异色瓢虫--简单而方便的遗传学实验材料

瓢虫是一种在庭院、野外 ,甚至在儿童的绘画书中经常见到的昆虫。按瓢虫科中的种类计算 ,世界上约有4 9 0属 ,4 0 0 0种之多 ,其中大多数瓢虫属于害虫天敌。据 Gordon(1985)估计 ,分布在北美和墨西哥的 4 75种瓢虫中 ,仅 4种为植食性 ,6种为菌食性。另据 Sasaji(1985)的统计 ,分布在日本的瓢虫 ,全部 162种中仅 8种为植食性 ,4种为菌食性。此外 ,我国有正式记录的32 6种瓢虫中 ,植食性的为 71种 ,菌食性的为 11种 ,其余的均为捕食性瓢虫 (庞雄飞 1991) ,其捕食对象为蚜虫、螨、芥壳虫等害虫。事实上 ,自然界中至今仍存在大量有待描述的瓢虫…     

捕食者对空心莲子草叶甲种群的生物胁迫

广食性捕食者广泛捕食植食性昆虫,常被用于有害生物的生物防治,也因此影响植食性昆虫对杂草的生物效果。空心莲子草叶甲(Agasicles hygrophila)(鞘翅目:叶甲科Chrysomelidae)作为入侵恶性杂草空心莲子草(Alternanthera philoxeroides)(苋科:莲子草属Alternanthera)的专性天敌,从美国的弗罗里达州引入中国,在释放地防治空心莲子草取得了较好的防治效果。虽然空心莲子草叶甲在引入地均已建立田间种群并有一定程度的自然扩散,但丰富的食物资源,并未使空心莲子草叶甲的自然种群数量变得繁荣,因此其未能有效抑制空心莲子草的扩散蔓延。在野外调查时发现空心莲子草生境中存在大量广食性捕食者。这些广食性捕食者是抑制空心莲子草叶甲种群数量扩张的生物胁迫因子吗?为此,选择捕食性昆虫龟纹瓢虫(Propylaea japonica)(鞘翅目:瓢虫科Coccinellidae)、蜘蛛类捕食者拟水狼蛛(Pirata subpiraticus)(蜘蛛目:狼蛛科Lycosidae)与斜纹猫蛛(Oxyopes sertatus)(蜘蛛目:猫蛛科Oxyopidae)为捕食者,分别以空心莲子草叶甲各虫态为猎物,构建简单的捕食者-猎物系统,在室内检测了上述3种捕食者对空心莲子草叶甲各虫态在不同密度下的日捕食量,以期了解捕食者对空心莲子草叶甲的捕食作用,客观评估空心莲子草叶甲的生物防治效能。研究结果表明:捕食者龟纹瓢虫、斜纹猫蛛与拟水狼蛛均捕食空心莲子草叶甲的卵粒及1龄、2龄幼虫,斜纹猫蛛与拟水狼蛛捕食3龄幼虫,捕食者的捕食量均随着猎物密度的升高而增加,寻找效应降低。三者均不捕食成虫。除拟水狼蛛对3龄幼虫的捕食用Holling II模型拟合不呈显著相关关系外,其余捕食反应均拟合Holling II模型并显著相关。通过拟合方程得出捕食者对空心莲子草叶甲卵粒的理论日最大捕食量为:斜纹猫蛛10.9粒,拟水狼蛛为6.2粒,龟纹瓢虫为5.6粒;对1龄幼虫的理论日最大捕食量为:斜纹猫蛛为17.1头;拟水狼蛛为35.8头,龟纹瓢虫为10.4头;对2龄幼虫的理论日最大捕食量为:斜纹猫蛛为6.6头,拟水狼蛛为11.2头,龟纹瓢虫为2.9头;对3龄幼虫的理论日最大捕食量为:斜纹猫蛛捕食12.3头,拟水狼蛛为1.1头。研究结果证实了捕食者可通过捕食作用降低空心莲子草叶甲种群密度,削弱空心莲子草叶甲对空心莲子草的控害效能,是空心莲子草叶甲种群存活的生物胁迫因子。建议在提高空心莲子草叶甲田间种群数量,达到对空心莲子有效的持续控制效果方面开展进一步研究。     

