始红蝽越冬聚集行为对其能量代谢的影响

聚集行为是动物适应不良环境的一种生态对策。始红蝽Pyrrhocoris apterus在成虫滞育越冬期间具有显著的聚集行为。采用LI-6400型光合仪测定了5种聚集度(分别用1头、5头、10头、20头和50头的群体大小表示)下始红蝽的呼吸量,通过呼吸量计算得到各聚集度始红蝽的呼吸速率(rate of respiration,Rr)及能量代谢速率(rate of metabolism,Rm),旨在明确聚集行为是否能够对始红蝽越冬时的能量代谢产生影响。结果表明： 不同聚集度间始红蝽的Rm值存在显著性差异; 并且随聚集度的增加,Rm值与聚集度呈显著负相关,Rm值依次为0.052,0.044,0.041,0.037和0.033 W/g。结果说明聚集行为可以有效降低始红蝽新陈代谢速率,有利于种群成功越冬。     

异色瓢虫成虫耐寒能力的季节性变化

为研究异色瓢虫Harmonia axyridis自然种群耐寒能力的季节性变化,测定了其过冷却点、体内含水量及总脂肪含量和低温存活力。结果表明：异色瓢虫成虫低温存活力呈现出明显的季节性变化,越冬前成虫的耐寒性显著强于夏季成虫和越冬后成虫。冷驯化（5℃, 5 d）可以显著提高夏季成虫的低温存活力。雌雄成虫过冷却点和体内含水量随气温的降低而降低,升高而升高。过冷却点7月份最高,分别为−7.6℃和−8.0℃;越冬中期（2008-01-15）最低,分别为−18.1℃ 和−16.9℃。雌雄成虫体内含水量9月份最高,分别为66.87%和68.01%,10月份显著降低,越冬后期（2008-02-19）最低,分别为52.94%和51.53%。越冬期间过冷却点和体内含水量显著低于其他时期。而雌雄成虫体内总脂肪含量在越冬开始就达到最高,分别为50.07%和47.93%,随后又逐渐降低,越冬期间显著高于其他时期。由此可知异色瓢虫自然种群的耐寒性呈现出明显的季节性变化,文中还就异色瓢虫自然种群耐寒性影响因素及其越冬策略进行了讨论。     

异色瓢虫不同色斑型成虫的耐寒性研究

【目的】研究异色瓢虫Harmonia axyridi不同色斑型成虫的耐寒能力,以明确其色斑型比例所呈现的季节性变化的适应意义。【方法】本文测定了异色瓢虫实验种群和自然种群不同色斑型成虫的过冷却点(Supercooling point,SCP)及低温存活率。【结果】同一发育温度下异色瓢虫实验种群不同色斑型成虫的SCP和低温存活率均没有显著性差异(P>0.05),但是低温暴露中饲养在25℃下成虫的存活率下降更为剧烈。异色瓢虫自然种群黑底型与黄底型成虫的SCP呈现出明显的季节性变化,其SCP在7月份最高,分别为﹣8.2℃和﹣7.5℃;在1月份达到最低,分别为﹣16.8℃和﹣18.2℃。越冬开始(11月)黑底型成虫的SCP低于黄底型成虫的,整个越冬期间黄底型成虫的SCP一直低于黑底型成虫的,但是异色瓢虫黑底型与黄底型越冬成虫的低温存活率却没有显著性差异(P>0.05)。【结论】越冬期间异色瓢虫黄底型成虫的SCP低于黑底型的,这样可以通过体液过冷却的方式来避免结冰造成的伤害,以增强其越冬种群的耐寒能力,这也可能是越冬期间异色瓢虫黄底型成虫数量显著上升的一个原因。     

