昆虫种群发育数量动态的模拟模型及其应用

在评述国内外近十几年来昆虫种群发育模拟模型研究的基础上,充分考虑了不同昆虫的种群发育特点,建立了以种群发育温度为驱动变量,以昆虫种群生命表资料为基础数据的具有发育阶段和年龄结构的通用发育模型。模型可用于模拟具有不同虫态数及各虫态没年龄烽的种群发育进程。在与天气耦联的情况下,可用于昆虫种群发生动态的预测和不同防治策略的风险分析,对玉变螟生命表资料的模拟结果表明,模型具有良好的模拟性能。     

Population Dynamics of the Field Vole (Microtus agrestis [L]): a Model1

The basic hypothesis underlying a population dynamics model for the field vole (Microtus agrestis [L.]) in central Scandinavia is described and discussed. The hypothesis is that most aspects of population dynamics of the field vole may be understood by analyzing the nutritional (energy and matter) balance of individual animals and their differential allocation of available nutrients. Digested nutrients are assumed to be utilized for maintenance cost, M; growth, A S; reproduction, R; and dispersion behaviour (including dispersal), D. The simulation model whose main ideas are described verbally is being developed at present. The model is intended to simulate density, age structure, reproductive activity of different categories of the population and spatial distribution; grazing impact apportioned among the most important potential food species (or group); interaction with sympatric rodents, their predators and parasites. Special emphasis is placed on the spatial heterogeneity of the landscape. The population dynamics model is of the Monte Carlo type and considers the realization of a series of events by calculating average probabilities and “drawing” random numbers. The model simulates individual animals in a large heterogeneous area. Qualitative predictions based on our basic hypothesis are discussed and compared with available field information.     

Identifying weather‐related covariates controlling grape berry moth dynamics*

The use of plant protection products requires precise forecasting of the susceptible larval stages of the grape berry moths Lobesia botrana and Eupoecilia ambiguella as these dynamics vary with the weather pattern of a particular year. The objective of this research has been to partition the relative influence of specific climatic factors on the dynamics of these insects. Data taken from 7 years of continuous monitoring of the flight occurrence of male adults, and of the following development stages (i.e. eggs and larvae), was analysed by a generalized Leslie process. The model type reduces the population to three probabilities: development, survival and fertility. Each probability can be modelled as a function of the associated weather factors, while the functional relationships and the model parameters are established. The analysis started with the simplest approach and, in a step‐by‐step procedure, model complexity was added until a sufficient fit to the overall data set was achieved. Within the magnitude of the model, development rates were controlled solely by temperature, but the duration of single stages (i.e. survival) was found to be affected by a combination of temperature and relative humidity. The model represents a combination of mechanisms within a season with empirical components.     

Testing and modelling the potential of three diploid plants in Poaceae as a new pathosystem to investigate the interactions between cereal hosts and cereal cyst nematode (Heterodera avenae)

Cereal cyst nematode (CCN), Heterodera avenae, is one of the most important pathogens of wheat worldwide, and causes significant yield losses. Research on CCN–wheat interactions is hampered by the lack of an effective model pathosystem. This study investigated the potential of the model cereal Brachypodium distachyon (Bd21‐3) and diploid wheat 2A (G1812) and 2D (AL8/78) as model hosts for CCN. Nematode infection analysis showed that although some CCN penetrated Bd21‐3 roots, these nematodes failed to develop to the later developmental stages or form cysts, indicating B. distachyon is not a host for CCN. A strong burst of reactive oxygen species (ROS) within Bd21‐3 roots infected with CCN was induced 3 days after infection and the expression of seven ROS‐producing genes was significantly increased. In contrast, CCN completed its life cycle in both diploid wheat 2A and 2D, and formed normal syncytia in these hosts. Although CCN developmental processes within both diploid wheat 2A and 2D were very similar to those in the susceptible control, the number of cysts formed on diploid wheat 2D was less than those formed on diploid wheat 2A and the susceptible control, indicating that diploid wheat 2A was a more suitable host for CCN than 2D. This is the first report of a potential new pathosystem for CCN–host interactions using diploid wheat.     