捕食性瓢虫的体型大小影响其偏好捕食防御性强的猎物吗?（英文）

【目的】尽管瓢虫表现出种间和种内特异性体型大小的变异,但是瓢虫体型大小的变异是否会改变其选择捕食防御性强(即表现出各种防御反应,包括积极躲避捕食、挣脱捕食者或频繁利用防御性化学物质)的猎物,这一问题尚不清楚。本研究中,我们假设不论体型大小,捕食性瓢虫七星瓢虫Coccinella septempunctata(L.)和六斑月瓢虫Menochilus sexmaculatus(Fab.)都将增加其对猎物萝卜蚜Lipaphis erysimi(Kaltenbach)的捕食,只要猎物处于防御性强的龄期,原因是处于防御性强的龄期的猎物体型大且更有活力。【方法】我们将萝卜蚜4龄若虫期作为防御性强的龄期,将2龄若虫期作为防御性弱的龄期,评价七星瓢虫和六斑月瓢虫这两种瓢虫的大型和小型变异体对萝卜蚜的偏好性。【结果】结果表明,六斑月瓢虫的大型和小型雌性变异体更多地捕食防御性弱的萝卜蚜,而七星瓢虫的大型和小型雌性变异体分别对防御性强和防御性弱的萝卜蚜捕食较多。在混合饲料上,七星瓢虫雌性变异体对两类蚜虫的捕食百分比相似,而六斑月瓢虫变异体对防御性弱的萝卜蚜的捕食百分比较高。尽管随着七星瓢虫雌虫体型的增大而对两类猎物的捕食增多,但随着六斑月瓢虫雌虫体型的增大,只对防御性强的蚜虫的捕食量增加。【结论】本研究结果与我们的假设相反,并证明了:(1)小型瓢虫更多地只是捕食防御性弱的猎物,而大型瓢虫选择性地捕食防御性强的猎物;(2)在瓢虫种内和种间,随着捕食者体型的增大,对防御性强的猎物的偏好性增加。可将这些结果用于瓢虫的室内大规模饲养,以提高对萝卜蚜的生物防治。     

广东南岭国家自然保护区大东山捕食性昆虫及其食性分析

本文报道了广东省国家自然保护区大东山捕食性昆虫(含蜘蛛)的种类与食性.全文主要内容分为两部分:捕食性昆虫种类和捕食性昆虫食性分析.食性分析包括捕食性昆虫栖息习性和各目捕食性昆虫的捕食能力.     

长白山阔叶红松林植物群落与昆虫群落的相互关系研究

通过季节性的观察,系统研究了长白山植物群落、昆虫群落多样性及它们之间关系。结果表明,植物群落物种丰富度指数与植食性昆虫丰富度指数呈负相关,而与捕食性天敌昆虫丰富度指数呈正相关,与寄生性天敌的丰富度指数呈负相关;昆虫群落的均匀度与植物群落的均匀度相关显著。植物群落的多样性指数与捕食性、寄生性天敌的多样性指数呈正相关。而与植食性昆虫的多样性指数呈负相关,这表明植物群落的多样性影响昆虫群落的多样性。     

麦田昆虫群落的结构与时序动态

采用目测法和网捕法 ,通过对小麦整个生长季节内昆虫群落的系统调查 ,共查得昆虫11目 2 3科 36种 ,其中捕食性昆虫有 4目 5科 12种、寄生性昆虫有 2目 3科 4种、植食性昆虫有 5目 12科 15种、粪食性等其他类昆虫有 1目 3科 5种。在捕食性天敌昆虫中 ,瓢虫的种类和数量最多 ,其次为草蛉和食蚜蝇 ;在寄生性天敌昆虫中 ,蚜茧蜂为优势种 ,其次为寄蝇 ;在植食性昆虫中 ,麦长管蚜为绝对的优势种 ,其次为赤须盲蝽、灰飞虱和麦蓟马。天敌昆虫对害虫具有明显的跟随现象 ,不能有效地控制麦长管蚜的发生与危害。依据昆虫群落的组成与结构 ,结合小麦生育期 ,采用最优分割法将麦田昆虫群落动态划分为 5个阶段 ,并指出不同阶段昆虫群落特点及相应的害虫防治策略。     

生态生物化学(八):植食性昆虫对食物的选择

动物取食的习性,即对食物的选择性,是在漫长的历史进化中形成的。昆虫种类繁多,这与其食性的分化是分不开的。昆虫的食性多种多样,有植食性的,即以植物及其产物为食的;有肉食性的,即以动物为食,包括捕食性     

