衡阳市区主要园林树木害虫的种类与危害研究

在调查、采集和饲养的基础上,共鉴定出衡阳市主要园林树木害虫84种.并分析了衡阳市区主要园林树木害虫的发生危害特点,提出了相应的防治策略.     

马尾松不同林型对土壤理化性质的影响

以安徽省枞阳县大山村3种马尾松不同林型（马尾松纯林、马尾松-麻栎混交林、马尾松-枫香混交林）0~60 cm土层为研究对象,探讨3种马尾松林型的土壤理化性质变化规律,旨在为该区马尾松人工林的可持续发展和生产提供科学依据。结果表明：（1）0~60 cm土层,3种马尾松林型土壤容重随深度的增加而逐渐增加,混交林土壤容重显著低于纯林;土壤含水量随土层的加深而逐渐减小,其大小为：马尾松-枫香混交林>马尾松-麻栎混交林>马尾松纯林,马尾松-枫香混交林在土壤容重降低,土壤孔隙度增加及土壤含水量方面优于马尾松-麻栎混交林;（2）土壤pH值介于4.5~5.0之间,3种林型pH值随土层深度的增加而增大,但差异均不显著,其中马尾松-枫香混交林土壤pH值较高;（3）3种林型土壤有机质、全N、有效P和速效K均随土层深度的增加而减少,呈现明显的“表聚”现象,其质量分数表现为：马尾松-枫香混交林>马尾松-麻栎混交林>马尾松纯林;（4）土壤容重与土壤水分质量分数、有机质、全N、有效P和速效K等养分质量分数均呈负相关,土壤有机质与全N、有效P和速效K呈极显著的正相关,这说明土壤有机质在改善土壤理化性质和促进养分循环方面起着非常重要的作用。     

浙江省萧山市山一村农村生态良性循环与系统管理研究 Ⅴ.农田病虫害综合防治试验与实施

本项调控工程分两步:1984—1986年在山一村106ha农田开展病虫害综合防治试验示范;1987—1989年将试验成果应用于生产。试验研究取得了明显的经济效益、生态效益和社会效益:农药用量比1983年前减少80.6％,稻谷中农药残留不超标(原有机氯农药666残留超标率31.6％);害虫天敌稻田蜘蛛增加83.3—180.0％,稻虱多索线虫增加2倍;防治农药成本减少53.7％。并制定了《山一村农田农药污染防治技术规程》,其主要内容有:开展病虫害“二查二定”,达到防治指标时用药;制定病虫害防治策略,在防治适期内用药;推广高效低残留农药,遵守农药安全间隔期;推广抗性良种,适施N肥,增施P、K肥;保护利用天敌,发挥天敌自然抑制作用。     

湘南地区天草主要病虫害发生特点及综合防治

天草主要病害有炭疽病、煤烟病、日灼病和缺素症,主要害螨害虫有红蜘蛛、锈壁虱、蚜虫、潜叶蛾、柑桔象虫类、柑桔凤蝶和介壳虫类.文章总结了这些主要病虫害在天草上发生特点、时期及防治方法.     

汉寿县林业害虫调查分析与建议

林业害虫调查是开展林业害虫预测预报、防治检疫的基础.调查旨在查清汉寿县各林分类型的害虫种类、数量、分布区域和发生情况等,并针对危害严重的黄翅大白蚁(Macrotermes barneyi)进行了重点分析,为汉寿县林业害虫的预测预报和防治设计提供可靠的科学依据.     

