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1.
V. Sigurdsson G. Halldórsson A. Sigurgeirsson Æ. TH. Thórsson K. Anamthawat-Jónsson 《Agricultural and Forest Entomology》1999,1(3):157-163
1 The RAPD method (Random Amplified Polymorphic DNA) was used to investigate genetic diversity of the green spruce aphid, Elatobium abietinum Walker, a pest introduced recently to Iceland. 2 This aphid in Iceland comprised two polymorphic populations, one in the east and the other in the west of the country. The genetic variation between sites within a population was continuous and appeared to be in good agreement with geographical distances. 3 In the eastern population the variation was greater between sites than within sites, whereas in the western population the pattern of variation appeared to be the opposite. This overall greater genetic variation in the eastern population could be due to its having been colonized earlier than the western one. 4 The study also demonstrated a close relationship between the green spruce aphid in Iceland and aphids from Denmark, which agrees with their assumed origin. The differences in introduction time, adaptation and competitiveness between the two Icelandic populations are discussed. 相似文献
2.
Premature abscission of older Sitka spruce foliage on trees within forests in Northern Ireland was compared with green spruce aphid population levels 2 to 3 months earlier. Each aphid has a lower relative impact on needle loss at higher aphid population density; nevertheless, more aphids on a tree results in greater rates of needle loss. Evidence from horizontal stem increment sequences suggested that aphid feeding inhibited incremental growth, and that this inhibition might be delayed for up to two field seasons. However, the effect of aphids on stem growth in most years and on most trees seems relatively small compared with the potential of other tree-or year-specific processes. 相似文献
3.
1 Green spruce aphid (Elatobium abietinum) is a serious pest of spruce (Picea spp.) in north‐west Europe, causing defoliation of one‐year‐old and older needles. 2 Relationships between population development of E. abietinum, needle loss and tree growth were compared for five pure genotypes of Sitka spruce and mixed‐genotype material of Sitka and Norway spruce, grown under high and low nutrient conditions. 3 Despite wide differences in flushing date between spruce genotypes, E. abietinum populations peaked on the same date on each genotype and on the mixed‐genotype material, irrespective of nutrient supply. 4 Larger aphid populations developed on trees grown under high nutrient conditions than under low nutrients. However, more needles were lost per aphid in the low nutrient treatment and overall defoliation rates in the two nutrient treatments were similar. 5 Total aphid numbers differed significantly between Sitka spruce genotypes within nutrient treatments, but not in relation to bud‐burst or needle terpene content. Reductions in height growth caused by infestation were greater (15–44%), and related to mean aphid densities and defoliation, in the low nutrient treatment, but were smaller (11–27%) and not related to aphid density and defoliation in the high nutrient treatment. 6 Development of E. abietinum populations was similar on Norway and Sitka spruce, but Norway spruce lost fewer needles. However, the effects of infestation on tree growth were more closely related to aphid density and were similar for Norway and Sitka spruce. 7 Infestation caused a decrease in total root dry weight of Norway and Sitka spruce in proportion to the reductions observed in above‐ground growth. 相似文献
4.