Biochemical and molecular characterisation of acetylcholinesterase in four field populations of Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

BACKGROUND: The oriental fruit fly, Bactrocera dorsalis, is a major pest that infects fruits and agricultural products worldwide. The latest resistance monitoring of B. dorsalis from mainland China has identified high levels of resistance to insecticides. In this study, the biochemical and molecular characteristics of acetylcholinesterase (AChE) in four field populations of B. dorsalis are investigated. RESULTS: Among the four populations, the DG population and its purified AChE were found to be the least susceptible to malathion and five inhibitors, whereas the KM population and its purified AChE were the most susceptible. The highest catalytic activity of purified AChE was found for the KM population, and the catalytic activity of the DG population was the lowest. Among developmental stages, the AChE purified from larvae was found to be the most insusceptible to inhibitors, but its catalytic activity was the highest. Sequence analysis of the cDNA encoding AChE showed that some residue differences existed. However, no significant differences in expression levels of the AChE gene among populations and developmental stages were detected. CONCLUSION: The results suggest that the decrease in susceptibility of B. dorsalis was mainly caused by decrease in AChE activity, and they provide a broad view on the relation between AChE and resistance. Copyright © 2012 Society of Chemical Industry     

Zaadbehandeling met D.D.T. tegen de Uienvlieg

Summary Several field-trials in the Netherlands during the season of 1946 proved the effectiveness of a seed-treatment with D.D.T. to control the onion maggotChortophila antiqua Meig. in onions and leeks.The results obtained with D.D.T. were as good as or perhaps even a little better than those with calomel.After coating the seed with glue, the seed has to be stirred with the insecticide.The dose was 20 g D.D.T. on 100g onionseed, applied as 40 g of a D.D.T.-talc powder containing 50% D.D.T. on 100 g onionseed.     

A simulation model for forecasting the timing of attacks of Delia radicum on cruciferous crops1

The cabbage root fly (Delia radicum) is a major pest of cruciferous crops in temperate regions of the world. A model using weather data has been developed to forecast the timing of D. radicum attacks. The model simulates development of a field population of D. radicum, commencing with the overwintering stage (diapause pupa) and following development through the first, second and, where appropriate, third generation until autumn. The model is based on a series of rate equations which describe the relationship between the rate of development of D. radicum and temperature. The model uses soil temperatures in the simulation of the development of the egg, larval and pupal stages, and air temperatures with the adult-fly stage, taking account of periods of summer dormancy (aestivation) and the onset of winter dormancy (diapause). Using local weather data or standard measurements of air and soil temperatures taken at agrometeorological stations, the model can forecast D. radicum activity in any region.     

The impact of phenology,exposure and instar susceptibility on insecticide effects on a chrysomelid beetle population

Direct topical impact of an insecticide spray on a population of a non-target leaf-eating beetle, Gastrophysa polygoni, was studied, and the relative importance of phenology, instar susceptibility and instar specific exposure was evaluated. Two insecticides, cypermethrin and dimethoate, were investigated. In the laboratory, topical toxicity to eggs, second-instar larvae and adults was recorded in dose-response experiments. The spatial distribution of larvae and eggs were measured in the field. Deposition of insecticide onto eggs, second-instar larvae and adult specimens was measured at different positions within the crop canopy by use of a dye tracer technique. A temperature-driven population model was constructed to simulate population development of all life stages in the field. The model was based on laboratory measures of growth and development at various temperatures. Mortality due to direct insecticide exposure was calculated as a function of population demography, spatial distribution of individuals, spatial deposition of the insecticide, and stage-specific susceptibility. Cypermethrin had the greatest impact, reducing population size by 19–32%. The life stages most sensitive to cypermethrin were the larval instars. As the population developed from eggs to larvae and imagines, the impact of one spraying first increased and then decreased according to the proportion of larvae in the population. Dimethoate had less effect on the population, i.e. 1·9–7·6% reduction. Dimethoate was most toxic to the egg stage, and consequently the effect on the population decreased as the proportion of eggs decreased due to hatching. The direct effect of insecticide spraying was significantly affected by all three factors investigated, i.e. phenology, life stage susceptibility and stage-specific exposure. The latter factor is composed of both spray flux at various spatial positions in the canopy and the ability of different life stages to retain spray droplets. © 1998 SCI     

Ecological Studies on the Larger Grain Borer, Prostephanus truncatus (Horn) (Col.: Bostrichidae) and their Implications for Integrated Pest Management

