亡率随着被产卵寄生次数的增加而增加,被产卵5次时,寄主育出蜂前死亡率达50%。过寄生使螟蛉盘绒茧蜂子代蜂卵-蛹的历期延长,羽化率和雌雄性比下降,雌蜂体型随寄生次数的增加显著变小。过寄生率随着接蜂密度及接蜂时间的增加而增加。【结论】在寄主上产卵2次对螟蛉盘绒茧蜂子代发育是最适合的,产卵3次及以上为过寄生。过寄生使蜂子代发育适合度降低,不利于子代生长发育。在室内大量繁殖螟蛉盘绒茧蜂时,应减少接蜂密度和接蜂时间,从而减少过寄生的发生。     

斑痣悬茧蜂的寄主种间选择性及其子代蜂发育适合度表现

为检验基于经典搜寻理论的最优膳食模型的预测——产卵雌蜂应该选择最适于子代蜂发育的寄主种进行产卵,本研究以斑痣悬茧蜂(Meteorus pulchricornis)及其寄主斜纹夜蛾(Spodoptera litura)和粘虫(Mythimna separata)的幼虫为材料,在控制寄主体型大小和龄期影响的基础上,分别在体型大小相近和日龄相同的3个水平上观察了斑痣悬茧蜂对2种寄主幼虫的选择偏好,并观察了子代蜂生长发育适应度表现。在观察期(1h)内,当2种寄主幼虫的体型相近或者龄期相同的情况下,斑痣悬茧蜂对粘虫的产卵器刺扎次数以及寄生率(用结茧率表示)均高于斜纹夜蛾;而在斜纹夜蛾幼虫体内发育出的子代蜂茧重和体型均大于粘虫,成蜂寿命无显著差异。最后,对斑痣悬茧蜂的寄主选择和子代发育表现不一致现象进行了讨论。     

中国小彩带蜂族的研究及艳小彩带蜂属一新种记述(膜翅目:蜜蜂总科:隧蜂科)

本文两作者在研究苏联科学院动物所及中国科学院动物所939个标本的基础上记述中国小彩带蜂族Nomioidini 7个种,其中海南艳小彩带蜂Ceylalictus(Alronomiaides)hainanicus为新种。     

斑痣悬茧蜂对斜纹夜蛾不同虫龄幼虫的选择及后代发育表现

为探究容性寄生蜂对不同龄期寄主幼虫的选择性及其子代蜂发育表现的关联,通过双选试验观察了斑痣悬茧蜂(Meteorus pulchricornis)对斜纹夜蛾(Spodoptera litura)不同虫龄幼虫的寄生选择,并观察了与子代蜂适合度相关的特性表现.结果表明:斑痣悬茧蜂在4龄与5龄之间未表现出偏好,在2龄和3龄、3龄和4龄之间显著偏好较低虫龄;结茧率在不同寄主虫龄间无显著差异,羽化率随寄主虫龄增大而减小,寄生2、3龄幼虫的子代蜂显著高于寄生5龄;寄生5龄幼虫的子代蜂死亡率比寄生2龄的高2.5倍,比寄生3龄的高5.4倍.寄生3龄幼虫的子代蜂发育历期最短(11.9 d),比寄生4龄幼虫的短6.8 d,比寄生2龄幼虫的短4.7 d;子代蜂体型大小在寄生的寄主虫龄间无显著差异.根据研究结果推测,斑痣悬茧蜂在寄生时可能不是根据寄主龄期来评价寄主品质,而是基于寄主体型大小进行评价.     

Records of bees (Hymenoptera: Apoidea) new to both Georgia and Transcaucasia revealed by DNA barcoding

Community composition of local pollinator assemblages, population dynamics and distribution patterns of many species are still poorly known, especially in little studied regions like Transcaucasia. We generated a total of 189 DNA barcodes from bees collected in 14 apple orchards in central and eastern Georgia to extend our knowledge of their distribution. Sequences (ca. 700 bp of the mitochondrial cytochrome oxidase I gene) were compared to the NCBI nucleotide database. Using a threshold of 98% similarity, analyses suggested that the sampled bees belong to 36 species of Apidae, Andrenidae, Halictidae, and Megachilidae. We report five bee species for the first time for Georgia: Andrena alfkenella Perkins, 1914, Halictus cochlearitarsis Dours, 1871, Nomada goodeniana (Kirby, 1802), Nomada ruficornis (Linnaeus, 1758) and Eucera nigrescens Pérez, 1879, four of which are also new for the Transcaucasia region. With these additions, the number of bee species known to occur in Georgia increases to 371.     