荒漠草原地面节肢动物功能群对草地封育的响应

以宁夏盐池国家级草原资源生态监测站为依托,选择荒漠草原典型植被类型的封育与未封育样地调查了地面节肢动物、植被及土壤特征,同时根据动物食性对节肢动物功能群进行了划分.结果表明:荒漠草原地面节肢动物可划分为捕食性、植食性、腐食性和杂食性4种营养功能群.其中,植食性和捕食性节肢动物在数量上占优势,植食性和腐食性节肢动物生物量所占比例较大,表明荒漠草原地面节肢动物区系以植食性动物分布为其主要特征.围栏封育增加了捕食性、植食性和杂食性节肢动物个体数量和类群数,增加了捕食性和杂食性节肢动物的生物量,提高了捕食性和植食性节肢动物的物种多样性,这与植被恢复和土壤环境改善密切相关,说明荒漠草原围栏封育增加了地面节肢动物功能群的多样性和复杂性.但是围栏封育后,腐食性节肢动物个体数量减少,生物量降低,反映了腐食性节肢动物对放牧草地生境的依赖性.     

干旱绿洲区枸杞林地面节肢动物功能群结构季节分布特征

为了解枸杞林地面节肢动物功能群结构季节分布特征,以宁夏绿洲枸杞林为研究对象,于2018年的春、夏、秋季节,采用陷阱诱捕法,调查了地面节肢动物功能群季节分布特征及其与环境因子之间的关系。结果显示:(1)枸杞林地面节肢动物功能群包括植食性、捕食性、腐食性和杂食性动物,个体数分别占6.31%、86.75%、2.01%和4.89%,其中以捕食性动物为主。(2)植食性地面节肢动物个体数和生物量表现为春季显著高于秋季,夏季居中;类群数表现为夏季显著高于秋季,春季居中。捕食性地面节肢动物生物量表现为夏季和秋季显著高于春季;个体数和类群数在不同季节间均无显著差异。腐食性地面节肢动物个体数、生物量和类群数在不同季节间均无显著差异。杂食性地面节肢动物个体数和类群数表现为春季显著高于夏季,秋季居中;生物量在不同季节间均无显著差异。(3)相关分析表明,捕食性地面节肢动物个体数与土壤含水量呈正相关关系,腐食性地面节肢动物个体数与土壤全磷呈正相关关系,杂食性地面节肢动物与土壤全氮呈正相关关系。但植食性地面节肢动物个体数则与土壤含水量呈负相关关系,杂食性地面节肢动物个体数与土壤温度和土壤全碳呈负相关关系。(4)pRDA分析表明,土壤含水量是影响地面节肢动物功能群结构季节分布的主要环境因子。结论:随着季节更替,宁夏干旱绿洲区枸杞林地面节肢动物的功能群组成差异较大,功能多样性差异较小。说明每个功能群的个体数和类群数对季节变化敏感,但功能多样性较稳定。     

瓢虫和草蛉对小麦挥发物组分的行为及电生理反应

利用触角电位（electroantennogram, EAG）和嗅觉测定技术,比较分析了4种捕食性天敌昆虫七星瓢虫Coccinella septempunctata、龟纹瓢虫Propylaea japonica、中华通草蛉Chrysoperla sinica和大草蛉Chrysopa septempunctata对麦蚜取食诱导小麦挥发物的行为和电生理反应,揭示了瓢虫及草蛉类天敌昆虫的嗅觉反应特点。4种捕食性天敌昆虫对麦蚜取食诱导挥发物都有较高的EAG反应值,七星瓢虫和龟纹瓢虫对6-甲基-5_庚烯-2-酮、6-甲基-5-庚烯-2-醇的反应值较大;中华通草蛉和大草蛉对6-甲基-5-庚烯-2-醇和水杨酸甲酯的反应值较大,七星瓢虫对6-甲基-5-庚烯-2-醇的反应值最大,为0.96±0.18 mV;4种天敌昆虫对苯甲醛的EAG反应值较低,对反-2-己烯醛无反应。“Y”型管嗅觉测定结果表明,4种天敌昆虫对2-莰烯、6-甲基-5-庚烯-2-酮、6-甲基-5-庚烯-2-醇和水杨酸甲酯具有正趋性。说明4种多食性的捕食性天敌昆虫对麦蚜取食诱导挥发物各组分的嗅觉与行为反应各具特点;寄主麦蚜生境中的嗅觉线索在这4种捕食性天敌昆虫的寄主定位和生境选择中起重要作用。     