Nigel Straw Nick Fielding Gill Green John Price 《Agricultural and Forest Entomology》2006,8(2):139-154
1 Seasonal changes in the distribution of green spruce aphid Elatobium abietinum (Walker) within the canopy of 20–25‐year‐old Sitka spruce are described based on data from two low‐altitude sites (310–420 m above sea‐level), two mid‐altitude sites (500–550 m a.s.l) and one high‐altitude site (610 m a.s.l). 2 Aphids were counted throughout the canopy on shoots representative of all needle age‐classes present at each whorl of branches. Counts were made during the middle week of each month from September to July for 4 years (1999–2003), and mean E. abietinum densities at each canopy position were calculated separately for each month and for the low‐, mid‐ and high‐altitude sites. 3 During September to November, the highest densities of E. abietinum occurred on 3–4‐year‐old needles on branches low in the canopy. Over the winter and spring, the centre of the aphid’s distribution shifted outward and upward, so that by June of the next year the highest aphid densities occurred on current and 1‐year‐old needles on branches near the top of the tree. 4 The aphid distribution was re‐set each year during July, at the time when the nutrient quality of the host was in decline and E. abietinum populations were decreasing. Aphid densities decreased less on 3–4‐year‐old needles than on current and 1‐year‐old needles, suggesting that older needles were a superior food resource at this time of year and in the autumn. However, other factors, such as higher temperatures in the upper canopy during the summer or differential mortality caused by natural enemies, could also have contributed to the change in distribution. 5 The outward and upward shift in the aphid distribution over the winter period provided no evidence that aphids at positions lower and deeper in the canopy were better insulated from freezing temperatures and had higher over‐winter survival rates. Mean air temperatures at the top and bottom of the canopy during the winter were also found to differ by only 0.1–0.2 °C. 6 The percentage of the total aphids per tree that occurred on current or 1‐year‐old needles varied widely between seasons and between sites. Consequently, sampling programmes designed to estimate total population numbers of E. abietinum have little option but to sample needles throughout the canopy, and at regular intervals during the period when the aphid is abundant. 相似文献
5.
Abstract 1 The green spruce aphid, Elatobium abietinum, is an important defoliator of Sitka spruce in the U.K. However, it is usual for years in which high E. abietinum populations occur to be followed by a year with low aphid densities. The possibility that the performance of E. abietinum is reduced on previously infested Sitka spruce, and that this is the cause of year‐to‐year fluctuations in population density, was investigated by comparing population development and the growth rate of individual aphids on experimentally defoliated trees. 2 Separate experiments were performed to determine whether aphid performance was reduced either in the autumn immediately after defoliation in the spring, or was reduced in the spring of the next year. Different rates of initial defoliation on trees used to test aphid performance were created by artificially infesting the trees with aphids in the spring before the experiments, and varying the time of infestation. 3 Population development and the mean relative growth rate (MRGR) of individual aphids on previously defoliated and undefoliated Sitka spruce did not differ significantly in the spring of the next year. No differences were observed in the nutrient content of the 1‐year‐old needles of previously defoliated or undefoliated trees at this time. 4 In the autumn and winter immediately after spring defoliation, aphid MRGR was significantly higher on trees that had been heavily defoliated earlier in the season compared with trees that had been lightly defoliated. However, the difference in MRGR decreased over the winter period. Nitrogen, phosphorous and potassium concentrations were 9.4–12.2% higher, at the beginning of the autumn, in the current year needles of heavily defoliated trees than in the current year needles of lightly defoliated trees. 5 The experiments indicate that high populations of E. abietinum in the spring do not induce any defensive mechanisms in Sitka spruce that adversely affect subsequent generations of the aphid. By contrast, the results suggest that high spring densities of the aphid improve the nutritional quality of the current year's foliage for autumn generations. 相似文献
6.
Abstract 1 The susceptibility of different genotypes of 29‐year‐old Sitka spruce to damage by the green spruce aphid, Elatobium abietinum, was investigated in a progeny trial where aphid damage on individual trees had previously been assessed twice in an earlier stage of ontogenetic development. The progeny trial comprised 14 open‐pollinated families originating from a clonal seed orchard that had been established using mature spruce trees selected for aphid resistance. 2 Previous investigations had demonstrated that resistance was inherited by the offspring, and that differences in resistance between progenies of the individual orchard clones were highly significant. 3 Susceptibility to aphid attack was recorded as the percentage loss of previous year's needles. Differences in susceptibility recorded between the juvenile trees were found to persist after the trees had developed into the closed‐canopy, sexually reproducing stage. Needle loss of the families was significantly less than that of the reference population of Sitka spruce. 4 Hybrids between Sitka spruce and white spruce were defoliated more heavily than pure Sitka spruce, and the difference increased with age. 5 Family heritability of resistance was estimated as 0.60 compared to 0.73 when the trees were assessed in the juvenile stage. The genetic correlation based on family means between damage in the juvenile and sexually reproducing stand was high (0.83), indicating a high consistency of resistance to the aphid over years and ontogenetic stages. 6 A skewed distribution of defoliation indicated that major genes are involved in the expression of resistance, and that the genetics behind resistance has a nonadditive component. 相似文献
7.