Range expansion of the Asian native giant resin bee Megachile sculpturalis (Hymenoptera,Apoidea, Megachilidae) in France

In 2008, a new species for the French bee fauna was recorded in Allauch near Marseille: the giant resin bee, Megachile sculpturalis (Smith, 1853). This was the first European record of this species that is native to East Asia. To our knowledge, it is the first introduced bee species in Europe. Here, we provide an overview of the current distribution of M. sculpturalis in France and we describe the history of its range expansion. Besides our own observations, information was compiled from literature and Internet websites, and by contacting naturalist networks. We collected a total of 117 records (locality × year combinations) for the 2008–2016 period. The geographical range of M. sculpturalis has extended remarkably, now occupying a third of continental France, with the most northern and western records located 335 and 520 km from Allauch, respectively. Information on its phenology, feeding, and nesting behavior is also provided. We report several events of nest occupation or eviction of Osmia sp. and Xylocopa sp. individuals by M. sculpturalis. Our results show that M. sculpturalis is now well established in France. Given its capacity to adapt and rapidly expand its range, we recommend amplifying the monitoring of this species to better anticipate the changes in its geographical range and its potential impacts on native bees.     

Foraging behavior of bee pollinators on the tropical weed Triumfetta semitriloba: flight distance and directionality

We studied flight distance and directionality of bee pollinators on the tropical shrub weed Triumfetta semitriloba Jacq. (Tiliaceae), addressing (1) within- and between-plant movement pattern; (2) distances flown between plants; (3) flight directionality. Flowering plants were distributed in well-delimited clumps, in each of two pasture areas (A1 and A2) and one area of forest gap (A3), in Vi?osa, southeastern Brazil. Five solitary bee species, Augochlorella michaelis, Augochloropsis cupreola, Pseudocentron paulistana, Ceratinula sp., Melissodes sexcincta, and two social bee, Plebeia droryana, P. cf. nigriceps were observed. All species moved mainly to the nearest flower on the same individual plant and, in between-plant movements, to the first or second nearest neighbor. All species moved non-randomly, presenting a flight directionality in departures (maintenance of flight direction), but with a high frequency of turn angles. It is suggested that this foraging behavior pattern occurred because of the resource quantity and quality (pollen or nectar), and environmental characteristics such as flower density and resource distribution.     

Nest sites,breeding cycle and possible cleptoparasites of Monoeca catarina Aguiar (Hymenoptera,Apidae, Tapinotaspidini) from Santa Catarina Island,southern Brazil

ABSTRACT

The recently described solitary bee Monoeca catarina Aguiar (Apidae, Tapinotaspidini) is only known from two nest aggregations on Santa Catarina Island, state of Santa Catarina, southern Brazil. Nests are excavated in sandy soils along trails near dunes and beaches. Up to 287 nests were counted in one aggregation. Bees were active for about seven weeks from late November to mid-January suggesting a univoltine life cycle. Males perform patrolling flights over the nest area and mate with females sitting on low vegetation. Males and females visited Stachytarpheta cayennensis (Verbenaceae) for nectar, and females were observed foraging on Tetrapterys sp. or Heteropterys sp. flowers (Malpighiaceae). Pollen loads consisted almost exclusively of Malpighiaceae pollen. Potential natural enemies are the cleptoparasitic bee Protosiris Roig-Alsina sp. (Apidae, Osirini) recorded within the aggregations, and the mutillid wasp Hoplocrates specularis (Gerstaecker) (Mutillidae, Sphaeropthalmini) seen entering the Monoeca nests and mating within the aggregations. Except for the soil characteristics, our observations on nesting and foraging behavior and associated potential enemies fit well into the facts reported from other Monoeca species.     

