云南松林两种切梢小蠹成虫蛀梢期的空间分布格局

【目的】云南松Pinus yunnanensis Faranch是我国西南地区的重要造林绿化树种。近年来,云南省祥云县云南松林受到云南切梢小蠹Tomicus yunnanensis KirkendallFaccoli和横坑切梢小蠹Tomicus minor Hartig的共同危害。本文对两种害虫在蛀梢期的危害特性和空间分布进行了研究,以期为切梢小蠹的发生监测及防治提供依据。【方法】利用地统计学方法分析不同受害程度云南松林内两种切梢小蠹成虫蛀梢期的空间分布特性。【结果】受害程度不同的云南松林内两种切梢小蠹的危害差异显著,轻度受害林分内受害梢率为11.38%,中度受害林分内受害梢率为36.56%,而重度受害林分则达到59.7%。分析全方向的变异函数曲线图得知,蛀梢期两种切梢小蠹在不同受害云南松林中均呈聚集分布。其中,两种切梢小蠹在不同受害林分中空间依赖范围依次是:轻度受害林分中度受害林分重度受害林分,而局部空间连续性依次是:轻度受害林分中度受害林分重度受害林分。【结论】云南松林两种切梢小蠹成虫在蛀梢期的空间分布格局为聚集分布,明确两者在该时期存在聚集危害的特性,导致云南松因树梢受到聚集危害变为衰落木,从而有利于成虫蛀干危害和繁殖。本文为探究两种切梢小蠹在云南松林中的危害机制提供理论基础,也为虫害监测及防治提供参考与技术支持。     

两种切梢小蠹危害云南松的时空生态位

【目的】云南切梢小蠹Tomicus yunnanensis KirkendallFaccoli和横坑切梢小蠹Tomicus minor(Hartig)是中国云南地区两种危害松属Pinus L.植物的钻蛀性害虫,常在云南松Pinus yunnanensis Faranch.上共同危害,通过蛀梢和蛀干为害造成树木衰弱死亡,生态破坏,带来经济损失。【方法】通过样地调查和树木解析,对两种小蠹在"梢转干"及"干转梢"时期的时间和空间生态位进行了研究。【结果】"梢转干"时期之后,横坑切梢小蠹主要分布在主干中下部,云南切梢小蠹分布在主干中上部;侧枝上主要分布着云南切梢小蠹,而横坑切梢小蠹数量很少;5月中旬进入"干转梢"阶段,两种小蠹同时进入羽化期,云南切梢小蠹在6月1日左右到达羽化高峰期,横坑切梢小蠹则比其晚10 d左右到达羽化高峰期;两种小蠹成虫转梢危害后随机分布。两种小蠹的时间和空间生态位宽度均较大,发生期较长,在云南松上分布范围较广。两种小蠹空间生态位重叠较小,在云南松上的分布趋于分离,对空间资源的需求具有较大差异;而时间生态位重叠较大,在云南松的生长季节能同时危害,且发生期较一致,危害期长。【结论】两种小蠹在空间生态位上的种间竞争强度较小,而在时间生态位上的竞争较大。通过研究比较两种切梢小蠹时间及空间生态位的特性及差异,为遥感监测云南松林的生物灾害提供了支撑依据。     