Abstract. 1. Current evidence suggests that seasonal changes in spruce needle sap nutrients have a decisive influence on green spruce aphid ( Elatobium abietinum ) population density, but the mechanisms of population change, the roles of development rate, fertility and mortality, and the existence of density-dependent processes, are not clearly understood.
2. Experimental studies of aphid populations were conducted in controlled environments to estimate seasonal patterns in aphid mean relative growth rate, prenatal development, fertility, and mortality. Studies were also made of the effect of aphid crowding on vital rates.
3. Independent of the degree of aphid crowding, seasonal changes in the amino acid concentration of needle sap were tracked by aphid growth rate, fertility (and adult size), but not by rates of aphid mortality. The most pronounced change in vital rates, and the one most likely to drive seasonal population change, was in fertility. Prenatal development time actually became shorter in periods when nutrients were scarce, but the resulting adult aphids were smaller and less fertile than during periods of improved nutrition.
4. Density dependence of vital rates was only observed during mid-summer when nutrients were least available. Mortality, growth rate, and prenatal development were the most strongly density-dependent processes. In contrast, there was no evidence that fertility rates were likely to respond to crowding.
5. There were no important differences between populations reared on small, potted spruce trees and those on plantation trees aged 25 years. This gives confidence that demographic data from a variety of field and laboratory sources could be used to compile data appropriate for population models. 相似文献
2. Experimental studies of aphid populations were conducted in controlled environments to estimate seasonal patterns in aphid mean relative growth rate, prenatal development, fertility, and mortality. Studies were also made of the effect of aphid crowding on vital rates.
3. Independent of the degree of aphid crowding, seasonal changes in the amino acid concentration of needle sap were tracked by aphid growth rate, fertility (and adult size), but not by rates of aphid mortality. The most pronounced change in vital rates, and the one most likely to drive seasonal population change, was in fertility. Prenatal development time actually became shorter in periods when nutrients were scarce, but the resulting adult aphids were smaller and less fertile than during periods of improved nutrition.
4. Density dependence of vital rates was only observed during mid-summer when nutrients were least available. Mortality, growth rate, and prenatal development were the most strongly density-dependent processes. In contrast, there was no evidence that fertility rates were likely to respond to crowding.
5. There were no important differences between populations reared on small, potted spruce trees and those on plantation trees aged 25 years. This gives confidence that demographic data from a variety of field and laboratory sources could be used to compile data appropriate for population models. 相似文献
8.
Guy Lemperiere Keith R. Day Yves Petit-Berghem Nicolas Robinet Pérrine Portier Simon R. Leather Damien Marage 《The Annals of applied biology》2020,176(3):233-240
The hypothesis that similar processes govern interannual dynamics of green spruce aphid in the UK and France, is generally supported by the application of a general discrete model. A simple model based on relatively few parameters was able to closely characterise interannual population dynamics from completely independent aerial and arboreal samples of aphids. Long-term field population estimates of the green spruce aphid Elatobium abietinum (Walker) in France have provided the opportunity to select and evaluate the generality of a model, which was developed in the UK to explain the year-to-year variations in peak abundance of the aphid. The objective was to observe the influence of the local climates and disturbing climate factors on the population densities of the insect in two regions of France. The model uses climate variables and aphid population data from regular samples in the two regions that were investigated. A general discrete model was used to predict aphid population densities. The model performed well in tracking the interannual patterns of population but was less likely to predict absolute population density. To improve predictions, further account would need to be taken of additional site-specific climate variables and the strength of overcompensating density dependence. Nevertheless, it is clear that broadly similar processes are at work in the population dynamics of this insect across its biogeographical range. 相似文献
9.