害虫生物防治的景观调节途径:原理与方法

应用景观管理促进天敌生物的多样性进而将害虫群落控制在较低水平,成为近些年害虫防治的新途径。在回顾国内外研究的基础上,重点介绍景观管理调节农业景观生物多样性和害虫生物防治的原理,系统总结目前国内外现有农业景观害虫生物防治的景观管理途径和方法。最后,就国内农业政策下推行景观管理、促进害虫防治面临的问题和发展方向进行探讨。     

南京南郊马尾松种群动态及种内竞争模型的应用

通过对南京南郊马尾松(Pinus massoniana)种群年龄结构的统计,绘制该种群的静态生命表。结果表明,该马尾松种群年龄结构属衰退型;存活曲线为凸形曲线,属Deevey-A型;死亡率和消失率变化规律一致,均在第11龄级(47~49 a)时取得极大值,分别达0.625和0.981。对群落Hegyi竞争指数的计算表明,种内竞争是马尾松种群衰退的主要原因:种内竞争指数占总竞争指数的85.8%,种内平均单木竞争指数为1.71,而种间竞争指数仅占总竞争指数的14.2%。非线性回归结果表明,用林振山种内竞争模型拟合南京南郊马尾松种群数量的衰退规律可以达到较高优度,判定系数为0.759,此地马尾松种群固有出生率为0.105,环境对马尾松的最大容量为31株·(400 m2)-1。模型稳定性分析表明,马尾松种群虽然处于衰退阶段,但种群不会退出该地区,并将在未来很长时间保持群落优势种的地位,种群密度最终将衰退至9.396株·(400 m2)-1的稳定状态。     

触破式微胶囊剂防治城市害虫展望

论述了触破式微胶囊农药在园林害虫防治中的优点和发展过程，对触破式微胶囊剂在城市害虫防治中的发展前景进行了展望，这有助于人们在城市园林害虫防治中采用正确的方法，减少对城市环境的污染，营造一个有利于身心健康的城市居住空间。     

不同基质对马尾松容器苗及其菌根的影响

以10种培养基质，对马尾松进行容器育苗研究．结果表明：以竹叶为基本材料配制基质，比纯黄心主基质培育的马尾松百日苗，干物质重增加对2％；与蛭石基质相比，增加43.9％；与松树皮基质相比，增加25.0％以松针为基本材料配制的基质效果近似于竹叶．两者对苗木生长的影响，与各处理相比较，均达到了极显著水平．培养基质理化性质与苗木生物量相关的矩阵分析表明，容器基质的客重和孔隙度对苗木生长影响最大;基质内有效养分含量，特别是磷含量的多少很重要．竹叶和松针作为基质，表现了良好的理化性质，促进了马尾松苗木早期菌极化，百日苗面根感染率分别比黄心土基质的百日苗提高12.9％和17.0％同时加快了苗木生长．     

南方红壤区西南桦和马尾松人工林土壤微生物活性及细菌多样性比较

目前,西南桦(Betula alnoides)和马尾松(Pinus massoniana)均是广西红壤区大规模种植的人工林树种。为了分析和评价这两个树种对土壤肥力和生态质量的影响,本文采用了稀释平板法和氯仿熏蒸提取法等传统方法分析了两种人工林土壤可培养微生物数量、微生物量碳、微生物量氮、涉及土壤碳、氮、磷循环相关酶活性等表征微生物活性的指标。同时,采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)技术分析了两种人工林土壤细菌多样性。结果表明,西南桦人工林土壤中可培养真菌数量与马尾松人工林虽无明显差异,但可培养细菌和放线菌数量均明显高于相应的马尾松人工林。土壤中β-葡萄糖苷酶、磷酸酶和蛋白酶活性在两种人工林之间虽无明显差异,但西南桦人工林各土层土壤的微生物生物量碳、氮指标均优于对应的马尾松林,表现出比马尾松更优的生态效果。此外,西南桦人工林土壤中各土层细菌多样性指数(Shannon-Wiener index)均高于相应的马尾松人工林土层。综上,比马尾松相比,西南桦是更有利于提高红壤区土壤肥力和维持林地土壤生态质量的造林树种。     

On the relative contributions of wind vs. animals to seed dispersal of four Sierra Nevada pines