云南横坑切梢小蠹生物学研究

横坑切梢小蠹Tomicus minor (Hartig)是云南松Pinus yunnanensis Franchet的主要次期性害虫之一。1980年以来,该虫与纵坑切梢小蠹T. piniperda（L.）一起在中国西南部大量发生,导致数十万公顷云南松林受害。本文报道了横坑切梢小蠹在云南地区的生活史、生长、发育、繁殖等生物学特征。横坑切梢小蠹年生活史为一代,前后两代在冬春季有部分重叠。成虫羽化于4月下旬开始陆续,5 月下旬结束。成虫羽化后即飞到树冠上蛀食枝梢,直到11月发育成熟,开始繁殖。在此期间,每头成虫可以蛀食4～6个枝梢。横坑切梢小蠹在云南没有越冬习性。繁殖期从11月至次年3月。成虫主要在已经受到纵坑切梢小蠹危害的树木的中、下部产卵。繁殖期较纵坑切梢小蠹约迟1周。由于横坑切梢小蠹从枝梢到树干对云南松持续危害,对树木的危害性较在其它地区更为严重。横坑切梢小蠹利用受到纵坑切梢小蠹蛀害的树木繁殖产卵,加强了蠹虫对云南松树的危害,加速了受害树木的死亡进程。横坑切梢小蠹的上述生物生态学特征是该虫对云南松造成严重危害的重要原因。从横坑切梢小蠹虫体和虫坑中检测到伴生真菌云南半帚孢Leptographium yunnanensis。横坑切梢小蠹对该菌的带菌率在蛀梢期为11.5%;在蛀干中期约为10%～26%。     

云南松树冠受害表征与有害生物复合危害的关系

【目的】云南松Pinus yunnanensis Franch是我国西南地区重要的生态林造林树种之一。钻蛀性害虫松墨天牛Monochamus alternatus Hope、几种切梢小蠹Tomicus spp.、微红梢斑螟Dioryctria rubella Hampson和一种病害松针褐斑病Lecanosticta acicola能在云南松人工林内严重发生,对森林健康构成威胁。本研究选取树冠枯梢率作为云南松树势的评价标准,筛选出引起树冠枯梢的主要因子,建立云南松树冠受害表征与不同种类(数量)有害生物复合危害之间的关系,以期探索对云南松有害生物进行遥感监测预警的精准判别方法。【方法】设置标准地,抽样选择35株受害状为局部枝梢枯萎和29株系统性萎蔫的云南松,分别调查其上有害生物的种类和数量。使用Pearson相关性分析等方法研究云南松枯梢率与各致害因子(松墨天牛、切梢小蠹、微红梢斑螟和松针褐斑病)之间的关系。通过多元线性逐步回归的方法,筛选出导致云南松树冠局部枯梢的主要因子,建立枯梢率关于主要有害生物种群数量的反演模型。【结果】局部枝梢枯萎植株的树冠枯梢率与两种切梢小蠹的种群数量均呈高度正相关,与树木胸径和其他致害因子呈较弱或无相关性。分析标准地每木调查结果发现,树冠有无病梢不能显著影响枯梢率情况。建立了通过枯梢率(Y)反演云南松树冠两种切梢小蠹混合种群数量(X)的回归模型:Y=12.0984+0.9835 X,Adj-R2=0.8081。明确了在蛀梢阶段,云南松树势随着切梢小蠹种群数量上升而下降。在蛀干阶段,切梢小蠹和松墨天牛的钻蛀活动主要集中在濒死木和枯立木上。【结论】引起树冠局部枯梢、树势下降的主要因子为横坑切梢小蠹和云南切梢小蠹成虫的蛀梢活动;引起树冠系统性萎蔫、树木死亡的主要原因是松墨天牛与切梢小蠹的蛀干活动。应用本研究模型可通过判别云南松树冠枯梢率估算两种切梢小蠹在蛀梢期的混合种群数量,为航天遥感或无人机监测虫情提供可靠的理论基础。     

纵坑切梢小蠹对云南松蛀害研究

在昆明地区,纵坑切梢小蠹Tomicus piniperda L.表现出枝梢聚集、树干蛀害等重要的行为学特征,形成三种基本蛀害模式。横坑切梢小蠹、蓝色伴生真菌参与了纵坑切梢小蠹危害过程,并在其中发挥积极作用。上述因素的综合影响,加强了纵坑切梢小蠹对云南松Pinus yunnanensis寄主树木的危害能力。     

