沙棘木蠹蛾卵和幼虫空间分布的地统计学分析

沙棘木蠹蛾(H olcocerushippophaecolus Hua,Chou ,Fang et Chen)是近几年在内蒙古、辽宁、山西、宁夏和陕西等地大面积爆发的一种钻蛀性害虫,其危害发生在幼虫期,主要危害沙棘(H ippophae rhamnoidea)的根干部。为了有效地控制其危害,深入了解种群的空间结构,利用地统计学方法分析了两种受害程度不同的林分内沙棘木蠹蛾幼虫种群和重度受害林分内卵块的空间分布特性。结果表明:两种受害程度不同的林分内,沙棘木蠹蛾的危害具有显著差异,轻度受害林分内无虫样本所占的比例较大,达70 % ,而重度受害林分内不到2 0 % ;虫口密度在轻度受害林分内超过6头/株的只有6 .9% ,而重度受害林分内高达31.9%。根据全方向的变异函数曲线图分析得知:重度受害林分和轻度受害林分内幼虫种群的空间依赖范围分别为7.3m和87.4 18m,而局部空间连续性强度分别为0 .914和0 .178。重度受害林分内幼虫表现较强的空间聚集性,而轻度受害林分则表现为随机分布。在重度受害林分中,单株沙棘树上沙棘木蠹蛾卵块数量最多的为11个,最少的为1个,有卵株率达72 %。分别采用四种不同的理论模型来拟合卵块的实际变异曲线图,得知其全方向的变异函数曲线为指数型,空间依赖范围大小为3.6 m,局部空间连续性强度为0 .876 ,卵块在重度受害林分中呈现较强     

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。     

红脂大小蠹种群空间格局地统计学分析及抽样技术

红脂大小蠹是我国一重要林业外来入侵害虫,主要危害油松、白皮松和华山松,目前已扩散到山西、陕西、河北、河南、北京等地。为了研究其种群空间格局,用地统计学方法分析了受害程度不同的油松纯林和混交林林分内红脂大小蠹种群空间分布特性。结果表明:两种受害程度不同的油松纯林内红脂大小蠹的危害具有显著差异,轻度受害林分内有虫株率为4.9%,而重度受害林分则达到23.6%。全方向的变异函数曲线图分析得知:轻度受害纯林、重度受害纯林、混交林林分内红脂大小蠹种群的空间依赖范围分别为49.400、47.400\,73.820m,而局部空间连续性强度分别为0.824、0.582\,0.762。轻度受害纯林与重度受害纯林林分内红脂大小蠹种群均表现为较强的空间聚集性,而混交林受害林分内其种群则表现为随机分布。受害程度不同的纯林林分内红脂大小蠹种群空间格局具有一定的差异,而且纯林与混交林林分内其种群空间格局也有较大的差别。本文根据红脂大小蠹种群空间分布特性,对其种群空间抽样技术与传统抽样技术做了相应的比较与探讨。     

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。     

柠条绿虎天牛危害特性及其种群动态研究

柠条绿虎天牛是近年来在宁夏柠条灌丛中大面积暴发的一种钻蛀性害虫,主要以幼虫危害柠条的枝干部。论文调查研究了柠条绿虎天牛的危害特性及种群数量的动态变化。结果表明,幼虫和成虫主要分布在柠条枝干0～100cm范围内,以0～20cm处居多,其数量由基部至顶部逐渐减少。幼虫主要危害4年生以上的柠条植株,以6～8年生受害最重。随着柠条地径的增加,天牛成虫数量逐渐增加,而幼虫数量则呈现先增加再减少的变化趋势。不同时期幼虫数量在枝干上的分布变化较大,幼虫具有转移危害习性,先由基部和顶部向中部转移,随着气温的不断降低,则由顶部不断向基部转移,以0～20cm处的数量最多,可能柠条枝干基部的环境更有利于幼虫的越冬。     

杨树上云斑天牛种群的空间格局及抽样技术

云斑天牛Batocera horsfieldi是我国南方杨树的重要蛀干害虫, 研究云斑天牛种群的空间格局和抽样技术, 可为该虫的危害调查与防治提供理论依据。应用Taylor的幂法则、Iwao m*-m回归分析法及6个聚集指标, 对云斑天牛种群的卵、幼虫、蛹或成虫的空间分布型和抽样技术进行了研究, 并做了影响因素分析。结果表明: 云斑天牛的卵、幼虫、蛹或成虫在杨树上均呈聚集分布, 分布的基本成分是个体群, 其聚集性随密度的增加而增大。运用Iwao m*-m回归中的两个参数α和β值, 计算出了在不同精度下以刻槽、排粪孔和羽化孔为防治指标时的理论抽样数据表及序贯抽样数据表,生产中可查阅使用。     