Selective pressures that influence the form of seed dispersal syndromes are poorly understood. Morphology of plant propagules is often used to infer the means of dispersal, but morphology can be misleading. Several species of pines, for example, have winged seeds adapted for wind dispersal but owe much of their establishment to scatter-hoarding animals. Here the relative importance of wind vs. animal dispersal is assessed for four species of pines of the eastern Sierra Nevada that have winged seeds but differed in seed size: lodgepole pine (Pinus contorta murrayana, 8 mg); ponderosa pine (Pinus ponderosa ponderosa, 56 mg); Jeffrey pine (Pinus jeffreyi, 160 mg); and sugar pine (Pinus lambertiana, 231 mg). Pre-dispersal seed mortality eliminated much of the ponderosa pine seed crop (66%), but had much less effect on Jeffrey pine (32% of seeds destroyed), lodgepole pine (29%), and sugar pine (7%). When cones opened most filled seeds were dispersed by wind. Animals removed > 99% of wind-dispersed Jeffrey and sugar pine seeds from the ground within 60 days, but animals gathered only 93% of lodgepole pine seeds and 38% of ponderosa pine seeds during the same period. Animals gathered and scatter hoarded radioactively labeled ponderosa, Jeffrey, and sugar pine seeds, making a total of 2103 caches over three years of study. Only three lodgepole pine caches were found. Caches typically contained 1-4 seeds buried 5-20 mm deep, depths suitable for seedling emergence. Although Jeffrey and sugar pine seeds are initially wind dispersed, nearly all seedlings arise from animal caches. Lodgepole pine is almost exclusively wind dispersed, with animals acting as seed predators. Animals treated ponderosa pine in an intermediate fashion. Two-phased dispersal of large, winged pine seeds appears adaptive; initial wind dispersal helps to minimize pre-dispersal seed mortality whereas scatter hoarding by animals places seeds in sites with a higher probability of seedling establishment.     

Application of Agriculture‐Developed Demographic Analysis for the Conservation of the Hawaiian Alpine Wekiu Bug

Insects that should be considered for conservation attention are often overlooked because of a lack of data. The detailed information necessary to assess population growth, decline, and maximum range is particularly difficult to acquire for rare and cryptic species. Many of these difficulties can be overcome with the use of life table analyses and heat energy accumulation models common in agriculture. The wekiu bug (Nysius wekiuicola), endemic to the summit of one volcanic mountain in Hawaii, is a rare insect living in an environmentally sensitive alpine stone desert, where field‐based population assessments would be inefficient or potentially detrimental to natural and cultural resources. We conducted laboratory experiments with the insects by manipulating rearing temperatures of laboratory colonies and made detailed observations of habitat conditions to develop life tables representing population growth parameters and environmental models for wekiu bug phenology and demographic change. Wekiu bugs developed at temperatures only found in its environment on sunny days and required the thermal buffer found on cinder cones for growth and population increase. Wekiu bugs required approximately 3.5 months to complete one generation. The bug developed optimally from 26 to 30 °C, temperatures that are much higher than the air temperature attains in its elevational range. The developmental temperature range of the species confirmed a physiological reason why the wekiu bug is only found on cinder cones. This physiology information can help guide population monitoring and inform habitat restoration and conservation. The wekiu bug was a candidate for listing under the U.S. Endangered Species Act, and the developmental parameters we quantified were used to determine the species would not be listed as endangered or threatened. The use of developmental threshold experiments, life table analyses, and degree day modeling can directly inform otherwise unobservable habitat needs and demographic characteristics of extremely rare insects. Aplicación de Análisis Demográfico de Desarrollo Agrícola para la Conservación del Insecto Weiku Alpino Hawaiano     