双斑切叶蜂的筑巢习性

【目的】明确双斑切叶蜂Megachile leachella在沙地上的筑巢环境及筑巢特点,旨在当地利用人工巢管诱引其筑巢。【方法】采用目测和拍照等方法对双斑切叶蜂的整个筑巢过程进行了连续观察; 采用挖掘、测量方法对双斑切叶蜂巢内结构进行了观测;在室内对蜂茧在土中和指形管中的羽化情况进行了初步观测。【结果】双斑切叶蜂一般在废弃的泥墙或者沙地上蚂蚁等废弃的巢穴中筑巢,有时候它也在沙地上挖掘新巢筑巢。双斑切叶蜂用叶片构建巢室,一巢多室,各巢室首尾相接排列在巢中,筑完巢后用叶片将巢口封住。双斑切叶蜂构建一个巢室需要切取11～14片叶子,为每巢室采集蜂粮6～9次,每巢室内产卵1粒;在内蒙古毛乌素沙地,该蜂一年2代,第1代在6月中下旬羽化,第2代大约在7月下旬至8月上旬羽化,主要寄生性天敌有尖腹蜂Coelioxy sp.、青蜂Chrysis sp.。双斑切叶蜂能在指形管中羽化。【结论】双斑切叶蜂不同个体之间的筑巢行为相似,雌蜂可以用人工巢管进行诱集和驯化。     

Population dynamics of the solitary digger bee<Emphasis Type="Italic"> Andrena vaga</Emphasis> Panzer (Hymenoptera,Andrenidae) studied using mark-recapture and nest counts

The population size of the solitary digger bee Andrena vaga was documented using mark-recapture methods during 4 consecutive years (1996–1999). Additionally, the numbers of the parasitoids Nomada lathburiana and Bombylius major were estimated. For calculations of the daily population size, the Jolly-Seber model for open populations with time-dependent survival and capture rates was used. The mean daily population size corresponded well to the number of nests marked in the aggregation of A. vaga. The method of mark-recapture achieved the most accurate data when the number of sampling periods and the capture probability was high. The results document a decrease in population size of the investigated A. vaga aggregation during 4 successive years. A population increase of its parasitoids B. major is considered to be one reason for the population decline of A. vaga in 1999. The sex ratio of A. vaga was biased toward females, contrary to the expected higher number of males. Results of the mark-recapture studies showed that up to 50% of females left the aggregation or died at the beginning of the season. The females probably colonized new aggregations at distances further than 200 m away from their birth aggregation, as no marked females were observed in the environs of the study area. This behavior is interpreted as a parasite avoidance strategy. The bee populations in the study area form a web of interconnected aggregations. Apparently a flux of extinction and recolonization exists between the different aggregations.     

Bioactive Attributes and Analysis of Electronic Nose Feature Signals of Colombian Stingless Bees Propolis

The volatile and non-volatile chemical composition and bioactivity of propolis from the species Apis mellifera has been widely studied, but there is very little knowledge regarding propolis of other bee species, which ultimately hinders their differentiation and potential use. In this work, 53 propolis samples of A. mellifera and four stingless bee species (Frieseomielitta sp., Melipona eburnea, Melipona sp., and Trigona sp.) were collected in Colombia. An electronic nose with 10 metal oxide semiconductor sensors (MOS) was used to generate a pattern of the representative volatile compounds of the samples. Ethanolic extracts were obtained to assess their antioxidant activity towards DPPH radical and ABTS radical cation, total phenolics, and color (CIELAB space). The results showed an overall similarity of the aromatic profiles between species. The antioxidant activity of Frieseomielitta sp. propolis was higher than that of A. mellifera and the other species, in correspondence with a higher phenolic content. CIELAB color parameter b* was the most differentiating variable among samples, indicating a variation of propolis colors between red and yellow. By combining the data from physico-chemical analysis and aromatic profile, it was possible to differentiate the propolis from each bee species, with the exception of those from Melipona sp. and Trigona sp., indicating their similarity. These results have practical significance since they are a starting point to recognizing and valuing native stingless bee propolis and their bioactive potential, which, in addition to geographical differentiation and further quality parameters evaluation, will enhance their commercial exploitation.     