异色瓢虫对蚜虫性外激素的行为反应研究

蚜虫性外激素假荆芥内酯(Z,E-Nepetalactone,NEP)能够吸引多种捕食性和寄生性天敌昆虫,它专一性强,生物活性突出,对非靶标生物安全。异色瓢虫Harmonia axyridis(Pallas)作为一种重要的捕食性天敌,被广泛应用于农业生产中。为明确异色瓢虫对蚜虫性外激素的行为反应,本研究在室内用"Y"型嗅觉仪测定了异色瓢虫成虫对不同剂量NEP的嗅觉行为反应;并在田间,每7 d释放100μL浓度为1 mg/m L的NEP,测定了NEP对异色瓢虫种群数量变动的影响。室内嗅觉测定试验结果表明异色瓢虫雌虫对10μL剂量NEP有显著的选择性,而雄虫对1μL剂量NEP有显著的选择性;田间试验发现,释放NEP的处理区异色瓢虫数量显著高于对照区。本研究为蚜虫性外激素在害虫绿色防控中的应用提供了依据。     

异色瓢虫幼虫对卵的种内自残和种间捕食

自残现象的发生在异色瓢虫Harmonia axyridis中很是常见,为明确自残行为对其存活和生长发育的影响,在非选择性条件下我们对异色瓢虫幼虫对非姊妹卵的种内自残和对七星瓢虫Coccinella septempunctata卵的种间捕食进行了研究。结果表明,异色瓢虫取食同种卵和异种卵均可完成生长发育,与取食蚜虫相比：①其从卵到成虫及蛹期的发育历期明显缩短（P<0.05）,其中1龄幼虫发育历期缩短非常明显（P<0.01）;②自然条件下高死亡率的1龄幼虫的存活率明显提高（P<0.05）;③2-4龄幼虫、蛹和成虫的体重变轻（P<0.05）,且体长在4龄幼虫间也表现出显著差异（P<0.05）。这表明异色瓢虫种内自残和种间捕食对其在食物恶劣条件下延续种群至关重要,但对种群的繁衍却不是最理想的途径。     

温度对异色瓢虫生长发育和繁殖的影响

为探索饲养异色瓢虫Harmonia axyridis（Pallas）的最适温度,了解其对高温的耐受性,组建了异色瓢虫在15,20,25,30和35℃下的实验种群生命表。结果表明：各虫态的发育速率随温度的升高而加快,在15℃下世代的发育历期最长（65.5d）,而30℃时仅为22.4d,20℃和25℃时分别为39.0d和23.0d。卵、幼虫、蛹和世代的发育起点温度分别为9.8,8.2,11.6和8.5℃,有效积温分别为41.1,225.6,81.6,432.6日.度。成虫寿命随温度升高而逐渐缩短,15℃时最长,为77.7d,在30℃下最短,为36.3d;单雌产卵量在25℃时最高,平均为2193.0粒,15℃时最低,为626.0粒。在25℃下,异色瓢虫的种群趋势指数和内禀增长力均较高,分别为916.7和0.15,表明25℃是异色瓢虫生长、繁殖的最适温度。     

在转Bt基因棉压力下棉铃虫和异色瓢虫的波动性不对称

以取食转Bt基因棉的棉铃虫和取食转Bt基因棉上的蚜虫的异色瓢虫为研究对象,结合各自的适合度参数考察了波动性不对称（fluctuating asymmetry, FA）在不同种群中各对称性状间的表现情况。结果表明： 处理组棉铃虫种群的前、中、后足腿节,前翅肘横脉,前翅副室短径,后翅翅长均表现出FA;与对照种群比较,前足腿节与后翅翅长的FA值较高。 适合度参数测定结果显示,棉铃虫卵孵化率与成虫寿命显著低于对照种群,而成虫产卵量和幼虫发育历期与对照种群差异不显著。异色瓢虫取食了转Bt基因棉上的蚜虫后对其适合度各参数及各虫龄的捕食功能反应均无不良影响,其后翅翅长表现出FA,但与对照种群的FA值无显著差异。FA的大小与种群适合度间存在一定的联系,尚需做进一步的分析。     

长期冷藏对越冬代异色瓢虫繁殖及子代生长发育和捕食能力的影响

异色瓢虫被认为是一种重要的捕食性天敌,常被用来防治蚜虫、介壳虫、叶螨等害虫。为了更好地开发利用东北地区丰富的越冬代异色瓢虫自然资源,本研究调查了低温冷藏(3℃冷藏0,30,60,90,120,150 d)对吉林采集的越冬代异色瓢虫繁殖及其子代生长发育和捕食能力的影响。研究结果表明,经历90 d冷藏的瓢虫产卵量最大,明显高于冷藏60 d个体的产卵量,与冷藏120 d、150 d及未经冷藏个体的产卵量不存在明显差异;经历不同冷藏期的瓢虫与室内人工饲养种群子代具有相似发育历期(约16.0 d);而且长期冷藏也未对瓢虫子代幼期的捕食能力产生负面影响,冷藏150 d瓢虫的子代在整个幼虫阶段能捕食662.8头蚜虫,与未冷藏个体和人工饲养种群个体不存在明显差异。本研究为开发利用东北地区越冬代异色瓢虫自然资源的生物防治作用提供了理论依据。     