Protection from Natural Enemies in Managing Rare Plant Species

Abstract: Natural enemies such as pathogens, herbivores, and seed predators can substantially limit the abundance of plants, including rare species. Vulnerability to particular enemies is likely to differ between life-history stages. We hypothesized that short-term protection of juvenile plants from herbivores can be used to increase population growth of rare species and thus improve the probability of long-term persistence. Using the federally listed (threatened) Pitcher's thistle ( Cirsium pitcheri ) as a model, we experimentally excluded insect herbivores from juvenile rosettes to evaluate the potential benefits of deliberate insect control as a tool for management of rare species. Herbivore effects varied spatially across the local environment. Excluding insects in portions of the habitat where herbivory was high had direct benefits, including a 53% decrease in juvenile plant mortality (60% to 7%) and a 10-fold increase in seed production of juveniles that matured and flowered. In other areas, where herbivore-induced juvenile mortality was relatively low, excluding insects either increased seed production of plants that flowered or had no major effect. Our data also suggest indirect benefits to the metapopulation via potential improvement in dispersal among patches. Temporal variation in growing conditions occurred between years, suggesting that multiple-year exclusions would be most effective. Our study suggests that small–scale manipulation of often inconspicuous interactions between rare plants and their natural enemies can be an effective, relatively low-cost tool for the management and restoration of rare plant species.     

The functional response of a hoarding seed predator to mast seeding

Mast seeding involves the episodic and synchronous production of large seed crops by perennial plants. The predator satiation hypothesis proposes that mast seeding maximizes seed escape because seed predators consume a decreasing proportion of available seeds with increasing seed production. However, the seed escape benefits of masting depend not only on whether predators are satiated at high levels of seed production, but also on the shape of their functional response (type II vs. type III), and the actual proportion of available seeds that they consume at different levels of seed production. North American red squirrels (Tamiasciurus hudsonicus) are the primary vertebrate predator of white spruce (Picea glauca) mast seed crops in many boreal regions because they hoard unopened cones in underground locations, preempting the normal sequence of cone opening, seed dispersal, and seed germination. We document the functional response of cone-hoarding by red squirrels across three non-mast years and one mast year by estimating the number of cones present in the territories of individual red squirrels and the proportion of these cones that they hoarded each autumn. Even though red squirrels are not constrained by the ingestive and on-body (fat reserves) energy reserve limitations experienced by animals that consume seeds directly, most squirrels hoarded < 10% of the cones present on their territories under mast conditions. Cone availability during non-mast years also reached levels that satiated the hoarding activity of red squirrels; however, this occurred only on the highest-quality territories. Squirrels switched to mushroom-hoarding when cone production was low and mushrooms were abundant. This resulted in type III functional response whereby the proportional harvest of cones was highest at levels of cone availability that were intermediate within non-mast years. Overall, more cones escaped squirrel cone-hoarding during a mast event than when cone production was low in non-mast years, which supports the predator satiation hypothesis. However, the highly variable seed escape in non-mast years may help to explain why all spruce cone production is not concentrated into fewer, larger, mast years.     

Disease prevention and resistance in social insects: modeling the survival consequences of immunity,hygienic behavior,and colony organization

Understanding the origin of disease resistance in social insects is difficult due to the lack of well-established phylogenies of presocial and eusocial species and the absence of extant basal and intermediate forms. Moreover, comprehensive accounts of infection-control traits in social insect lineages are not available. Therefore, to explore the evolution of pathogen control in social insects we used cellular automata models to analyze the efficacy of immunity and nest hygiene, which we assumed were basal traits, and allogrooming, which likely followed the transition to eusociality, and their interactions with colony demography and patterns of worker spatial distribution. Models showed that nest hygiene provided an immediate survival benefit and that immunity lowered overall disease susceptibility under both constant and periodic exposure scenarios. Allogrooming increased survivorship in chronically challenged colonies but also increased pathogen transmission rates under conditions of periodic exposure. Colonies having demographies biased towards young or old individuals had slightly higher mortality than those with heterogeneous demographies. The distribution of older individuals relative to the nest center had no significant effect on susceptibility and provided only a minor survival advantage. Models indicated that nest hygiene and immunity function on different temporal scales and can interact with demography to lower disease risks. Our results suggest how infection control systems in social insects could have been built upon the inducible immune defenses and nest hygienic behaviors of solitary and presocial ancestors and served as important preadaptations to manage disease exposure and transmission in colonies of eusocial species.     