不同寄主来源种群花绒寄甲成虫对桃红颈天牛幼虫虫粪的行为趋性和种群控制效果

【目的】桃红颈天牛Aromia bungii是危害桃、杏、李、樱桃的主要蛀干害虫,花绒寄甲Dastarcus helophoroides是一种能有效防治多种天牛类林木钻蛀害虫的重要天敌昆虫。本研究通过比较不同寄主来源种群花绒寄甲对桃红颈天牛幼虫虫粪的行为反应和对幼虫控制能力的差异,旨在筛选能够有效防治桃红颈天牛的花绒寄甲种群。【方法】采用Y型嗅觉仪测定了6个不同寄主来源种群花绒寄甲成虫对桃红颈天牛幼虫虫粪的行为趋性;采用纱网罩受害原木模拟自然条件,释放不同种群花绒寄甲成虫测定了其对桃红颈天牛的致死效果。【结果】行为趋性结果表明,源自松褐天牛和云斑天牛的花绒寄甲种群对桃红颈天牛幼虫虫粪表现出明显的正趋向反应,而源自光肩星天牛、星天牛、锈色粒肩天牛和栗山天牛这4个种群的花绒寄甲对桃红颈天牛幼虫虫粪均未表现出明显的趋向反应。持续2年的寄生控制实验表明,源自光肩星天牛的花绒寄甲种群致死效果较好,天牛死亡率为52.86%±5.97%,源自松褐天牛、云斑天牛、栗山天牛和锈色粒肩天牛的花绒寄甲种群控制效果依次降低,天牛死亡率分别为35.14%±5.55%,32.88%±5.50%,26.09%±5.29%和10.94%±3.90%,源自星天牛的花绒寄甲种群未显示出对桃红颈天牛的控制作用。【结论】利用花绒寄甲防治桃红颈天牛时,应选择源自松褐天牛、云斑天牛或光肩星天牛的花绒寄甲种群。     

云南松三种同域共存切梢小蠹梢转干期的空间分布格局

分布在我国西南地区的横坑切梢小蠹,云南切梢小蠹和短毛切梢小蠹同域危害寄主云南松,给林业生产带来巨大损失。为探讨同域切梢小蠹种群在共存下对其空间分布格局的影响,采用传统聚集指标法和地统计学方法研究了三者在梢转干期不同受害云南松纯林树冠中的空间分布型。结果表明重度受害样地中云南切梢小蠹种群密度显著高于横坑切梢小蠹,在轻度受害样地则相反;传统聚集指标法结果显示同域共存的3种切梢小蠹种群在不同受害程度云南松中均为聚集分布,横坑切梢小蠹和云南切梢小蠹聚集是由环境因素和昆虫本身的聚集习性引起;地统计学结果表明除重度受害样地中短毛切梢小蠹呈随机分布外,其余切梢小蠹在不同种群密度下均呈聚集分布;除重度受害样地横坑切梢小蠹外,其他小蠹的空间依赖范围为4.01—7.45 m。横坑切梢小蠹和云南切梢小蠹在不同受害林分中拟合的半变异函数模型在球形模型和高斯模型之间转换。同域共存关系不影响不同种群密度下的切梢小蠹种群空间分布类型,但影响其半变异函数模型和理论参数。     

林间花斑花绒寄甲幼虫种群动态及空间分布格局

花绒寄甲Dastarcus helophoroides Fairmaire以幼虫寄生松褐天牛Monochamus alternatus等天牛类害虫,掌握其幼虫时空动态和空间分布格局,有助于制定花绒寄甲的生物防治利用策略。通过对江西马尾松林花绒寄甲幼虫种群数量的调查,应用聚集度指标和回归分析等,对林间花绒寄甲幼虫种群动态、水平分布和垂直分布进行了研究。结果表明,林间花绒寄甲幼虫种群动态呈现极明显的波动性,全年数量动态有2个高峰期,其中主高峰期是4月份,占全年幼虫总数量的30%左右,是幼虫的主要寄生期,次高峰期是8月份。花绒寄甲幼虫水平空间分布为聚集分布,分布的基本成分是个体群,聚集的原因可能是花绒寄甲自身习性或与寄主天牛、环境因素共同作用所致。不同时间段,花绒寄甲幼虫的垂直分布情况不同,3-7月,花绒寄甲幼虫主要分布在枯死木的中上部,其中上段幼虫数占总数的50%以上,而在8-12月,花绒寄甲幼虫主要分布在枯死木的中段,占总数的50%左右。另外,调查显示,花绒寄甲幼虫寄生数量在释放过该天敌的松林要远高于未释放过的松林,特别是在马尾松纯林,其幼虫种群数量更高,这说明通过人工释放（江西在3月释放成虫）,能增加林间天敌花绒寄甲种群数量、降低松褐天牛种群数量,有助于松材线虫病的控制。花绒寄甲幼虫种群时空、水平、垂直三维空间分布结果可为该天敌的保护、人工释放和有效利用提供科学依据。     

