稻田蜘蛛混合种群空间分布模式动态分析(英文)

结果表明,在东方红农场稻田中总共有11科29属43种蜘蛛,其中早稻田中有8科19属43种,晚稻田中有10科27属36种。在水稻的不同发育阶段蜘蛛混合种群的空间分布模式存在差异。在早稻发育的前期、中期和后期,稻田蜘蛛混合种群的空间分布模式分别是聚集的、随机的和聚集的;在晚稻发育的前期、中期和后期,其空间分布模式依次是均匀的、聚集的和均匀的。同时,对其空间分布模式动态进行了初步分析。     

黑颈鹤种群动态模型

本研究据已收集到的数据,用非参数统计方法确定了黑颈鹤种群的性比为1:1,避免了大量取样。根据黑颈鹤的特点,我们将其种群分成4个年龄组,并求出了各年龄组的存活率和繁殖率,据此建立了描述黑颈鹤种群动态的数学模型。用模型计算得出在乌蒙山区越冬的黑颈鹤种群的自然增长率为1.85‰;理想的种群结构为幼鹤、亚成鹤、成鹤、老鹤分别占总数的15.5％、21.5％、60.2％、2.8％,最后预测了乌蒙山黑颈鹤种群在1988～2000年越冬期的数量。1989年1月经实地调查该种群总数为310只,而预测值为303只,误差约2％。     

GROWTH, REPRODUCTION AND FIELD POPULATION DYNAMICS OF FRANKLINIELLA BISPINOSA (THYSANOPTERA: THRIPIDAE)

Abstract Frankliniella bispinosa was reared at five constant temperatures using pollen of Typha domingensis as food. At 15°C, 37.5 days are required for completing the life cycle and the adult females survived for about 30 days. The immature stage and the female longevity were significantly reduced when temperature increased and they were only 9.2 and 3.9 days, respectively, at 35°C. The maximal number of eggs (123.2/female) were laid at 25°C, as compared with 29.5, 42.1, 11.6 eggs per female, respectively, at 15°C, 20°C and 30°C. F. bispinosa occurs on Bidens pilosa flowers all the year round in south Florida. However, the population is more abundant from mid-March to early April.     

花蓟马Frankliniella bispinosa的生长繁殖特性及种群动态研究(英文)

本文提出一种用香蒲 (Typhadomingensis)花粉饲养花蓟马 (F .bispinosa)的方法 ,恒温饲养表明 ,在1 5℃时 ,该蓟马的世代历期长达 3 7 5d ,雌成虫平均寿命为 3 0d ;在 2 0℃和 2 5℃恒温下 ,世代历期分别为1 8 9和 1 3 8d ,雌成虫寿命分别为 2 9 0和 2 3 3d。平均产卵量在 2 5℃时达到最高 (1 2 3 2头 雌 ) ,而在其他几种恒温下产卵量显著减少。在佛罗里达南部 ,终年可见该蓟马在鬼针三叶草 (BidenspilosaL .)花上发生 ,而种群高峰期在三月中旬到四月初 ,平均每朵花中蓟马成虫数最高时可达 48 7头。     

负二项分布与昆虫种群空间格局分析的研究现状

对农业有害生物及其天敌种群密度的正确估计是实施IPM(有害生物综合治理)方案的先决条件,因此,抽样方法一直被列为昆虫学,生态学和植物保护科学中最重要的基本     

褐飞虱种群动态的模拟模型(英文)

本文根据种群生命系统的概念和分析,组建了模拟褐飞虱(Nilaparvata lugens St(?)l)种群动态的计算机模型。该模型包括一个多列矩阵和一组差分方程。多列矩阵用于描述褐飞虱种群的龄期重叠现象及其年龄——虫态结构;差分方程用于计算种群的增长过程。在建模时,我们把10日度作为褐飞虱发育的一个年龄,用天作为模拟的时间步长,同时利用了褐飞虱特定龄期的发育速率,根据生命表数据计算的特定龄期存活率、长翅型成虫的迁飞类型及数量、雌成虫的生殖力等有关资料。经过采用福建省龙海、福州和沙县三个地方1896—1990的实际观测资料与模型的预测结果进行比较,验证了该模型的有效性和准确性;通过改变模型的主要输入变量,得到了各种不同的输出结果,由此对模型的行为及真实性作了分析。笔者认为该模型可用于进一步研究褐飞虱的生物学、生态学以及综合治理的基础,稍作改进,也可用于描述其它昆虫的种群生命系统。     