Weapon allometry varies with latitude in the New Zealand giraffe weevil

Animal body size commonly shows a relationship with latitude to the degree that this phenomenon is one of the few ‘rules’ discussed in evolutionary ecology: Bergmann's rule. Although exaggerated secondary sexual traits frequently exhibit interesting relationships with body size (allometries) and are expected to evolve rapidly in response to environmental variation, the way in which allometry might interact with latitude has not been addressed. We present data showing latitudinal variation in body size and weapon allometry for the New Zealand giraffe weevil (Lasiorhynchus barbicornis). Males display an extremely elongated rostrum used as a weapon during fights for access to females. Consistent with Bergmann's rule, mean body size increased with latitude. More interestingly, weapon allometry also varied with latitude, such that lower latitude populations exhibited steeper allometric slopes between weapon and body size. To our knowledge, this is the first study to document a latitudinal cline in weapon allometry and is therefore a novel contribution to the collective work on Bergmann's rule and secondary sexual trait variation.     

Do males with higher mating success invest more in armaments? An across‐populations study in damselflies

1. Males with higher mating success would be expected to invest more in traits that facilitate mating, leading to steeper allometry of those traits with respect to body size. Across‐population studies following latitudinal variation in male mating success are an excellent study system to address this question. 2. Males of the damselfly Lestes sponsa were used to investigate whether the allometric patterns of the length and width of the anal appendages, used for grasping the female prior to mating, corresponded to male mating success. Across a large latitudinal gradient, it was hypothesised that there is a larger investment in the grasping apparatus, i.e. a steeper allometric slope, following higher mating success. 3. Behavioural observations in field enclosures showed the highest mating success at high latitude, while there were no significant differences in mating success between the central and low latitudes. Positive allometry was found for the length of the anal appendages in high‐latitude males, while central‐ and low‐latitude males showed no significant regressions of the traits on body size. 4. These results partially support the hypothesis, as high‐latitude, more successful males invested more in the length (but not the width) of the grasping apparatus than did central‐ and low‐latitude males. Therefore, higher mating success might be facilitated by larger investment in armaments. Intraspecific studies on allometric patterns of traits that participate in mating success might offer new insights into the role of those traits in the reproductive behaviour of a species.     

Phenotypic variability of quantitative traits in Indian populations of Drosophila kikkawai

Drosophila kikkawai, which has colonized the Indian subcontinent in the recent past, exhibits geographical variations for five quantitative traits among eight Indian populations (8.29–32.7°N). Body weight, wing length, thorax length, abdominal bristles and ovariole number exhibit significant clinal variation with increase in latitude, while sternopleural bristles do not demonstrate such a trend. For the female sex, the slope values for body weight (2.25) and wing length (2.40) are higher but they are lower for thorax length (0.64) and ovariole number (0.51 per degree latitude). There is significant sexual dimorphism for the slope values only for body weight and thorax length suggesting simultaneous action of latitudinal selection pressure on these traits. However, the two sexes do not differ statistically in the latitudinal slope values for the wing length. A regression analysis of different traits on body weight implies correlated selection response on wing length and wing/thorax ratio while thorax length corresponds to changes in body size and does not differ in the two sexes. Regression analysis, on the basis of temperature-related climatic variables, evidence significantly higher association between all the five size-related traits and coefficient of variation of mean annual temperature (seasonal thermal amplitude; T _cv), T _min and relative humidity. Thus, genetic differentiation for quantitative traits in D. kikkawai are due to selective pressure from variable climatic conditions occurring on the Indian subcontinent.     