Insecticidal and antifungal chemicals produced by plants: a review

Leaf-cutting ants of the Attini tribe are a major pest of agricultural and forestry productions in the New World. Economic losses caused by these ants were estimated at several million dollars per year. These ants need to live in symbiosis with a basidiomycete fungus. Due to their mutualistic interaction with the symbiotic fungus, management of Attini ants can be done with insecticides or fungicides or both. So far, synthetic pesticides were the main control means, albeit with negative effects on the environment. Very few studies describe alternative methods for the control of leaf-cutting ants such as the use of insecticidal and fungicidal plant extracts. There is therefore a need of knowledge on phytochemicals and plants that could be used as insecticides and fungicides. Here, we review chemicals of plant origin and species with insecticidal and fungicidal activities. We establish a list of plants and phytochemicals that could manage leaf-cutting ants and also other insects, notably insects that use fungus-based agriculture. An exhaustive literature search of 1965 references from 1923 to 2010 was conducted using scientific databases, chemical databases, botanical databases, and books to identify published papers related to insecticidal and fungicidal chemical compounds stemmed from plant species. The major points are the following: (1) 119 and 284 chemicals have been cited in the literature for their insecticidal and fungicidal activities, respectively; (2) 656 and 1,064 plant species have significant insecticidal and fungicidal activities, respectively; (3) 3 main chemical classes were most cited for these activities: alkaloids, phenolics, and terpenoids; (4) 20 interesting chemicals with the both insecticidal and fungicidal activities were found; and (5) 305 plant species containing these chemicals were cited. To conclude, 20 chemicals: caryophyllene oxide, cinnamaldehyde, eugenol, helenalin, linalool, menthone, myristicin, pulegone, thymol, anethole, anisaldehyde, elemicin, isopimpinellin, plumbagin, podophyllotoxin, psoralen, xanthotoxin, anonaine, solamargine, and tomatine; two main plant families, Lamiaceae and Apiaceae; and 17 species of these families were particularly interesting for the management of leaf-cutting ants.     

Seed predation and selection exerted by a seed predator influence subalpine tree densities

Strongly interacting species often have pronounced direct and indirect effects on other species. Here we focus of the effects of pine squirrels (Tamiasciurus spp.), which are a dominant pre-dispersal seed predator of many conifers including limber pines (Pinus flexilis) and whitebark pines (P. albicaulis). Pine squirrels depress seed abundance by harvesting most limber and whitebark pine cones on their territories. Pine squirrels further reduce seed availability for Clark's Nutcrackers (Nucifraga columbiana), the primary seed disperser of these pines, because selection exerted by pine squirrels has reduced the number of seeds per cone and causes seeds to be less accessible. We predicted that, if fewer seeds were available for dispersal by nutcrackers, pine recruitment should be suppressed in areas with pine squirrels. In support of this prediction, stand densities were about two times greater in areas where pine squirrels are absent than in areas where they are present. Alternative explanations that we considered do not account for these differences; however, precipitation may limit stand densities in the absence of seed limitation by pine squirrels. In sum, pine squirrels apparently depress limber and whitebark pine stand densities, with the potential for ecosystem impacts because these pines are foundation species within Western subalpine ecosystems.     