纵坑切梢小蠹对云南松蛀害研究

在昆明地区,纵坑切梢小蠹Tomicus piniperda L.表现出枝梢聚集、树干蛀害等重要的行为学特征,形成三种基本蛀害模式。横坑切梢小蠹、蓝色伴生真菌参与了纵坑切梢小蠹危害过程,并在其中发挥积极作用。上述因素的综合影响,加强了纵坑切梢小蠹对云南松Pinus yunnanensis寄主树木的危害能力。     

云南切梢小蠹对云南松树的蛀干危害及致死机理

蛀干危害是云南切梢小蠹致死云南松树的关键环节。通过控制云南切梢小蠹蛀干密度,对云南切梢小蠹在自然条件下蛀干行为与危害进行了首次探讨。结果表明,云南切梢小蠹蛀干密度与云南松存活率呈负相关,蛀干密度直接决定云南松死亡或存活。研究发现,蛀干密度115坑/m2是云南松树的最低致死密度阈值,云南松树在蛀干密度低于26.4坑/m2情况下存活,在26.4-115坑/m2有部分存活,超过115坑/m2以后将被害致死。云南切梢小蠹对树干攻击形成有卵和无卵两类坑道。形成无卵坑道的蛀干攻击可导致树势衰弱,形成有卵坑道的蛀干危害严重破坏了韧皮组织,是导致云南松死亡的直接原因。     

纵坑切梢小蠹蛀梢期空间分布

在昆明地区,纵坑切梢小蠹(Tomicus piniperda)成虫蛀梢多集中在蛀干木附近。 种群密度以蛀干木为中心向周围呈指数递减,散布半径约30m。在蛀梢过程中,该种群逐渐向新区扩张。在树冠内,纵坑切梢小蠹主要分布在4-10轮枝上。第7轮枝虫口百分率最高。6-7轮枝受害率最大。 树冠上层受害较其下层严重。从树冠水平层次考察,树冠外层虫量相对集中,约为树冠中、内层虫量之和。 树冠内层虫量最少。纵坑切梢小蠹在树冠内的种群分布系由梢径、种群密度、蛀梢行为、降落方式、光照等因素综合影响的结果。     

纵坑切梢小蠹蛀梢期空间分布

在昆明地区,纵坑切梢小蠹（Ｔｏｍｉｃｕｓ　ｐｉｎｉｐｅｒｄａ）成虫蛀梢多集中在蛀干木附近。种群密度以蛀干木为中心向周围是指数递减,散布半径约３０ｍ。在蛀虹梢过程中,该种群逐渐向新区扩张。在树冠内,纵坑切梢小蠹主要分布在４—１０轮枝上。第７轮技虫口百分率最高。６—７轮枝受害率最大。树冠上层受害较其下属于重。从树冠水平层次考察,树冠外层虫量相对集中,约为树冠中、内层虫量之和。树冠内层虫量最少。纵坑切梢小蠹在树冠内的种群分布系由梢径、种群密度、蛀梢行为、降落方式、光照等因素综合影响的结果。     

红外热成像监测云南松切梢小蠹虫害:针叶尺度观测

为寻求基于红外热成像技术监测云南松切梢小蠹(Tomicusyunnanensis)危害的可行性,该研究以不同受害程度的云南松(Pinusyunnanesis)针叶为研究对象,利用红外热成像仪观测受云南松切梢小蠹危害的云南松针叶温度的日变化规律,并通过不同受害程度针叶的叶绿素含量、叶片含水量以及净光合速率(P_n)、气孔导度(G_s)、蒸腾速率(T_r)等生理生化因子来分析解释针叶温度的变化。结果表明:(1)云南松针叶内叶绿素和水分含量随受害时间增加逐渐降低,叶绿素含量下降速率比含水量下降速率快;(2)叶片的P_n、G_s及T_r随受害程度增加而降低,针叶温度与大气温度的温差(ΔT_(l-a))则随受害程度增加而变大;(3)不同程度受害针叶温度与健康针叶的温差(ΔT)在14:00–15:00之间达到最大,轻度、中度和重度受害针叶ΔT分别可达0.6、0.7、2.5℃;(4)不同程度受害针叶的G_s、叶片含水量与ΔT呈较强的负相关关系。针叶受害后叶片内部水分失衡引起叶温变化,利用红外热辐射对于温度变化的敏感性,可通过红外热成像技术精确探测针叶温度的变化,从而检测到云南松遭受云南松切梢小蠹危害的程度。     