In this article, we review studies of the ecology of the larger grain borer, Protephanus truncatus, both outside and within the maize storage systems. Laboratory studies have shown that P. truncatus can breed on a wide range of woody substrates (branches, roots, and seeds). Pheromone trap catches in different habitats strongly suggest that P. truncatus is well-established in certain non-agricultural environments, presumably breeding in dead or dying wood. In Meso-America, West and East Africa, P. truncatus reproduction in the field has been documented in branches ring-barked by cerambycid beetles. Within a maize store, P. truncatus densities can increase from very small initial colonies of probably less than 200 individuals to densities in excess of 1000 beetles per kg after about 4–6 months of storage. Insect parasitoids are very often found in smallholders' grain stores attacked by P. truncatus, but they do not contribute significantly to population regulation. Declines in maize store population levels in Benin from 1993 to 1996, and in adult abundance in pheromone traps in the natural environment in Kenya, have been attributed to predation by the introduced predator, Teretrius nigrescens, but in recent years pheromone trap catches in West Africa suggest that the situation may be complex. Several environmental factors, notably temperature, humidity, and daylength, and their interactions, have been correlated with P. truncatus flight activity, as well as, in West Africa, the emptying of maize stores. Laboratory experiments have shown food quality also affects flight activity. Factors terminating dispersal and flight are most likely attraction to the male-released aggregation pheromone. Short range attraction to plant volatiles has also been recorded. In Africa the highest densities of P. truncatus tend to occur in humid lowlands, which contrasts with the situation in meso-America where P. truncatus tend to occur in greatest numbers in cooler upland regions. Pheromone trap catches can be significant predictors of the risk of stores becoming infested. Coupled with the development of a rule-based model of flight activity, these studies may offer the prospect of predicting the risk of store infestation based upon temperature and humidity measurements.     

Weed seed rain interception by grass cover depends on seed traits

Weed management requires a better understanding of the dynamics of the weed seedbank, which is a primary source of weeds in a field. Seeds reaching the ground after seed rain replenish the seedbank and therefore contribute to future weed infestations. Our investigation is based on the hypothesis that a permanent vegetation cover, such as a grassland, can prevent weed seeds from reaching the ground. Therefore, we developed an innovative experimental device to simulate in controlled conditions the seed rain of 12 weed species (Capsella bursa‐pastoris, Conyza canadensis, Myosotis arvensis, Papaver rhoeas, Poa annua, Polygonum aviculare, Ranunculus sp., Rumex obtusifolius, Sonchus asper, Stellaria media, Taraxacum officinale and Veronica persicaria). We quantified the interception of weed seeds by a grass cover. Grass cover height, seed size and seed appendage (e.g. pappus, wing or awn) increased seed interception, in contrast to seed weight and shape index. From these results, we established a linear model to predict weed seed interception by a grass cover as a function of their seed trait values. The relationship between the predicted interception and weed community dynamics observed in grasslands was negative for some species, indicating that other processes may be involved depending on weed species. The weed seed interception model will be incorporated into an existing model of weed population dynamics to simulate the impact of grassland insertion into arable crop rotations.     

Assessing the performance against houseflies of indoor aerosol space sprays. Part I. Factors examined during tests with houseflies in free flight

The development of a mathematical model which, by quantifying the interaction of a population of houseflies with an ageing spray cloud, is capable of predicting the knockdown and kill performance of insecticidal aerosol formulations shown against houseflies, Musca domestica L., will be presented in a series of four separate papers. In this first paper, measurements were made of insecticide collected by houseflies during free flight using a standard room-spray technique. With pressure-packed aerosol formulations where the solvent is the principal change, it was shown that both knockdown and mortality responses of the insects were directly related to dose collected. The process of droplet collection was most significantly influenced by their size and availability, dependent upon the time after spraying, the position of insect release and the activity of individual adult M. domestica. The knockdown or mortality response of the insect to given amounts of insecticide was largely unaffected by the remaining solvent, although, with mineral oil, some inhibition was noted at low mortality levels. The amount of insecticide accumulated by houseflies in their initial flight was of prime importance in determining the overall effect. Flies remaining not knocked down at the end of the exposure period were shown to be so because they had accumulated less toxicant and not necessarily because they were more tolerant of the insecticide. The establishment of a relationship between the number of flies in flight and time after release has provided a key function for incorporation into the model.     