The green spruce aphid, Elatobium abietinum, is the most important defoliating pest of Sitka spruce, Picea sitchensis, in the UK. Populations are expected to increase in response to predicted climate change, therefore placing Sitka spruce under increased risk of widespread and severe defoliation. The effect of spring–summer drought stress on E. abietinum population dynamics and development over multiple years was assessed in a field experiment under five different drought treatments with differing intensities and frequencies. The impact on host tolerance, in terms of needle retention, was also investigated. No differences in the length of time taken to reach peak population size were observed. Despite this, E. abietinum populations were found to respond positively to low amplitude intermittent stress, with high densities maintained for longer after the peak. Spring peak densities of aphids did not differ among drought levels, although an autumn peak was observed consistently over 2 years on trees subjected to continuous severe drought. This suggested advancement in the onset of Sitka spruce dormancy. Aphid infestation significantly increased percentage needle loss under all drought treatments, although no differences were observed between drought levels. An interaction between aphid presence and drought treatment was, however, observed during a second year of drought where no aphids were present. The study herein presented has contributed to the understanding of E. abietinum population responses under a changing climate. The implications for damage to host Sitka spruce are of relevance to forest management strategies, as an increase in drought events are predicted in the UK. 相似文献
10.
Keith Richard Day Matthew P. Ayres Richard Harrington Neil A. C. Kidd 《Population Ecology》2010,52(2):317-327
Partial defoliation of spruce by the green spruce aphid Elatobium abietinum (Walker) is a recurrent event in European and, increasingly, North American forests. The patterns of insect abundance on trees have never been satisfactorily described by a numerical model despite considerable knowledge of endogenous and exogenous factors in the population dynamics of the species. Long-term field population estimates of the aphid on foliage provided the opportunity to evaluate such a model. Unlike comparable models for tree-dwelling aphids, this was also applicable to almost completely independent aphid field data derived from the Rothamsted Insect Survey’s nationwide network of suction traps. Although based on relatively few parameters, the model was robust in its predictions of alate aphids geographically remote from the forest in which the original population was estimated. The population maximum, which causes the greatest forest damage, is reached in early summer and can be predicted from knowledge of winter temperature (chill bouts), spring temperature (thermal sum), and interannual negative feedback (density dependence). The model provides confirmation that alate populations of spruce aphids, upon which a number of other extensive studies have been based, are ultimately influenced by similar endogenous and climatic factors and that they are a reasonable proxy for aphids on trees. 相似文献
11.
- The most important defoliating pest of Sitka spruce Picea sitchensis in the U.K. is the green spruce aphid Elatobium abietinum. This aphid species is expected to respond to a predicted increase in the incidence of spring–summer drought events, with serious implications for growth of infested spruce plants and control of the pest.
- Growth rate, adult weight and nymph weight of E. abietinum were assessed under controlled laboratory conditions, using five levels of spring–summer drought of differing intensities and frequencies. Trials were time‐staggered to investigate changes through season.
- Growth rate, adult weight and nymph weight were consistently increased under low amplitude intermittent drought stress, suggesting improved host nutritional quality through the year and increased fecundity.
- A complex response under severe and low amplitude intermittent drought stress was also observed, mediated by season. Although an overall reduction in host quality was typically observed, continuous severe stress improved host quality during the autumn. Despite this, the onset of dormancy was unaffected.
- The findings of the present study have implications for E. abietinum population development, Sitka spruce growth and biological control of the species under climate change and increased drought frequency.
12.
Simon R. Leather 《Agricultural and Forest Entomology》2015,17(3):309-316
- Elatobium abietinum (Walker) is the most important defoliating pest of Sitka spruce Picea sitchensis (Bong.) Carr. Climate change in the U.K. is predicted to increase incidences of spring–summer drought events, with the aphid expected to respond to these changes. This will have serious implications for damage levels and growth of infested Sitka spruce, as well as control of the aphid pest.
- Under controlled laboratory conditions, nymphal survival rate, lifespan and generation time of E. abietinum were examined in time‐staggered trials during the spring and autumn periods of population growth, using five levels of drought with differing frequencies and magnitude.
- Survivorship and lifespan were unaffected by drought stress compared with a well‐watered control. Generation time, however, was increased under severe continuous and high amplitude intermittent drought stress. Advancement of Sitka spruce dormancy was not supported as no differences between the autumn trials were observed for the three parameters.