Distance from forest edge affects bee pollinators in oilseed rape fields

Wild pollinators have been shown to enhance the pollination of Brassica napus (oilseed rape) and thus increase its market value. Several studies have previously shown that pollination services are greater in crops adjoining forest patches or other seminatural habitats than in crops completely surrounded by other crops. In this study, we investigated the specific importance of forest edges in providing potential pollinators in B. napus fields in two areas in France. Bees were caught with yellow pan traps at increasing distances from both warm and cold forest edges into B. napus fields during the blooming period. A total of 4594 individual bees, representing six families and 83 taxa, were collected. We found that both bee abundance and taxa richness were negatively affected by the distance from forest edge. However, responses varied between bee groups and edge orientations. The ITD (Inter‐Tegular distance) of the species, a good proxy for bee foraging range, seems to limit how far the bees can travel from the forest edge. We found a greater abundance of cuckoo bees (Nomada spp.) of Andrena spp. and Andrena spp. males at forest edges, which we assume indicate suitable nesting sites, or at least mating sites, for some abundant Andrena species and their parasites (Fig.  1 ). Synthesis and Applications. This study provides one of the first examples in temperate ecosystems of how forest edges may actually act as a reservoir of potential pollinators and directly benefit agricultural crops by providing nesting or mating sites for important early spring pollinators. Policy‐makers and land managers should take forest edges into account and encourage their protection in the agricultural matrix to promote wild bees and their pollination services.

Figure 1 Open in figure viewer PowerPoint Left, a Nomada sp male; right, an Andrena sp male. Caption Left, a Nomada sp male; right, an Andrena sp male.

Introduction

Pollinators play an important functional role in most terrestrial ecosystems and provide a key ecosystem service (Ashman et al. 2004 ). Insects, particularly bees, are the primary pollinators for the majority of the world's angiosperms (Ollerton et al. 2012 ). Without this service, many interconnected species and processes functioning within both wild and agricultural ecosystems could collapse (Kearns et al. 1998 ). Brassica napus (oilseed rape, OSR) represents the most widespread entomophilous crop in France with almost 1.5 Mha in 2010 (FAOSTAT August 10th, 2012). Results differ between varieties, but even though it seems that OSR produces 70% of its fruits through self‐pollination (Downey et al. 1970 in Mesquida and Renard 1981 ), native bees are also known to contribute to its pollination (Morandin and Winston 2005 ; Jauker et al. 2012 ). Bee pollination leads to improved yields (Steffan‐Dewenter 2003b ; Sabbahi et al. 2005 ) and to a shorter blooming period (Sabbahi et al. 2006 ), thus increasing the crop's market value (Bommarco et al. 2012 ). The most widely used species in crop pollination is the honeybee (Apis mellifera L) which is sometimes assumed to be sufficient for worldwide crop pollination (Aebi and Neumann 2011 ). However, this assertion has been questioned by different authors (Ollerton et al. 2012 ), and several studies show that many wild bees are also efficient pollinators of crops (Klein et al. 2007 ; Winfree et al. 2008 ; Breeze et al. 2011 ). Recently, Garibaldi et al. ( 2013 ) found positive associations of fruit set with wild‐insect visits to flowers in 41 crop systems worldwide. They demonstrate that honeybees do not maximize pollination, nor can they fully replace the contributions of diverse, wild‐insect assemblages to fruit set for a broad range of crops and agricultural practices on all continents with farmland. Unfortunately, not only are honey bees declining due to a variety of different causes (vanEngelsdorp et al. 2009 ), wild bee populations are also dwindling (Potts et al. 2010 ). Their decline has been documented in two Western European countries (Britain and the Netherlands) by comparing data obtained before and after 1980 (Biesmeijer et al. 2006 ). These losses have mostly been attributed to the use of agrochemicals, the increase in monocultures, the loss of seminatural habitat and deforestation (Steffan‐Dewenter et al. 2002 ; Steffan‐Dewenter and Westphal 2008 ; Brittain and Potts 2011 ). Several studies have shown the importance of natural or seminatural habitats in sustaining pollinator populations or pollination services close to fruit crops (Steffan‐Dewenter 2003a ; Kremen et al. 2004 ; Greenleaf and Kremen 2006a ; Carvalheiro et al. 2010 ). Morandin and Winston ( 2006 ) presented a cost–benefit model that estimates profit in OSR agroecosystems with different proportions of uncultivated land. They calculated that yield and profit could be maximized with 30% of the land left uncultivated within 750 m of field edges. Other studies have demonstrated a negative impact of the distance from forests on pollination services or bee abundance and richness both in tropical ecosystems (De Marco and Coelho 2004 ; Blanche et al. 2006 ; Chacoff and Aizen 2006 ) and in temperate ecosystems (Hawkins 1965 ; Taki et al. 2007 ; Arthur et al. 2010 ; Watson et al. 2011 ). These studies all suggest that natural or seminatural habitats are important sources of pollinators, probably because they provide “partial habitats” (Westrich 1996 ) such as complementary mating, foraging, nesting, and nesting materials sites that bees need to complete their life cycle. In this study, we focused on the effect of distance to forest edge on bee assemblages in OSR ecosystems. Forest edges could provide one or more important partial habitats for different bee species in agricultural landscapes, in particular when associated with a mass‐flowering crop such as OSR (Le Feon et al. 2011 ). For example, the availability of untilled soil and dead branches might provide ground‐nesting and cavity‐nesting bee species with numerous nesting sites. Moreover, during spring at least, the understory and the forest edge can provide cover containing flowering plants and wild trees such as Prunus spp, Castanea sativa, or Salix spp and thereby allow bees to find alternative floral resources. During spring 2010 and 2011, in two areas in France, we examined wild bee abundance and taxa richness both along forest edges and inside OSR fields at different distances from the forest. Like other taxa, bees respond to environmental variables according to their biologic traits that determine access and requirements for nesting, mating, and forage resources, species mobility or physiological tolerance. Specifically, we hypothesized that (1) bee abundance, species richness, and composition of bee communities within the crop field are dependent on the distance from the forest edge (where complementary floral resources, nesting sites, shelters, etc. can be found) and on the orientation of the forest edge; (2) the identity of bees in the crop is related to their foraging range which we measured with the ITD (Inter‐Tegular distance); (3) the forest edge may be the nesting or mating sites for cavity‐nesting or ground‐nesting bees such as Osmia spp or Andrena spp which are important groups of potential early spring pollinators for OSR.     