Costs and benefits of capsaicin-mediated control of gut retention in dispersers of wild chilies

A fundamental way in which animal-dispersed plants can influence the viability and distribution of dispersed seeds is through control of retention time in the guts of dispersers. Using two species of wild chilies and their dispersers, we examined how chemical and physical properties of fruits and seeds mediate this interaction. Capsicum chacoense is polymorphic for pungency, occurs in Bolivia, and is dispersed mostly by elaenias. Capsicum annuum is not polymorphic, occurs in Arizona (USA), and is dispersed mostly by thrashers. We first tested whether capsaicin, the substance responsible for the pungency of chilies, affects gut retention time of seeds in primary dispersers. Capsaicin slowed gut passage of seeds but did so in a manner that differed greatly between bird species because the constipative effects of capsaicin occurred only after an 80-minute time lag. Elaenias in Bolivia held only 6% of C. chacoense seeds for > 80 minutes, whereas thrashers in Arizona held 78% of C. annuum seeds for > 80 minutes. Next we examined the effects of retention time on seed viability and germination. Increased retention resulted in a greater proportion of seeds germinating in C. annuum, had no effects on non-pungent C. chacoense, and had negative effects on pungent C. chacoense. These divergent effects are explained by differences in seed coat morphology: seed coats of pungent C. chacoense are 10-12% thinner than those of the other two types of seeds. Thus, longer retention times damaged seeds with the thinnest seed coats. In C. annuum, seed viability remained high regardless of retention time, but germination increased with retention, suggesting a role for scarification. Thus, in C. annuum, fruit chemistry appears well matched with seed morphology and disperser physiology: capsaicin extends gut retention for most seeds, resulting in greater seed scarification and higher germination rates. Increased retention of pungent C. chacoense seeds is detrimental, but because the primary consumers have short retention times, capsaicin slows only a small proportion of seeds, minimizing negative effects. These results illustrate the importance of context in studies of fruit secondary metabolites. The same chemical can have different impacts on plant fitness depending on its morphological, physiological, and ecological context.     

Mast seeding under increasing drought: results from a long-term data set and from a rainfall exclusion experiment

Mast seeding, the synchronous, highly variable seed production among years, is very common in tree species, but there is no consensus about its main causes and the main environmental factors affecting it. In this study, we first analyze a long-term data set on reproductive and vegetative growth of Quercus ilex in a mediterranean woodland in order to identify the main environmental drivers of interannual variation in flower and seed production and contrast the impact of climate vs. adaptive factors as main causes of masting. Second, we conducted an experiment of rainfall exclusion to evaluate the effects of an increasing drought (simulating predictions of global change models) on both reproductive processes. The annual seed crop was always affected by environmental factors related to the precipitation pattern, these abiotic factors disrupting the fruiting process at different periods of time. Seed production was strongly dependent upon water availability for the plant at initial (spring) and advanced (summer) stages of the acorn maturation cycle, whereas the final step of seed development was negatively affected by the frequency of torrential-rain events. We also found clear evidence that seed masting in the study species is not only regulated by selective endogenous rhythms, but is mainly a physiological response to the variable environment. Our results from the rainfall exclusion experiment corroborated the conclusions obtained from the 26-year fruiting record and demonstrated that the high interannual variation in seed crop was mainly determined by the success in seed development rather than by the flowering effort. Under a global change scenario, it could be expected that the drier conditions predicted by climate models reinforce the negative effects of summer drought on seed production, leading to negative consequences for tree recruitment and forest dynamics.     

Bumblebees as model organisms to study male sexual selection in social insects

Social-insect males are often regarded as being merely short-lived "flying sperm containers", which ignores their potential influence on females and paternity patterns as found in other animals. Consequently, social-insect males have received only marginal attention and sexual selection has almost never been studied in these species. Here I present a review of the mating biology of bumblebees (Bombus spp.), which are the best-studied social insects to date. I follow a male's pathway from his birth until he successfully contributes to the next generation, and show that males have evolved adaptations and behaviors to influence paternity patterns at various stages of their life, which are similar to those exhibited by males of non-social insects. By comparing the available bumblebee data with more sparse studies of male reproductive behavior in other social Hymenoptera, I argue that such male adaptations may indeed be widespread in social insects. I suggest that current paradigms on sexual selection should be challenged by using social insects as model systems, because they offer unique features, and a solid theoretical background in which clear predictions can be made and appropriate experimental tests of them can be designed.Communicated by A. Cockburn