- The findings of the present study suggest that, under severe water deficit, populations of E. abietinum may be reduced as a result of a reduced period of time available for reproduction. This has implications for the population development of E. abietinum and, consequently, damage levels and growth reductions of host Sitka spruce under altered climatic conditions.
13.
14.
苹果属小金海棠的遗传多样性初步研究 总被引：9，自引：0，他引：9
用RAPD技术建立了苹果属小金海棠（Malus xiaojinensis）2个自然分布区的3个群体内随机选取的30株树（10株／每群体）及其相应的子代实生苗共6个群体、60个样本植株的分子标记。通过对15个3承机引物产生的81条RAPD这的统计,计算了不同群体RAPD多态性带的数目。用TREECON软件分析了不同群体及所有个体间的遗传关系,并用AMOVA技术分析了物种的遗传变异。结果是15个引物在全部分析个体中产生了58条多态性带,平均每引物3.8条。现有分布3个群体及其相应的子代实生苗群体的平均多态性带的数目都为1.5条左右。其中平均多态性带的数目最低的群体仅有0.7条,最高的群体也只有2.5条。遗传关系分析表明,2个自然分布区的不同群体间存在遗传分化现象。AMOVA分析显示小金海棠的遗传变异有相当一部分来源于群体间。 相似文献
15.
Bernhard Stadler‡ Thomas Müller† Lucy Sheppard‡ Alan Crossley‡ 《Agricultural and Forest Entomology》2001,3(4):253-261
1 In a field acid mist simulation experiment, Sitka spruce (Picea sitchensis) was sprayed with different pollutant treatments: N, NH4NO3; S, Na2SO4; NS Acid, NH4NO3 + H2SO4 and control, no spray. Treatment effects on the abundance of the green spruce aphid Elatobium abietinum and honeydew production were assessed. In addition, needles were sampled for phyllosphere micro‐organisms. In a manipulative experiment, shoots were established and maintained as with or without E. abietinum infestation in order to determine the effects of infestation on needle loss and throughfall nutrient fluxes. 2 Aphid numbers were highest during the end of May and early June, with almost twice as many needles infested in the NS Acid treatment compared with the other treatments. Honeydew production was not affected by the treatments. 3 On infested shoots, increasing numbers of yellowing and dead needles were recorded above the throughfall collectors as the season progressed. The numbers of dead needles falling into the collectors were significantly higher beneath infested shoots. There were strong positive correlations between aphid numbers above the throughfall collectors, the number of yellowing and dead needles on the shoots and the number of needles in the funnels of the throughfall collectors. Litter production was more affected by aphid number than by pollutant treatment. 4 Bacteria, yeasts and filamentous fungi were more prolific on infested needles and treatment effects on colony forming units (CFUs) were most pronounced in the NS Acid treatment. 5 Fluxes of inorganic nitrogen beneath infested shoots were generally lower than beneath uninfested shoots. This effect was more pronounced in those treatments that supplied N i.e. N, NS Acid. The combination of aphid infestation and N‐addition exerted the strongest influence on nutrient fluxes. The fluxes of potassium and of organic carbon (DOC) were higher beneath infested shoots in all treatments, through most of the survey period. 相似文献
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17.
中华结缕草 (ZoysiasinicaHance.)在我国是分布于东部沿海地区的一个受威胁禾草 ,形态上还有一个分布在海边的变种 ,长花中华结缕草 (Z .sinicavar.nipponicaOhwri)。采用 1 0条随机引物对采自我国不同地区 7个居群的 1 0 5个个体进行了RAPD扩增 ,对结果的AMOVA分析表明 ,中华结缕草组间遗传分化不显著 ,遗传变异只占总变异的 4.84% ,居群间遗传变异占总遗传变异的 2 4.71 % ,出现了显著的遗传分化 ,大部分变异存在于居群内部 ,占总变异的 70 .44%。不同数据处理方法得到了类似的结果 ,都支持哈迪 -温伯格平衡的假设。其中宁国汪溪居群和射阳海边居群变异最大 ,歙县新安江居群遗传变异最小。考虑到中华结缕草遗传结构和变异的这些特性 ,在取样策略、保护和育种方法上 ,都应该以群居为主 ,同时兼顾主要的异地居群 相似文献
18.