不同龄期异色瓢虫对烟蚜的捕食潜能研究

异色瓢虫是烟田烟蚜的优势天敌种类之一,本文在室内进行了异色瓢虫成虫及各龄幼虫对烟草蚜虫的捕食功能反应试验,采用Holling-Ⅱ型功能反应模型进行拟合以明确其捕食潜能,利用Hassell模型和Watt模型拟合并测定了异色瓢虫种内干扰以及自身密度对烟蚜捕食作用的影响,结果表明:异色瓢虫各虫态对烟蚜的捕食量有明显的差异,在相同的烟蚜密度条件下,异色瓢虫4龄幼虫的日最大捕食量最大,为107.41头;其次是成虫,其日最大捕食量为94.34头;3龄幼虫、2龄幼虫和1龄幼虫的日最大捕食量分别为40.32头、14.25头和12.15头。在一定空间和相同比例猎物存在的条件下,种内干扰作用对1龄异色瓢虫幼虫的捕食量影响最为明显,干扰常数为1.1731,而对4龄幼虫干扰最小。各虫态自身密度对其捕食作用的干扰效应明显,1-4龄异色瓢虫幼虫以及成虫的竞争参数b值分别为0.5199、0.1848、0.1351、0.6757、0.6528。本研究表明异色瓢虫对烟蚜捕食潜力很大,尤其是4龄幼虫及成虫对烟蚜具有较大的捕食潜能。     

稻根象甲种群空间格局及其受耕法的影响

本文根据36块田的调查,用种群空间格局参数I、C_A、I_δ、m~*/m和α、β值进行分析,稻根象甲幼虫和(?)≥0.6头/样方(每样方为0.5m~2)的成虫种群,在稻田均属具公共k值的负二项分布;(?)<0.6头/样方的成虫种群则为随机分布。成虫聚块的大小和面积与平均密度有关。低密度时种群的聚集主要由于环境的异质性;高密度时种群的聚集则由本身的行为习性所致。随着耕作强度的增加,幼虫种群的聚集度和越冬死亡率增大。     

Impact of fruit feeding on overwintering survival of the multicolored Asian lady beetle, and the ability of this insect and paper wasps to injure wine grape berries

The establishment of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), in North America has resulted in negative impacts on fruit production. We investigated the overwintering survival of H. axyridis after feeding on four diets: injured wine grape berries, 25% sucrose solution, water, and a control containing no food or water. After being exposed to these diets for 6 days, live individuals were transferred to clean plastic Petri dishes, and held at 5 ± 1 °C in growth chambers throughout the winter. Survival was recorded every month. Adult lady beetles collected during the overwintering flight in mid-October had higher survival rates than beetles collected from soybean fields in mid-August. These results suggest that an adaptation period prior to diapause increases the chances of lady beetle survival over the winter. In addition, injured wine grape berries, sugar, and water decreased beetle mortality during the overwintering months. Our results also showed that under similar conditions, females have higher survival during the winter than males. The importance of sugar and water on winter survival may drive H. axyridis adults to vineyards for feeding on wine grapes. Finally, we tested if adults of H. axyridis and the European paper wasp, Polistes dominulus Christ (Hymenoptera: Vespidae), were able to break the grape skin. Harmonia axyridis adults and paper wasps were not able to cause the primary injury to berries of Frontenac grapes under laboratory conditions. These results suggest that control of paper wasps in vineyards may not affect H. axyridis aggregations, and that H. axyridis feeding on wine grapes depends on previous injury to grape berries.     