小叶章种群高度的季节动态

探讨了三江平原以小叶章为优势种的典型草旬、沼泽化草甸、沼泽３个植被类型中小叶章种群高度的变化规律。结果表明,在３个类型中,种群高度的季节动态均呈单峰型,极大值均出现在７月末,分别为１１２．６７ｃｍ、１０１．６１ｃｍ、８３．８８ｃｍ。ＨＡＧＲ的季节动态在７月末之前〉０,之后〈０;典型草甸和沼泽化草甸的极大值出现在６月末至７月中旬,沼泽则出现在６月中旬至６月末;极小值典型草甸出现在８月末至９月中旬,而     

A COMPUTER SIMULATION MODEL OF POPULATION DYNAMICS OF BROWN PLANTHOPPER, NILAPARVATA WGENS STÅL

Abstract A comprehensive computer model, based on the concept and analysis of the population life system, was developed to simulate effects of major environmental variables on the population dynamics of brown planthopper (BPH), Nilaparvata lugens Still. The basic frame of the model consists of a multiple column matrix, which was used to describe the stage overlapping phenomenon and the age-stage-structure of the BPH population, and a set of difference equations, which was employed to calculate the growth of individuals from one age-class and stage to the next in the BPH population. The life cycle of BPH was incremented in the model into 10 degree-days age classes and simulations were run with daily time steps. The model incorporates 1) temperature-dependent developmental rates or eggs, nymphs, and adults; 2) stage-specific survival rates obtained from the life table data of BPH; 3) immigration patterns and rates of macropterous adults; and 4) female fecundity. General validation of the model was established by comparisons between simulated and observed population densities for five years at three locations, which represent plain, hilly, and mountainous aresa in Fujian Province, using actual daily weather data and immigration patterns of macropterous adults for each year as model inputs. Simulation results from the model output were also compared by varying the model inputs within realistic limits in order to analyze the model behavior. We think that this model may serve as the framework for further studies on biology and ecology of BPH, and used to study various integrated BPH management strategies. Moreover, this model could be adapted to describe the population life systems of other insects with minor modification.     

THE POPULATION DYNAMICS OF NORTHERN SEA LIONS, 1975-1985

Abstract: Populations of northern sea lions ( Eumetopias jubatus ) in the vicinity of Marmot Island, Alaska declined during 1975–1985 at about 5% per year (Merrick et al. 1987). The cause of this decline is not known. A life table for the northern sea lion was calculated assuming that life spans follow a Weibull distribution. Samples of northern sea lions taken in the vicinity of Marmot Island, Alaska during 1975–1978 and 1985–1986 indicate that the average age of females older than 3 yr increased about 1.55 yr (SD = 0.35 yr) while the population was declining at about 5% per year. Fecundity rates decreased by 10% over the same period, but the decrease was not statistically significant (Calkins and Goodwin 1988). Possible causes of the population decline and the change in age structure were examined by writing the Leslie matrix population equation in terms of changes in juvenile and adult survival rates and fecundity, and examining the short–term behavior of the trajectories of the average age of adult females, total number of females, and total number of pups with respect to those changes in the vital parameters. From the observed rate of declines of adults and the changes in average age of adult females and fecundity, estimates of the changes in adult and juvenile survival were calculated; estimates of the standard deviations of these changes were estimated via a bootstrap procedure. One purpose of this exercise is to aid in setting priorities for research for determining the cause of the decline. An explanation for the observed declines in numbers of adult sea lions consistent with the observed fecundity rates, a rate of decrease of 5% in the number of adults, and the corresponding increase in average age (of females age 3 yr and older) was a 10%–20% decrease in the survival of juveniles (age 0-3 yr) coupled with an insignificant change in adult survival (0.03%, SD = 1%).     