褐梗天牛幼虫和成虫空间分布的地统计学研究

褐梗天牛(Arhopalus rusticus Linnaeus)是一种对松、杉、柏等林木危害非常严重的蛀干害虫,主要危害针叶树的衰弱木以及火灾后的枯立木,是继松褐天牛之后携带拟松材线虫能力最强的蛀干害虫。为了更好地控制其危害,深入地研究其种群空间格局,运用地统计学方法分析了3块受害程度不同的油松林内褐梗天牛幼虫和成虫的空间分布特性。结果表明:3种受害程度不同的林分内,褐梗天牛的危害具有显著差异,轻度受害林分内有虫株率为30.8%,中度受害林分内有虫株率为44.3%,而重度受害林分内高达78.3%。根据变异函数曲线图分析得知:轻度受害林、中度受害林和重度受害林内褐梗天牛幼虫种群空间分布最优拟合模型分别为高斯模型、高斯模型和指数模型,成虫的种群空间分布最优拟合模型均为线性模型。在3种林分中褐梗天牛幼虫数量具有明显的空间依赖性,轻度受害林、中度受害林和重度受害林内幼虫数量的空间依赖范围分别是19.10、11.97、61.98m,其空间连续性强度分别是0.646、0.784和0.500;成虫的空间依赖范围分别是43.08、43.23、44.17m,其空间连续性强度分别是0.044、0.021和0.171,但其成虫的数量在空间呈随机分布,没有表现出空间依赖性。根据垂直分布图分析得出:褐梗天牛幼虫和成虫在油松上主要集中聚集在某个高,然后随着高度增加密度降低,随着高度接近地面密度也降低。用Kriging插值法生成的空间分布图显示幼虫在空间分布上具有明显的聚集性,其聚集中心主要集中在林地中心,由林地中心株向整个林地扩散,而成虫则表现为随机分布。     

不同林分白蜡树云斑白条天牛种群空间格局地统计学分析

云斑白条天牛是我国重要林业害虫,在黄河三角洲地区对白蜡树造成严重危害。利用地统计学方法,通过调查城市行道绿化林、庭院绿化林、公路林和片林4种不同林分类型的白蜡树林地,以产卵刻槽、排粪孔和羽化孔为调查指标,对危害白蜡云斑白条天牛种群卵、幼虫、成虫(蛹)的空间格局进行了研究。结果表明:除片林样点成虫(蛹)的半变异函数模型为指数模型外,危害白蜡云斑白条天牛种群卵、幼虫、成虫(蛹)在不同林分类型下的半变异函数模型均为球形模型,其指明空间分布均为聚集分布,种群的聚集分布习性与林分类型相关性不强。但不同林分类型云斑白条天牛种群的空间相关性地统计学参数存在差异,片林调查样点的卵、幼虫和成虫(蛹)的变程a、块金值C0和基台值C0+C均小于其他3种林分类型的统计值,片林样点成虫(蛹)的半变异函数模型不同于其他林分类型为指数模型。     

Biocontrol of Sclerotinia lettuce drop by Coniothyrium minitans and Trichoderma hamatum