Latitudinal variation and coevolutionary diversification of sexually dimorphic traits in the false blister beetle Oedemera sexualis

Sexual traits are subject to evolutionary forces that maximize reproductive benefits and minimize survival costs, both of which can depend on environmental conditions. Latitude explains substantial variation in environmental conditions. However, little is known about the relationship between sexual trait variation and latitude, although body size often correlates with latitude. We examined latitudinal variation in male and female sexual traits in 22 populations of the false blister beetle Oedemera sexualis in the Japanese Archipelago. Males possess massive hind legs that function as a female‐grasping apparatus, while females possess slender hind legs that are used to dislodge mounting males. Morphometric analyses revealed that male and female body size (elytron length), length and width of the hind femur and tibia, and allometric slopes of these four hind leg dimensions differed significantly among populations. Of these, three traits showed latitudinal variation, namely, male hind femur was stouter; female hind tibia was slenderer, and female body was smaller at lower latitudes than at higher latitudes. Hind leg sizes and shapes, as measured by principal component analysis of these four hind leg dimensions in each sex, covaried significantly between sexes, suggesting coevolutionary diversification in sexual traits. Covariation between sexes was weaker when variation in these traits with latitude was removed. These results suggest that coevolutionary diversification between male and female sexual traits is mediated by environmental conditions that vary with latitude.     

Geographic variation in body size and sexual size dimorphism of a seed-feeding beetle

Body size of many animals varies with latitude: body size is either larger at higher latitudes (Bergmann's rule) or smaller at higher latitudes (converse Bergmann's rule). However, the causes underlying these patterns are poorly understood. Also, studies rarely explore how sexual size dimorphism varies with latitude. Here we investigate geographic variation in body size and sexual size dimorphism of the seed-feeding beetle Stator limbatus, collected from 95 locations along a 38 degrees range in latitude. We examine 14 variables to test whether clines in environmental factors are adequate to explain geographic patterns of body size. We found that body size and sexual size dimorphism of S. limbatus varied considerably with latitude; beetles were smaller but more dimorphic at lower latitudes. Body size was not correlated with a gradient in mean temperature, contrary to the commonly accepted hypothesis that clines are produced by latitudinal gradients in temperature. Instead, we found that three factors were adequate to explain the cline in body size: clinal variation in host plant seed size, moisture (humidity), and seasonality (variance in humidity, precipitation, and temperature). We also found that the cline in sexual size dimorphism was partially explainable by a gradient in moisture, though moisture alone was not sufficient to explain the cline. Other ecological or environmental variables must necessarily contribute to differences in selection on male versus female body size. The main implications of our study are that the sexes differ in the magnitude of clinal variation in body size, creating latitudinal variation in sexual size dimorphism, and that clines in body size of seed beetles are likely influenced by variation in host seed size, water availability, and seasonality.     

Latitudinal variation in sexual dimorphism in life‐history traits of a freshwater fish

Sexual dimorphism is common across the animal kingdom, but the contribution of environmental factors shaping differences between the sexes remains controversial. In ectotherms, life‐history traits are known to correlate with latitude, but sex‐specific responses are not well understood. We analyzed life‐history trait variation between the sexes of European perch (Perca fluviatilis L.), a common freshwater fish displaying larger female size, by employing a wide latitudinal gradient. We expected to find sex‐dependent latitudinal variation in life‐history variables: length at age, length increment, and size at maturity, with females showing consistently higher values than males at all latitudes. We further anticipated that this gender difference would progressively decrease with the increasingly harsh environmental conditions toward higher latitude. We hypothesized that growth and length increment would decrease and size/age at maturity would increase at higher latitudes. Our results confirmed female‐biased sexual size dimorphism at all latitudes and the magnitude of sexual dimorphism diminished with increase in latitude. Growth of both sexes decreased with increase in latitude, and the female latitudinal clines were steeper than those of males. Hence, we challenge two predominant ecological rules (Rensch's and Bergmann's rules) that describe common large‐scale patterns of body size variation. Our data demonstrate that these two rules are not universally applicable in ectotherms or female‐biased species. Our study highlights the importance of sex‐specific differences in life‐history traits along a latitudinal gradient, with evident implications for a wide range of studies from individual to ecosystems level.     