对松嫩草原上分布的灰绿型和黄绿型羊草9个种群进行了15个引物的RAPD分析,统计结果表明,两类种群的扩增片段数和多态位点比率明显不同,黄绿型种群低于灰绿型,其值分别＜90与＞100,＜50％与＞70％,比较了7种不同统计方法据RAPD表型或基因型频率估算的种群遗传多样性,几种统计结果都揭示,黄绿型种群低于灰绿型种群,用F1s值矫正种群对Hardy-Weinberg平衡的偏离后,估算等位基因频率,通过Shannon指数和Nei指数估计羊草种群间分化分别为37．6％和35．7％,高于等位酶的分析,讨论比较了等位酶和RAPD分析结果的异同。 相似文献
19.
CHRISTOPH REISCH 《Botanical journal of the Linnean Society. Linnean Society of London》2004,145(1):109-117
The present study focuses on the genetic differentiation between six coexisting species of Taraxacum sect. Erythrosperma . Twenty-six individuals of T. rubicundum , T. brachyglossum , T. tortilobum , T. lacistophyllum , T. parnassicum and T. scanicum were sampled at 14 locations in south-east (Bavaria) and west Germany (Eifel). Using random amplified polymorphic DNA (RAPD) analysis 139 fragments were amplified. Nineteen of these were found to be species specific. The level of polymorphic bands within the different Taraxacum species varied between 0% and 15.8%. An analysis of molecular variance (AMOVA) revealed strong differentiation between the investigated species: 14.3% of the molecular variance were found within the species, while 85.7% of the genetic variability was observed between the species. However, a geographical differentiation between the different regions could not be observed. All analysed species were clearly separated from each other in a cluster analysis using the neighbour joining technique. The observed strong genetic differentiation between the Taraxacum species clearly supports the agamospecies concept of Taraxacum sect. Erythrosperma , which is at present mainly based on morphological and cytological criteria © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 145 , 109–117. 相似文献
20.
小麦异交群体选择分化的RAPD分析 总被引：3，自引：1，他引：2
用RAPD分子标记技术及数量遗传分析手段对小麦异交群体趋异选择4代得到的各子群体的遗传关系进行了分析,并对两种结果进行了相关分析。采用11个引物扩增出134个位点,RAPD分析结果表明,群体具有丰富的遗传变异,整个群体的多态位点百分率达0.8134,杂合度达0.3006;子群体间遗传分化较小,相对基因分化系数Gst为0.2310,固定指数平均0.2120,标准遗传距离为0.1044±0.048,表明遗传变异多数来自群体之内。而数量遗传分析发现,选择性状进展都与预期方向相符,主成分遗传距离大部分达显著水平,说明选择使群体发生了相当程度的分化。对两种遗传距离进行聚类分析表明,二种信息间关系各类群成员多不一致。其原因可能在于：数量性状是人工选择的目标,RAPD是基因组随机序列的扩增,二者之间的相关与引物选择有关。Abstract：The genetic relations of some subpopulations in the fourth generation of selection in outbreeding population of winter wheat were examined by RAPD techniques and quantitative analysis. The correlations of the two results were examined.For RAPD analysis, 11 primers were adopted, and 134 sites were amplified. The results showed that abundant genetic variations existed in the populations. In the whole population, the percentage of polymorphic sites (P) is 0.8134, and the averaged heterozygosity is 0.3006. However,genetic differentiation among subpopulations is small. The relative gene differentiation (Gst) is 0.2310,fixed index averages 0.2120, and the standard genetic distance between subpopulations is 0.1044±0.048.All above shows that most of the genetic variations existed within populations.The cluster results from RAPD analysis and principal component distances showed that similarity relations were only found in small part of the subpopulations. The reason for the results may be that the genes concerned for quantitative traits are selected directly,while the genes involved in RAPD analysis are only random samples of the whole genomes. 相似文献