Fungal isolates, with known activity against Sclerotinia spp. in laboratory assays, were tested for their ability to control Sclerotinia minor in four field experiments (1998–2000). In the first experiment, eight fungal isolates (Trichoderma hamatum LU595, LU593, LU592, Trichoderma virens LU555 and LU556, Coniothyrium minitans LU112, Clonostachys rosea LU115 and Trichoderma rossicum LU596) were evaluated by incorporating spore suspensions into transplant potting mix and planting lettuce seedlings into a S. minor infested field site. At harvest, Trichoderma hamatum LU595, LU593, T. virens LU555 and C. minitans LU112 reduced disease by 30–50% compared with the untreated control under very high disease pressure (100%). In further field experiments C. minitans LU112 and T. hamatum LU593, applied as maizemeal–perlite soil amendments or incorporated into the potting mix, reduced S. minor disease over a range of disease pressures (29–91%). Disease control was equivalent or greater than that achieved with the standard carbendazim fungicide treatment. Both isolates were shown to effectively colonize the lettuce rhizosphere and surrounding soil and this colonization may have protected the roots from infection by S. minor. Multiple applications of C. minitans LU112 or T. hamatum LU593 formulations gave no added disease control compared with a single application at planting. Commercial formulations of both C. minitans LU112 and T. hamatum LU593 applied as transplant treatments, solid substrate soil amendments or as a spore drench gave consistent disease control and are currently being developed further.     

Effect of herbivory by Teleonemia scrupulosa on the performance of Longitarsus bethae on their shared host, Lantana camara

Herbivory by insects may change the characteristics of nutrients and secondary plant chemicals of the foliage, thereby altering the acceptability and suitability of the plant for oviposition, feeding and development for subsequent herbivores. In the current study, the effect of herbivory by the sap-sucking lace bug, Teleonemia scrupulosa Stäl (Heteroptera: Tingidae), on the suitability of Lantana camara L. (Verbenaceae) for the root-feeding flea beetle, Longitarsus bethae Savini & Escalona (Chrysomelidae: Alticinae), was investigated under laboratory conditions. Preference of adult L. bethae was not influenced by the intensity of feeding damage caused by T. scrupulosa adults. However, high densities of T. scrupulosa nymphs and their feeding damage caused L. bethae adults to emigrate and colonize less infested or uninfested plants. Oviposition by L. bethae was significantly reduced at high densities of T. scrupulosa nymphs. While low infestation of T. scrupulosa had no effect the survival of L. bethae, moderate and high infestations caused significant reduction in percentage survival of L. bethae. The number of T. scrupulosa nymphs was negatively correlated with the percentage survival of L. bethae. Neither the duration of development nor the body size of L. bethae was influenced by the intensity of T. scrupulosa infestation. Overall, undamaged or slightly damaged plants that allowed better survival of L. bethae were often chosen as oviposition sites in preference to those that were highly infested, and on which survival was poor. Although the present study indicates the likelihood of inter-specific competition between L. bethae larvae and T. scrupulosa, this is likely to be mitigated by female flea beetles choosing to oviposit on less infested or uninfested plants in the field.     

云南兰坪云南红豆杉种群年龄结构与空间分布格局分析

利用点格局分析法对滇西北兰坪县4个云南红豆杉(Taxus yunnanensis)种群的年龄结构、不同生长阶段空间分布格局及其关联性进行分析。结果表明:(1)林窗与人为干扰影响4个云南红豆杉种群的龄级结构,小林窗的种群呈稳定型;较大林窗的种群呈进展型;群落结构完整未出现林窗和有较大人为干扰的种群年龄结构均呈衰退型,幼苗、幼树与小树个体缺乏,种群存在一定程度的更新困难,林窗的大小是种群更新的重要因素。(2)人为干扰、自然生境与本身生物学特性影响4个种群空间分布格局,种群1整体及其不同生长阶段个体均呈聚集分布;种群2和种群4在小尺度呈聚集分布,而在大尺度上呈随机分布;种群3随着空间尺度增大分布格局表现为聚集→随机→聚集趋势。(3)种群2中幼苗、小树和中树在小尺度下表现为聚集分布,其他尺度下表现为随机分布;种群3的小树阶段聚集分布和随机分布皆有出现,中树与大树在不同尺度上表现为聚集分布;种群4聚集分布的强度随生长阶段的增加在减弱。(4)4个种群各发育阶段间皆呈或接近显著正相关,种内竞争弱,有利于种群维持。     