EFFECTS OF HOST PLANTS ON POPULATION DYNAMICS OF LIPAPHIS ERYSIMI (KALT.) IN THE FIELD

Abstract The population dynamics of alates and apterous of turnip aphid (TA) Lipaphis erysimi (Kalt.) together with the incidence of parasitism by Diaeretiella rapae (M'Intosh) on five host vegetable varieties in the field were evaluated. The results showed that the average populations of TA apterous on host vegetable varieties turnip, Chinese kale, leaf mustard, flowering cabbage and Chinese cabbage were 63. 425, 10. 041, 24. 928, 23. 323 and 114. 308 aphids/plant, respectively. The 'critical day' was used to estimate the date when TA population density on host vegetable varieties reaches its economic threshold. The relationship between TA apterous population ( x ) and mummy aphids parasitized by parasitoid D. rapae was significant, and the regression formula is y = 0. 1211 + 0. 01431 (r=0. 9739**).     

PHYSIOLOGICAL AND POPULATION ECOLOGY OF INTERTIDAL AND SUBTIDAL ASCOPHYLLUM NODOSUM (PHAEOPHYTA)1

Morphological, demographic and physiological characteristics of Rhode Island intertidal and subtidal populations of Ascophyllum nodosum (L.) Le Jolis were compared in order to examine factors influencing vertical distribution. The two populations had distinctive morphologies: subtidal plants were narrower (more terete) and highly branched compared with intertidal plants. The subtidal population showed signs of necrosis and breakage, which was reflected in significantly shorter mean plant size. High survivorship and low recruitment of both population resulted in relatively constant densities, averaging 91 and 50 plants per m² in the intertidal and subtidal habitats, respectively. Intertidal plants had higher mean annual growth rates (25 cm.yr^?1) than subtidal plants (2 cm.yr^?1). In general, intertidal plants had higher photosynthetic capacity and nutrient (NO₃^?) uptake rates than the subtidal population but maintained lower light-harvesting pigment and tissue nitrogen concentrations. Although Ascophyllum nodosum is capable of survival and growth in subtidal as well as intertidal areas, results of this study suggest that different selective pressures affect persistence in each habitat. The scarcity of plants in the subtidal environment may be due to the lack of a critical balance between algal production, allocation of photosynthate, and the negative effects of grazers or competitors.     

SEASONAL PATTERNS OF MORPHOLOGICAL VARIABILITY IN SARGASSUM POLYCERATIUM (PHAEOPHYTA)1

Temporal variability in certain morphological and taxonomically important features was quantified for Sargassum polyceratium Mont. from a population in the Content Keys, Florida (U.S.A.). Patterns of blade development, senescence, and loss caused pronounced seasonal changes in blade length-width ratios. Blade length and width were maximal early in the growing season (August-November) and decreased as the annual stems matured. Early in the growing season, plants had broader blades with randomly distributed cryptostomata. Late in the growing season (February-April), plants had more linear blades with cryptostomata approximately arranged in two rows, one on each side of the midrib. The length-width ratio of blades increased acropetally along the stems and were directly correlated to the size of the cryptostomatal opening and inversely correlated with the number of cryptostomata. The branching pattern of the annual stems ranged from short spur branches to well-developed, lateral axillary branches. The frequency of bifurcated blades increased significantly late in the growing season. Vesicle shape and size and pedicel length were temporally stable. Alated pedicels and mucronate vesicles occurred in low frequencies. The variability of the morphological features used to delineate species within the genus Sargassum on the tropical eastern coasts of the Americas is poorly understood.     

PREMATURE CHROMOSOME CONDENSATION OF THE KARYOGAMY-BLOCKED SPERM PRONUCLEUS IN THE FERTILIZATION OF FUCUS DISTICHUS (FUCALES,PHAEOPHYCEAE)1

Mitosis of egg and sperm pronuclei of Fucus distichus subsp. evanescens (C. Agardh)Powell was examined by fluorescence and electron microscopy when migration of the sperm pronucleus and, as a result, karyogamy were blocked by colchicine treatment after plasmogamy. Chromosome condensation was obsewed in both pronuclei Microspectrophotometric studies after staining the nuclei with mithramycin A clearly showed that DNA synthesis ocurred in the egg pronucleus but not in the sperm pronucleus. This means that chromosomes condensed prematurely in the sperm pronucleus (premature chromosome condensation). In some cases, the egg chromosomes became arranged on a metaphase plate, whereas the sperm chromosomes lay scattered near the egg pronucleus. Immuno fluorescence microscopy using anti-β-tubulin antibody confirmed that a normal spindle was formed at the egg pronucleus. A pair of centrioles existed at the two poles of this spindle. The sperm nuclear membrane disappeared, and microtubules radiated to the sperm chromosomes from one pole of the egg spindle.     