Latitudinal pattern in body size in a cockroach,Eupolyphaga sinensis

Body size of insects with flexible life cycles is expected to conform to the saw‐tooth model, a model in which the relationship between size and developmental time depends on length of the growing season. In species with high variability in terms of voltinism, however, more complex patterns can be expected. Few empirical studies have demonstrated the existence of such relationships, or whether climatic factors contribute to these relationships. In this study, we investigated the geographic variation in body size of the Chinese cockroach, Eupolyphaga sinensis Walker (Blattaria: Polyphagidae), which has a variable life cycle length. The sizes of adults – collected from 14 localities ranging from temperate to subtropical zones in China – were measured, using body length, body width, and pronotum width as parameters. The relationship between size, latitude, and climate factors (encompassing 10 variables) was then investigated. We found that the body size of E. sinensis varied considerably with latitude: cockroaches were larger at low and high latitudes, but smaller at intermediate latitudes. Thus, the relationship between climate and body size conformed to a saw‐tooth pattern. Results indicate that two factors were significantly associated with body size clines: season length and variability in life cycle length. Our results also demonstrated that climatic factors contribute to latitudinal clines in body size, which has important ecological and evolutionary implications. It can be expected that global climate change may alter latitudinal clines in body size of E. sinensis.     

Allometry in damselfly ornamental and genital traits: solving some pitfalls of allometry and sexual selection

Static allometry of sexually selected traits has been the subject of intense research recently. However, some pitfalls for this kind of research are: (a) the functions of sexual traits are largely unknown; (b) more than one body size indicator must be measured; and, (c) allometry must be examined under different environmental circumstances to see whether allometric values change. Using Hetaerina americana damselflies, we investigated the type of allometry exhibited by a wing red spot and aedeagal width. These traits are positively selected during pre-copulatory male-male contests and post-copulatory female stimulation, respectively. As body size indicators, we used wing length and head width. It has been documented that expression of both sexual traits varies throughout the year. Thus, allometry was examined in different times of the year. We also investigated the allometry of aedeagal width and vaginal width at the zone where female stimulation takes place. We found no clear pattern of any allometric relationship for male and female traits and for both body size indicators at all times sampled. Our results contrast with patterns of negative allometry exhibited by genital traits in other animals.     

Latitudinal variation in wild populations of Drosophila melanogaster: heritabilities and reaction norms

Large amounts of genetic variation for wing length and wing area were demonstrated both within and between Drosophila melanogaster populations along a latitudinal gradient in South America. Wing length and wing area showed a strong positive correlation with latitude in both wild flies and laboratory-raised descendants. Large population differences were observed for heritability and coefficient of variation of these two traits, whereas relatively small population differences were found for development time, viability, pupal mortality, sex ratio and their norms of reaction to four developmental temperatures. No clear-cut latitudinal clines were established for these life-history characters. These results are discussed in the light of Bergmann's Rule and the relation between larval development and adult body size.     

Flight morphology along a latitudinal gradient in a butterfly: do geographic clines differ between agricultural and woodland landscapes?

Bergman and converse Bergman rules, amongst others, describe latitudinal variation in size of organisms, including flying ectotherms like butterflies. However, geographic clines in morphological traits of functional significance for flight performance and thermoregulation may also exist, although they have received less attention within a biogeographical context. Variation in flight‐related morphology has often been studied relative to landscape structure. However, the extent to which landscape effects interact with latitudinal clines of phenotypic variation has rarely been tested. Here we address the effect of latitude, landscape type and the interaction effect on body size and flight‐related morphology in the speckled wood butterfly Pararge aegeria. Male adult butterflies were collected from two replicate populations in each agricultural and woodland landscape types along a 700 km cline in six latitudinal zones. Overall size, adult body mass and wing area increased with latitude in line with Bergmann's rule. Forewing length, however, decreased with latitude. As predicted from thermoregulatory needs in ectotherms, the basal wing part was darker to the north. Latitudinal trends for flight‐related morphological traits were opposite to predictions about flight endurance under cooler conditions that were observed in some non‐lepidopteran insects, i.e. wing loading increased and wing aspect ratio decreased with latitude. Opposite trends can, however, be explained by other aspects of butterfly flight performance (i.e. mate‐location behaviour). As predicted from differences in environmental buffering in woodland landscapes along the latitudinal gradient, significant landscape×latitude interaction effects indicated stronger latitudinal clines and stronger phenotypic variation for size and flight morphology in the agricultural landscape compared to the woodland landscape. In agreement with significant interaction effects, morphological differentiation increased with latitude and was higher between population pairs of agricultural landscape than between population pairs of woodland landscape. These results demonstrate that landscape, latitude and their interaction contribute to the understanding of the complex geographic variation in P. aegeria adult phenotypes across Europe.