Role of long-chain hydrocarbons in the aggregation behaviour of Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae)

The multicoloured Asian ladybirds, Harmonia axyridis (Pallas), form large aggregations inside dwellings to survive cold winters, causing annoyance to householders due to their abundance, allergenic properties and problems consequent on reflex bleeding. Flight to overwintering sites and macrosite choice of this species is well documented. H. axyridis shows a hypsotactic behaviour and a clear preference for contrasting visual elements. However, how the microsite is selected remains undocumented, although a better understanding of the factors implicated could lead to the development of new control methods for this pest. In this work, we hypothesised that non-volatile compounds are involved in the microsite choice and aggregation of this beetle. Long chain hydrocarbons were identified at aggregation sites, comprising saturated and unsaturated homologues. An aggregation bioassay was then conducted on overwintering individuals, highlighting the retention capacity of the identified compounds on the tested ladybirds. Additional investigations showed that H. axyridis males and females, originating from overwintering sites, deposit a similar blend of molecules while walking. A Y-shaped tube assay revealed that this blend is used by male and female congeners as cue allowing individuals to orientate towards the treated side of the olfactometer. These results suggest the use of two different blends of long chain hydrocarbons by H. axyridis during its aggregative period, the first one to lead conspecifics towards aggregation sites (microsites) and the second to ensure the cohesion of the aggregation. These findings support the potential use of these blends, in association with volatiles, in the design of traps in order to control infestations of this species in dwellings.     

Toxicity of commonly used insecticides in sweet corn and soybean to multicolored Asian lady beetle (Coleoptera: Coccinellidae)

Use of insecticides with low toxicity to natural enemies is an important component of conservation biological control. In this study, we evaluated the toxicity of insecticides used in sweet corn, Zea mays L., and soybean, Glycine max (L.) Merr., to the multicolored Asian lady beetle, Harmonia axyridis (Pallas), under laboratory and field conditions. Field experiments conducted in sweet corn in 2003 and 2004 and in soybean in 2003, showed that H. axyridis was the most abundant predator. In sweet corn, densities of H. axyridis larvae in plots treated with spinosad or indoxacarb were generally higher than in plots treated with chlorpyrifos, carbaryl, bifenthrin, and A-cyhalothrin. In soybean, densities of H. axyridis larvae in plots treated with chlorpyrifos were higher than in plots treated with lambda-cyhalothrin. Laboratory experiments were conducted to evaluate the acute toxicity of insecticides to eggs, first and third instars, pupae, and adults. Spinosad, followed by indoxacarb, were the least toxic insecticides for all life stages of H. axyridis. Conventional insecticides showed high toxicity to H. axyridis when applied at field rates under laboratory conditions. Overall, first instars were most susceptible to the insecticides tested, followed by third instars and adults, eggs, and pupae. Our results suggest that spinosad, and to a lesser extent indoxacarb, offer reduced toxicity to H. axyridis and would be beneficial for conservation biological control in agricultural systems where H. axyridis is abundant.     

异色瓢虫气味结合蛋白基因HaxyOBP1和HaxyOBP6的克隆及表达谱分析

【目的】本研究旨在探索异色瓢虫Harmonia axyridis气味结合蛋白的结构和分布,更好地了解气味结合蛋白在异色瓢虫嗅觉系统中的作用。【方法】利用生物信息学方法克隆异色瓢虫2个气味结合蛋白基因序列并对其蛋白结构进行分析;通过实时荧光定量PCR分析克隆获得的这2个基因在异色瓢虫各个发育阶段和成虫不同组织中的表达水平。【结果】本研究成功克隆得到异色瓢虫两个气味结合蛋白基因HaxyOBP1和HaxyOBP6(GenBank登录号分别为MG757923和MG757927)。HaxyOBP1开放阅读框全长447 bp,编码148个氨基酸,具有6个保守的半胱氨酸,表明HaxyOBP1属于Classic OBPs。HaxyOBP1在异色瓢虫各发育阶段均有表达,在雄性成虫中表达量最高;组织表达谱分析表明HaxyOBP1在雄虫头部表达量最高。HaxyOBP6开放阅读框全长414 bp,编码137个氨基酸,具有4个保守的半胱氨酸,表明HaxyOBP6属于Minus-C OBPs。HaxyOBP6在成虫期的表达量明显高于幼虫阶段,并且在雄成虫中的表达量显著高于雌成虫;组织表达谱分析表明HaxyOBP6在雄成虫头部和雌成虫翅中表达量最高。【结论】本研究克隆得到异色瓢虫两个气味结合蛋白基因,表达谱分析表明HaxyOBP1和HaxyOBP6分别在异色瓢虫成虫头和翅中具有较高的表达水平,说明气味结合蛋白基因可能在异色瓢虫非嗅觉组织中同样具有重要作用。本研究结果为深入研究异色瓢虫气味结合蛋白结构和功能奠定了基础。     