松树蜂形态及危害特点的研究

在发生松树蜂的林场利用"五点取样法"进行调查,调查样方内树木种类、胸径大小、生长情况、蛀干害虫种类和在树干上的分布情况;同时,选取虫害木,解剖并统计不同蛀干害虫的羽化孔数量和特点,幼虫钻蛀特征和危害特点;研究松树蜂自然种群的寄主选择规律和垂直分布特点。结果表明,松树蜂在我国仅危害衰弱的樟子松,30-40年生的中龄林受害最严重,平均有虫株率为10.94%±8.67%。松树蜂产卵后的树皮表面有流树脂现象,呈点状或流泪状。同松幽天牛和吉丁危害状不同,松树蜂羽化孔呈正圆形,直径大小约为7 mm,分布在树干0-4.20 m的高度,其中90%的集中分布在0-3 m范围内。松树蜂幼虫坑道横截面为正圆形,无排粪孔,虫粪和蛀屑都呈粉末状,紧实堆满蛀道,颜色和蛀道周围颜色无明显差异。     

Effect of the nematicide oxamyl on the multiplication of Globodera rostochiensis and G. pallida and on the haulm growth and yield of six potato cultivars with different levels of resistance and tolerance

The effect of a pre-planting application of oxamyl on the yields of six potato cultivars was studied in co-operative field trials in 1981. Two sites were ‘uninfested’ with potato cyst nematodes (PCN), two were lightly infested (<25 eggs/g soil) and six were moderately to heavily infested (three with Globodera rostochiensis and three with G. pallida). At the uninfested and lightly infested sites oxamyl had little effect on mid-season haulm weights or on final tuber yields. At sites moderately to heavily infested with G. rostochiensis the haulm growth of all cultivars tended to be increased by a similar amount on plots treated with oxamyl, Pentland Dell being least responsive. Yield was increased by different amounts, the increases being least for cvs Cara and Maris Piper and most for Corsair and Pentland Dell. At the sites moderately to heavily infested with G. pallida Cara was again tolerant, its yield being increased little by oxamyl compared with the other cultivars. Maris Piper gave the largest yield increase. Final populations of PCN on non-resistant cultivars were reduced by oxamyl at some sites but not at others. Resistant cultivars also decreased the final numbers of PCN at most sites. Two cultivars derived from Solanum vernei with different degrees of resistance, appeared to be almost equally effective in controlling G. rostochiensis and G. pallida.     

Variation in rates of leaf abscission between plants may affect the distribution patterns of sessile insects

Summary At Sand Lake, Leon County, Florida, mines of Stilbosis quadricustatella, a leaf-mining moth, occur on sand live oak trees (Quercus geminata) over a broad range of densities. Some trees have fewer than 2% of their leaves mined (lightly infested), others up to 70% (heavily infested). Similar levels of infestation are maintained on the same trees year after year. There are no significant negative correlations of miner density per tree with any mortality factor that might explain miner preferences for certain trees. Nor is there a positive correlation with host leaf quality as measured by foliar nitrogen or by total or individual amino acid concentrations of host leaves. Egg-transfer experiments showed that larvae from eggs transferred to lightly infested trees were more likely to be killed by leaf abscission than were those that were transferred to and developed on heavily infested trees. This is the first demonstration that variation in rates of leaf abscission could be an important cause of the observed distribution pattern of sessile insects between conspecific host plants.     

Induced Response of Tomato Plants to Injury by Green and Red Strains of Tetranychus Urticae

We studied the induced response of tomato plants to the green strain and the red strain of the spider mite Tetranychus urticae. We focused on the olfactory response of the predatory mite Phytoseiulus persimilis to volatiles from T. urticae-infested tomato leaves in a Y-tube olfactometer. Tomato leaves attracted the predatory mites when slightly infested with the red strain, or moderately or heavily infested with the green strain. In contrast, neither leaves that were slightly infested with green-strain mites, nor leaves that were moderately or heavily infested with the red strain attracted the predators. We discuss the specific defensive responses of tomato plants to each of the two strains.     