Some ecological aspects of the copepod parasites of the common hake, merluccius hubbsi, from the argentineuruguayan coasts

A total of 2164 common hake Merluccius hubbsi captured in the Argentine-Uruguayan Common Fishing Zone was examined for parasitic copepods. The fish were infested with Chondracanlhus palpifer and Neobrachietia insidiosa f. lageniformis, the former parasitizing the buccal cavity and the latter the branchial arches. C. palpifer showed an increase in both prevalence and intensity in relation to the host size; infestation with N. insidiosa f. lageniformis decreased with increasing length of hake. Attachment site preferences and variations in the parasite distribution patterns as related to the host biology were observed. Evidence of negative association between copepod species and seasonal changes in the parasite composition was also found.     

Niche‐based relationship between sympatric bark living insect pests and tree vigor decline of Pinus yunnanensis

Forest stands of Pinus yunnanensis Franch in southwestern China are seriously damaged by several bark living insect pests. These pests commonly exist in the same host tree and exploit limited phloem resources. In this study, we hypothesized that sympatric pests would occupy different ecological niches to reduce interspecific competition, and their coordinated attack would aggravate the tree vigor decline of P. yunnanensis. To quantify the ecological niches, we used a sampling method involving three dimensional divisions of tree resource states: (a) sample plot dimension (to evaluate the extent of pest colonization at plot scale), (b) trunk height dimension, and (c) tree vigor dimension. Those attacked pine canopies and colonized trunks were analysed in the field study. The results showed that Tomicus minor and Tomicus yunnanensis both widely and uniformly distributed in lightly, moderately and heavily damaged canopies while they aggregated on particular trunks of dying and withered trees. Lower and middle trunk sections (1–4 m) were mainly occupied by Monochamus alternatus and T. minor, yet T. yunnanensis dominated the upper parts (5–6 m). There was an overlap of the pine shoot beetles in the middle sections (2–4 m), whereas all three species were ecologically segregated in other trunk sections. During the shoot feeding phase, tree vigor declined with pine shoot beetles' increasing shoot feeding density. They coexisted in the same host tree, while M. alternatus only attacked dying and withered tree trunks, causing a greater infestation. Colonization of pine shoot beetle then followed by M. alternatus could be the major causes of tree mortality. This study highlights the resource utilization pattern of sympatric bark living insect pests corresponding with tree vitality. Those findings would help to understand the mechanisms of pest outbreak in P. yunnanensis ecosystem and provide potential guidance for developing an early monitoring pest warning system.     

A newLeptographium species associated withTomicus piniperda in south-western China

Tomicus species (Coleoptera: Scolytidae) are serious pests of pines with a wide distribution in Europe, Asia and America. In Yunnan, south-western China,T. piniperda has destroyed more than 0.5 million ha ofPinus yunnanensis in the past 15 years. A blue stain fungus belonging to the genusLeptographium is associated with both the shoot-feeding and trunk-attacking stages of the beetle's life cycle. The fungus is morphologically similar to the anamorph ofOphiostoma crassivaginatum and toL. pyrinum, which are both characterised by short robust conidiophores and hyphae covered by a granular layer. Both these species have been isolated from conifers and are associated with insects. After comparing the fungus fromT. piniperda with similarLeptographium species, using light and scanning electron microscopy, we concluded that it represents a new taxon, which is described here asL. yunnanense sp. nov.     

Fruit infestation patterns by Anastrepha fraterculus and Ceratitis capitata reveal that cross‐recognition does not lead to complete avoidance of interspecific competition in nature

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庐山香果树毛竹混交林空间格局研究

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