Electron microscopy of DNA-cores in nuclear polyhedral viruses

Electron micrographs show the presence of DNA-cores in the virus rods isolated from nuclear polyhedral bodies fromBarathra brassicae, Adoxophyes reticulana andOrgyia antiqua. The DNA-cores in the virus rods are enclosed by virus protein.Samenvatting Na behandeling van kernpolyëders vanBarathra brassicae, Adoxophyes reticulana enOrgyia antiqua met 0,1 N natriumcarbonaat werden met de elektronenmicroscoop de afzonderlijke virusstaafjes (fig. 1A, C, F), alsmede dunnere draad- en staafvormige deeltjes waargenomen (fig. 1B, D, E, G, H). Deze deeltjes stellen het deoxyribonucleïnezuur voor, dat als strengen in het virusstaafje aanwezig is.     

Simulation of insecticide influences on the population dynamics of the Colorado beetle

A weather-based simulation model of population development of Leptinotarsa decemlineata (Colorado beetle) has been extended to include the effects of insecticides. The dynamics of larvae (1st to 4th instar) and the resulting abundance of the adult summer generation has been simulated under the influence of insecticide applications. To describe the mortality caused by different insecticides on the stages of development of L. decemlineata, detailed experimental data are necessary. In this paper, preliminary experience to adapt the SIMLEP computer model to simulate insecticide action on L. decemlineata populations are published for the first time. These investigations aim at developing a more complete model which will be applicable to agricultural practice, not only to predict the dates of density maxima of the developmental stages of L. decemlineata, but also to estimate the need for and the required extent of insecticide applications, i.e. to guarantee optimum results from pesticide treatments.     

Studies on the sorghum grain midge,Contarinia sorghicola Coquillet,in relation to environmental influence

Abstract

Biology, ecology and damage potential of the sorghum midge, Contarinia sorghicola Coquillet, were studied at Coimbatore, India. The life cycle of the midge was shorter in summer than winter: Johnson grass, Sorghum halepense and pearl millet, Pennisetum americanum served as alternate hosts for the sorghum midge. Seasonal incidence studies revealed that four peak infestations occurred in crops sown in April, June, August and October. Midge developmental stages were quite active all through the year with no diapause, Peak adult midge attraction to the light trap was recorded at 21.00 hours. However, adult midges were found to be quite active only in the daytime in the field. There was no relationship between adult midge catches from the light trap and the population recorded in the field. Morning relative humidity and wind velocity were negatively associated with the population of midge attracted to the light trap. An increased percentage of midge population was recorded in the light trap during the new moon and second quarter phases of moon. Sticky traps were not efficient in trapping adult midges. One pair of adult midge per earhead caused 16–9% grain damage.     

基于两性生命表评价取食柑橘木虱对六斑月瓢虫和龟纹瓢虫生长发育及种群的影响

为有效防控重要害虫柑橘木虱Diaphorina citri,在实验室条件下测定取食柑橘木虱后六斑月瓢虫Cheilomenes sexmaculata和龟纹瓢虫Propylea japonica各虫态的发育历期,利用构建的年龄-阶段两性生命表对取食柑橘木虱后六斑月瓢虫、龟纹瓢虫生长发育及其种群参数进行研究。结果显示,取食柑橘木虱后六斑月瓢虫羽化前的发育历期为14.80 d,显著长于取食柑橘木虱后龟纹瓢虫的14.41 d;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫产卵期分别为15.88 d和10.23 d,前者显著长于后者;取食柑橘木虱后六斑月瓢虫净增殖率、内禀增长率和周限增长率分别为25.48、0.10 d-1和1.10 d-1,取食柑橘木虱后龟纹瓢虫净增殖率、内禀增长率和周限增长率分别为14.13、0.06 d-1和1.06 d-1,均低于取食柑橘木虱后六斑月瓢虫;取食柑橘木虱后六斑月瓢虫和龟纹瓢虫的平均世代周期分别为33.87 d和44.95 d,前者显著短于后者。表明取食柑橘木虱后六斑月瓢虫和龟纹瓢虫均能完成整个世代,且六斑月瓢虫种群增长优于龟纹瓢虫,可大规模繁殖六斑月瓢虫,可用于柑橘木虱...     