蜜蜂肠道菌群结构功能研究进展

在长期的共同进化中,肠道菌群与其宿主形成了紧密的联系,为宿主提供了许多有益的作用。作为一种社会性昆虫,蜜蜂的生活习性为其肠道菌群提供了良好而稳定的传播途径,因此,蜜蜂与其肠道菌群形成了一种紧密的互惠互利共生关系。近年来,随着对蜜蜂肠道菌群了解的不断加深,对蜜蜂肠道菌群功能的研究也不断深入,大量研究表明蜜蜂的肠道菌群在宿主食物的消化代谢、宿主免疫的激活和抵抗致病菌、调节宿主生理等方面都有着重要的作用,同时破坏肠道菌群的稳定对蜜蜂的健康有着明显的负面影响。本文对近年来西方蜜蜂肠道菌群功能研究进行了总结,旨在为进一步深入探索蜜蜂肠道菌群与其宿主的相互作用及在养蜂生产上应用肠道菌群防控疾病提供参考。     

Use of human-made nesting structures by wild bees in an urban environment

Most bees display an array of strategies for building their nests, and the availability of nesting resources plays a significant role in organizing bee communities. Although urbanization can cause local species extinction, many bee species persist in urbanized areas. We studied the response of a bee community to winter-installed human-made nesting structures (bee hotels and soil squares, i.e. 0.5 m deep holes filled with soil) in urbanized sites. We investigated the colonization pattern of these structures over two consecutive years to evaluate the effect of age and the type of substrates (e.g. logs, stems) provided on colonization. Overall, we collected 54 species. In the hotels, two gregarious species, Osmia bicornis L. and O. cornuta Latr. dominated the community (over 87 % of the data). Over 2 years, the age of the soil squares did not affect their level of colonization and the same was true for the hotels with respect to O. bicornis and ‘other species’. However, O. cornuta occurred less often and raised fewer descendants in 1-year old hotels than in new ones. Bee nesting was not affected by the soil texture and, among above-ground nesting bees, only O. bicornis showed a preference for some substrates, namely Acer sp. and Catalpa sp. In a context of increasing urbanization and declining bee populations, much attention has focused upon improving the floral resources available for bees, while little effort has been paid to nesting resources. Our results indicate that, in addition to floral availability, nesting resources should be taken into account in the development of urban green areas to promote a diverse bee community.