Soil respiration in poplar plantations in northern China at different forest ages

Aims

This study aims to test the effects of forest age on soil respiration in poplar ecosystems in northern China and to separate the contributions of root respiration (Rr) and soil microbes to the total soil respiration (Rs).

Methods

Rs in three poplar forests (5, 10, and 15?years old) were measured using an LI-6400-09 soil chamber connected to an LI-6400 portable infrared gas analyzer during the growing seasons in 2007 and 2008. Root respiration was measured using the root excision method. The soil micro-organisms were quantified using the dilution-plate method.

Results

The results show that Rs was the highest in the 5-year-old forest and lowest in 15-year-old forest. The contribution of Rr to Rs ranged from 29.4 to 81.0%. Rr/Rs tended to be significantly higher in the 15-year-old forest than that in the younger forests; but Rr was the highest in the 5-year-old forest. Temporal variation in Rs can be largely accounted by fine-root biomass (R?=?0.718), while soil N was significantly negatively correlated with Rs (R?=?-0.646).

Conclusions

Rs, Rr and Rr/Rs vary significantly with the forest age. The lower Rs in the older forests increased their carbon use efficiency. Underground factors, dominated by fine-root biomass, affect Rs, Rr and Rr/Rs substantially. Soil microbial community structure is a particularly important underground factor.     

海藻糖酶基因TRE2-like和TRE2在异色瓢虫羽化过程中的表达与功能

【目的】异色瓢虫Harmonia axyridis是一种重要的捕食性天敌昆虫,海藻糖在异色瓢虫的变态发育、羽化等整个生命过程都起着重要的作用。本研究以前期获得的类似膜结合型海藻糖酶(TRE2-like)与膜结合型海藻糖酶(TRE2)基因为基础,探讨在异色瓢虫羽化阶段这两个海藻糖酶的潜在功能,为阐明异色瓢虫从蛹发育到成虫时海藻糖代谢机制提供参考。【方法】根据TRE2-like和TRE2基因序列设计双链RNA(dsRNA)区域片段并合成对应的dsRNA,通过RNAi将其注射到异色瓢虫2日龄蛹中。采用实时荧光定量PCR(RT-qPCR)检测RNAi处理后羽化第1天的异色瓢虫成虫糖代谢相关基因的表达;同时采用蒽酮比色法、酶标法等分别测定RNAi处理后羽化第1天的异色瓢虫成虫主要糖类物质含量及TRE活性变化,并观察异色瓢虫羽化后的表型变化。【结果】结果表明,与对照组(dsGFP注射组)相比,异色瓢虫2日龄蛹被注射TRE2-like或TRE2 dsRNA后,其新羽化成虫体内TRE2-like和TRE2表达量均极显著下调,且少数个体出现了蜕皮与翅形成困难等畸形表型。可溶性海藻糖酶活性在注射dsTRE2-like后显著降低,膜结合型海藻糖酶活性在注射dsTRE2后显著降低;注射dsTRE2后糖原含量显著下降,注射dsTRE2-like后糖原和海藻糖含量显著下降,注射dsTRE2-like+dsTRE2后糖原和葡萄糖含量显著下降,且海藻糖含量极显著下降。注射dsTRE2-like, dsTRE2和dsTRE2-like+dsTRE2后可溶性海藻糖酶基因TRE1-1和TRE1-2表达下降或显著下降,而TRE1-5表达上升或显著上升,海藻糖合成酶(trealose-6-phosphate synthase, TPS)、糖原磷酸化酶(glycogen phosphorylase, GP)、糖原合成酶(glycogen synthase, GS)基因的表达均显著下调。【结论】TRE2-like和TRE2基因表达被抑制后,异色瓢虫海藻糖等代谢受到影响。研究结果为探究异色瓢虫体内膜结合型海藻糖酶的潜在功能和调控机制奠定了基础。     