Studies on morphology and biology of immature stages of the predator Rhyzobius lophanthae Blaisdell (Col.: Coccinellidae)

Morphological characteristics of immature developmental stages of Rhyzobius lophanthae Blaisdell (Col.: Coccinellidae), predator of scale insects of the family Diaspididae (Homoptera), are described. Data about the morphology of eggs, the four larval instars, and the pupa is presented. Larval instars are described in more detail: size of head capsule, length of tibia, distribution of dorsal and lateral setae of abdomen segments for each larval instar is reported. Distribution of spiracles is also given. Study on the biology concerns the influence of prey on the duration of instar periods. The diaspidids Aspidiotus nerii and Aonidiella aurantii were used as food. The mean duration of the developmental period from egg to adult was 27.1 days, and no mortality was observed (0%) when A. nerii was used as prey. The respective numbers when the prey was A. aurantii were 48.8 days and 84%.     

Phenological forecasting model for Cydia funebrana*

A simulation model of the phenology of Cydia funebrana (plum fruit moth) is presented. The Logan function was used to determine the temperature‐dependent developmental rates of the eggs, larvae and pupae; a linear equation was used for the ageing rate of females. The mean fecundity of females as a function of age was expressed by a modified Bieri's function. In order to simulate the stochastic process, a time‐distributed delay model was used. Results from the validation of the model in northern Italy (1995 and 1997) are reported. Catches of male moths in pheromone traps and oviposition activity were monitored in orchards of mid‐ and late‐ripening plum cultivars. The model was then run using temperature data from each farm. When the oviposition activity forecast by the model was compared with that actually observed in the orchards, good correlations between actual and forecast oviposition were obtained. The model is already available for technicians in Emilia‐Romagna and is a valuable tool in integrated fruit production; it gives an indication of the right moment to apply insecticides or to carry out further monitoring activity to assess the risk of C. funebrana damage (e.g. by sampling actual oviposition on just a single occasion).     

Population dynamics and biological control of European grapevine moth (Lobesia botrana: Lepidoptera: Tortricidae) in Albania using different strains of Bacillus thuringiensis

This work describes the results of an experiment conducted in a vineyard in Durres, Albania from 2004 to 2006, to study the efficacy of two strains of Bacillus thuringiensis Berliner, vars kurstaki and aizawai, against the moth Lobesia botrana Denis & Schiffermüleler (Lepidoptera: Tortricidae), a major pest of grapevines. The experimental results revealed that the two strains were significantly more effective than the control, with var. aizawai being more effective than var. kurstaki. Bacillus thuringiensis (Bt) provided better protection of the bunches from the second generation compared to the third one showing the short persistence of action of the active ingredient. The high degree of efficacy supported a role for Bt in grapevine moth management. Our study also provided insights into the population dynamics of the European grapevine moth under Albanian climatic conditions. Despite the necessity for the pheromone traps to indicate the start of the flight period, the experiments confirmed the lack of a correlation between the population dynamics and the level of damage by the pest. Pheromone trapping can offer very useful indications regarding the start of the flight period of each generation and its duration but not on the severity and incidence of the pest.     

Identification of economically important Liriomyza species by PCR‐RFLP analysis*

Only adult males of Liriomyza bryoniae, L. huidobrensis, L. sativae and L. trifolii can be identified with certainty on basis of their genitalia. Female adults, pupae and larvae can only be identified on the level of groups of species (L. bryoniae and L. huidobrensis vs. L. sativae and L. trifolii). Species identification in all developmental stages is possible using molecular biological techniques. Our method is a PCR amplification of a 790‐bp fragment of mitochondrial cytochrome oxidase II (COII) DNA followed by RFLP analysis. The method was tested on single larvae, pupae and adults and proved to be applicable to these three life stages. The specificity of the assay was assessed by comparing the results of the PCR‐RFLP analysis with those of morphological analysis using 60 Liriomyza specimens. Molecular and morphological identification agreed for all specimens analysed. PCR‐RFLP is a powerful diagnostic tool for rapid and reliable identification of all life stages of economically important Liriomyza species.     

群居型和散居型亚洲小车蝗成虫能量代谢相关酶活性测定

为明确亚洲小车蝗Oedaleus asiaticus成虫飞行肌对其体内能源物质利用的情况,采用室内生化法测定能源物质代谢相关5种酶,即3-磷酸甘油醛脱氢酶(glyceraldehyde phosphate dehydrogenase,GAPDH)、3-磷酸甘油脱氢酶(glycerol-3-phosphate dehyd...