New method for rapidly estimating population densities of the concealed wood‐borer Monochamus alternatus (Coleoptera: Cerambycidae) in the field

To rapidly estimate pine sawyer, Monochamus alternatus Hope, population densities in forests, the vertical distributions of M. alternatus oviposition sites and larvae on infested Masson pines (Pinus massoniana Lamb.) were studied. Results showed that the number of oviposition sites on sections of trunks between 0 and 2 m above ground was significantly greater than on sections of trunk above 2 m, and the vertical distribution had a significant logarithmic relationship with trunk height. The larval number of M. alternatus on dead infested trees had a significant difference among heights of trunks. Sections on trunks at 2–4 m usually contained the largest number of M. alternatus larvae, while the number of larvae on trunks above 10 m declined significantly, as well as in the 1 m section of trunk at the base. The vertical distribution of M. alternatus larvae on dead infested pines showed a distinct parabolic relationship with trunk height. The number of oviposition sites of M. alternatus on infested Masson pine trunks revealed a significant exponential relationship with the diameter at breast height (DBH) of trees. A significant positive linear relationship also was observed between M. alternatus larval number and DBH on the host pine trees, as well as between the numbers of larvae and oviposition sites on an individual tree. The total number of larvae in an infested tree could be calculated easily using an established equation, through counting the number of oviposition sites at 3–4 m of trunk aboveground. This study developed a practical method for rapid estimation of M. alternatus populations.     

Spatial distribution of Holcocerus hippophaecolus (Lepidoptera: Cossidae) pupae in a seabuckthorn (Hippophae rhamnoides) stand

The seabuckthorn carpenter moth, Holcocerus hippophaecolus, which has a generation time of four years, is recently becoming one of the major pests of the seabuckthorn (Hippophae rhamnoides) in Inner Mongolia, Liaoning, Shanxi, Ningxia and Shaanxi of China (Hua et al., 1990). The larvae of the H. hippophaecolus mainly damage the stems and roots of the seabuckthorn, and the mature larvae pupate in the soil. The spatial distribution of the pupae was analyzed by using biostatistics and geostatistics in order to effectively control the insect and further study the spatial distribution of the population. Results show that most of the pupae (90%) had an eclosion time span from early June to the end of July. The sex ratio of the pupae was nearly 1:1 in the woodland samples. In addition, 24.3% of the 971 trees investigated had pupae and it ranged from 0 to 4 per tree within a distance of 1.3 m from the base of the stem. 90% of the pupae were aggregated within a distance of 1 m from the base of the stem. The pupae show intense spatial aggregation in the sampled woodland which had an 11.1 m spatial dependence and a 90.7% intensity in the local spatial continuity. Moreover, the population presented an intensive spotted distribution and many aggregated spots were found in the woodlands. As for the relationship between grid size and variogram of the pupae, the variations in the range, the intensity of local spatial continuity and the sill were all very low or non-existent when the grid size was 5 m, 6 m or 7 m. Whereas, the value of the decisive coefficient was the biggest when the grid size was 5 m making it the ideal grid size. __________ Translated from Acta Ecologica Sinica, 2006, 26(10): 3232–3237 [译自: 生态学报]     

A comparative study of predation of three aquatic heteropteran bugs on Culex quinquefasciatus larvae

The aquatic bugs Anisops bouvieri Kirkaldy 1704 (Heteroptera: Notonectidae), Diplonychus (=Sphaerodema) rusticus Fabricius 1781, and Diplonychus annulatus Fabricius 1781 (Heteroptera: Belostomatidae) are common members of the freshwater insect communities of the East Calcutta Wetlands along the eastern fringe of Kolkata, India. These insects are established predators of dipteran larvae and other organisms. A comparative account of their predatory efficiency was made using larvae of Culex quinquefasciatus Say 1823 in the laboratory. It was revealed that a single adult of A. bouvieri could consume 28–34 fourth-instar mosquito larvae per day, D. rusticus 11–87 fourth-instar mosquito larvae per day, and D. annulatus 33–122 fourth-instar mosquito larvae per day, depending upon the prey and predator densities. The mean predation rate of A. bouvieri and D. annulatus remained stable over a 6-day feeding period but varied for D. rusticus. The predatory impact (PI) values were 14.77–17.31, 46.9–55.73, and 61.74–72.72 larvae/day for A. bouvieri, D. rusticus, and D. annulatus, respectively. Compared to these, the clearance rate (CR) value range was 9.06–13.25 for A. bouvieri, 13.64–15.99 for D. rusticus, and 13.50–16.52 larvae l/day/predator for D. annulatus. The values of mutual interference, “m,” remained 0.06–0.78 for A. bouvieri, 0.003–0.25 for D. rusticus, and 0.09–0.27 for D. annulatus, and did not vary between the days. The difference in predatory efficiency, CR, and PI values varied significantly among the three predators, indicating the possible difference in the function as predators occupying the same guild. It can be assumed that these predators play an important role in larval population regulation of mosquitoes and thereby impart an effect on species composition and interactions in the aquatic insect communities of the wetlands and other similar habitats where they occur.