小兴安岭4种原始红松林群落类型生长季土壤呼吸特征

为阐明小兴安岭地带性植被原始红松林土壤呼吸各组分的碳排放速率及其对土壤水热变化的响应规律,采用挖壕法和红外气体分析法测定土壤表面CO2通量(Rs),确定4种原始红松林群落类型生长季的土壤总呼吸(Rt)中土壤微生物呼吸(Rh),根系呼吸(Rr)和凋落物呼吸(Rl)的贡献量动态变化及其影响因子。结果表明:生长季内,4种原始红松林群落类型的Rt、Rh、Rr具有明显的季节性变化,7-9月份较高,6月份和10月份较低。Rh对Rt的贡献量最高,平均在58.8%;Rr对Rt的贡献量次之,平均为26.5%;Rl对Rt的贡献量相对较小,平均为12.5%。生长季土壤呼吸速率与5cm深土壤温度相关性极显著(P0.01)。Rr和Rh的Q10值分别为2.88和2.23。表明根呼吸对土壤温度的敏感性高于微生物呼吸。生长季平均土壤呼吸速率的依次为:椴树红松林(6.38μmol·m-·2s-1)云冷杉红松林(6.32μmol·m-·2s-1)枫桦红松林(5.95μmol·m-·2s-1)蒙古栎红松林(2.86μmol·m-·2s-1)。4种原始叶红松林群落类型间的Rh和Rr也存在一定差异。     

6种常用杀菌剂对苹果黄蚜及其天敌异色瓢虫的影响

本文研究了有机苹果园常用的6种杀菌剂,包括农抗120、绿乳铜、高锰酸钾、大生M-45、成标和多菌灵对果园重要害虫苹果黄蚜和h／scitricolavander Goot及其天敌异色瓢虫Harmoniaaxyridis Pallas死亡率的影响。结果表明,这6种杀菌剂使用喷雾和浸叶饲喂法对蚜虫的死亡率均有一定的影响,但校正死亡率均小于21％。喷雾处理和二次中毒处理对瓢虫幼虫的死亡率均无显著影响。上述结果说明6种供试杀菌剂的常用浓度对蚜虫有较低的致死率,而对其天敌异色瓢虫则是安全的,因此我们推测上述杀菌剂的常规使用不会对果园昆虫的群落结构造成重大影响。     

药剂处理有蚜烟叶对异色瓢虫选择行为的影响

【背景】植物挥发物的特性之一就是可变性,多种胁迫因子,如光照、干旱等,均可导致植物挥发物组分与含量发生改变,进而影响天敌搜索猎物的行为。【方法】本试验以杀虫剂作为影响植物挥发物的胁迫因子,利用“Y”形嗅觉仪观测8种杀虫剂处理有蚜烟叶后对异色瓢虫显明变种、显现变型和二斑变型选择行为的影响。【结果】异色瓢虫对健康无蚜烟叶无明显趋性;与洁净空气相比,异色瓢虫对无药剂处理有蚜烟叶的选择率为70％～74％。在氧乐果处理后,异色瓢虫显明变种、显现变型和二斑变型对有蚜烟叶的选择率分别为32％、36％和34％,氟虫腈·高氯处理后,其选择率分别为36％、38％和36％,多杀霉素处理后,其选择率分别为40％、42％和38％,异色瓢虫对这3种杀虫剂处理有蚜烟叶的趋性明显降低;吡虫啉处理后,其选择率分别为64％、62％和60％,啶虫脒处理后,其选择率分别为62％、68％和66％,这2种杀虫剂可略微降低瓢虫的趋性反应;氯氰菊酯处理后,其选择率分别为80％、82％和80％,氯氟氰菊酯处理后,其选择率均为78％,氟氯氰菊酯处理后,其选择率分别为76％、78％和76％,这3种杀虫剂可增强瓢虫的趋性反应。【结论与意义】杀虫剂可能会对烟草挥发物的组分和含量产生影响,但不同的杀虫剂影响效果不同。