SECRETION OF PHENOLIC SUBSTANCES INTO THE ZYGOTE WALL AND CELL PLATE IN EMBRYOS OF HORMOSIRA AND ACROCARPIA (FUCALES, PHAEOPHYCEAE)

We have used light and electron microscopy to study the secretion of phenolic substances into the primary walls and cross walls of zygotes and embryos of the brown algae Hormosira banksii (Turner) Decaisne (Hormosiraceae) and Acrocarpia paniculata (Turner) Areschoug (Cystoseiraceae). Phenolic compounds packaged within physodes are a major cytoplasmic component of brown algae. Physodes accumulate at the zygote periphery early in development and are secreted into the primary zygote wall. At germination, physodes accumulate at the rhizoid tip. The first sign of impending cytokinesis is the lining up of these phenolic vesicles in the plane of cell division. This precedes the arrival of other wall constituents. Physodes, together with other wall components, contribute to the development of the cell plate. We conclude that phenolic compounds play an important role in cell-wall construction in these species.     

BIOLOGY AND POPULATION DYNAMICS OF A CREVICE-DWELLING LANDSNAIL, CRISTATARIA GENEZARETHANA (CLAUSILIIDAE)

Crevice-dwelling land snails emerge only infrequently to theexposed surface, and very little is known about their naturalhistory. Here we report on the biology, life cycle, populationdynamics and longevity of one such species, Cristataria genezarethana,which we studied over a period of three years. C. genezarethana spends 95–98% of its lifetime withinrock crevices. In winter the crevice serves as an egg layingsite, and as a retreat during periods of inactivity. Throughoutsummer it serves for aestivation adults aestivate near CTeviceopenings, young apparently deeper inside. The surface of the rock serves mainly as a lichen-feeding andcopulating site, to which the snails emerge during brief periodsof activity. Both for the onset and for the continuation ofits activity season, C. genezarethana is absolutely dependentupon rain. However, activity ends before the end of the rainyseason, suggesting that aestivation is not merely a direct responseto dry climate. Though the population as a whole was active on each rainy day,no more than 15%–20% of the population were active simultaneously.An individual snail was active, on average, for only 6–12days per year. Population size of the study-rock reached 2000–2900individuals, and mean density was 150–200 snails m². Thissnail carrying capacity of the rock is broadly similar to thatof densely populated bushy habitats (when snail weight is considered).In these dense populations, low mating frequencies and growthinhibition may regulate population size. In all three seasons, the population consisted of two main large,well defined age groups: adults and young. As compared to theadults, the young were active on different parts of the rockand at different times. Although a third, intermediate groupof sub adults was found, it was always very small. A fourthgroup, of juveniles, appeared during winter; later, most ofthem disappeared. We did not observe any shift from the young to the adult sizegroup. This suggests a broadly stable population, with virtuallyno recruitment, in which final growth to adulthood is inhibitedby the adults. Growth was very slow, suggesting that maturityin nature is reached in about 11 years, and that individualslive sixteen years at least. Mortality occurred in all age groups,and about 5% of the population died each year. There was noevidence for heavy predation. Crevices might be a suitable habitat for land snails in whichthe hatching period, and period of juvenile growth, are verylong. (Received 1 February 1993; accepted 27 March 1993)     

SEXUAL ISOLATION BETWEEN A EUROPEAN AND AN AMERICAN POPULATION OF ECTOCARPUS SILICULOSUS (PHAEOPHYTA)1

Sexual plants of Northeastern American Ectocarpus siliculosus (Dilhw.) Lyngb. have been isolated and cultured. Female gametes produce a volatile sex hormone acting on male gametes. Combination of American and European gametes shows that the initial step of the sexual reaction (attraction of male gametes) works normally, whereas interaction of cell surfaces and fusion of gametes is prevented.