Life Tables for the Experimental Population Phenacoccus solenopsis Tinsley at Different Temperatures

[Objective] The study was to investigate the effect of temperature on pop- ulation dynamics of Phenacoccus solenopsis Tinsley, so as to providing references for the control and prevention of this pest. [Method] The experimental populations were kept in laboratory and fed on cotton plants, and the major parameters of the population were recorded. [Result] By the construction of age specific life tables and reproductive life tables for the P. solenopsis experimental population at 24, 27, 30 ~C, more than 10 parameters were obtained, including mean generation time, survival rates of different stages and sexes, life expectancy, spawning period, fecundity amount per female, sexual ratio, net reproductive rate, intrinsic increase rate, finite increase rate, population trend index, curve of survival rate, and curve of daily fe- male oviposition, which revealed the effect of temperature on growth and develop- ment, life expectancy and fecundities of P. solenopsis. [Conclusion] The reproductive potential of the P. solenopsis population is very great at suitable temperature, making it easy to outbreak. The research provided scientific basis for population dynam- ics investigation, predication and integrated control of P. solenopsis.

Effects of temperatures on the development and reproduction of the armyworm, Mythimna roseilinea: Analysis using an age-stage, two-sex life table

The armyworm Mythimna roseilinea（Walker） is a major pest of grain crops in South China. So far little is known about its basic biology and ecology, making prediction of population dynamics difficult. This study examined the relationships of individual development and population growth with temperature based on an age-stage, two-sex life table of M. roseilinea reared on maize in the laboratory at 18, 21, 24, 27 and 30℃. The highest values of net reproductive rate（R_0） and fecundity were observed at 21 and 24℃, respectively. Both the intrinsic rate of increase（r） and finite rate of increase（λ） increased significantly and mean generation time（T） decreased significantly with increasing temperature. M. roseilinea was able to develop, survive and lay eggs at all temperature regimes tested. Development rates of the egg, larval, pupal, as well as the whole pre-oviposition stages had a positive linear relationship with temperature. The calculated development threshold temperatures of egg, larval, pupal, pre-oviposition and total pre-oviposition stages were 13.29, 8.39, 14.35, 7.42, and 12.24℃, respectively, and their effective accumulated temperatures were 63.59, 445.00, 211.11, 89.02, and 698.95 degree-days, respectively. These results provide insight into temperature-based phenology and population ecology of this insect pest and will allow population prediction and management available in the field.

THE POSSIBILITY ANALYSIS OF NATURAL POPLAR-BIRCH FOREST RECOVERY TO BROAD-LEAF KOREAN PINE FOREST THROUGH THE METHOD OF LIFE TABLE IN THE XIOAXING'AN MOUNTAINS

The basic principle of life table method is deseribed, and the method of tree height instead of tree age in static life table is suggested, and it is also discussed that the possibility of natural poplar -birch forest recover to broad-leaf Korean pine forest on low pitches in the Xiaoxing'an Mountains by this method. If there is no particular situation, Korean pines after high than 5m under natural Poplar-birch forest will basically survive and make their way into dominant callopy accompanied by climax broad-leaf species.

Effects of Aschersonia aleyrodis on the life table and demographic parameters of Bemisia tabaci

The present study reports the sublethal effects of the entomopathogenic fungus, Aschersonia aleyrodis（Webber） on Bemisia tabaci（Gennadius）（Homoptera： Aleyrodidae）. A fungal suspension of A. aleyrodis isolate Aa005 containing 1×107 conidia mL^-1 was sprayed against B. tabaci on eggplant leaves under greenhouse conditions. The effects of fungal application on survival as well as life table parameters of the whitefly were observed at different post inoculation periods. The results indicated that A. aleyrodis can significantly affect the survival of 1st, 2nd, and 3rd nymphal instars of B. tabaci. Developmental periods of different instar nymphs were not affected by fungal application. A. aleyrodis spores persisted well and significantly affected the survivorship of young instar nymphs of B. tabaci at different post incubation periods. Life table results suggested that A. aleyrodis has no impact on general fecundity and longevity of B. tabaci. When the pathogen was exposed to the open environment and maintained for a relatively longer period, a reduction in the reproductive rate and intrinsic rate of increase was caused by the fungal spores, though the sublethal effects were not as good as the control treatment. The results suggest that the ability of spores to suppress an increase in whitefly population persists well after incubation of spores to the external environment（up to 9 days）.

Life Table of Natural Population of Gastrolina depressa

[Objective]The paper was to understand the population development regularity of Gastrolina depressa in natural environment in Guizhou Province.[Method]The population dynamics of G.depressa was studied by establishing life table of natural population of G.depressa via field observation and calculating dynamic trend index of population.[Result]The mortality rates in egg stage,pupal stage and adult stage accounted for 26.42%,10.96%and 8.22%of the total mortality rate,respectively.The mortality rate in larval stage was the highest,accounting for 54.40%of the total mortality rate,higher than the total mortality rate in the other three stages.The population dynamic trend index I=9.25,I>1 indicated that the population showed an upward trend.[Conclusion]Under the natural conditions,the population of G.depressa shows upward trend,and human intervention is needed to control the population.The larval stage is the weak stage of the insect,which is the best time to control the insect.

Positive Stable Frailty Approach in the Construction of Dependence Life-Tables

Dependence may arise in insurance when the insureds are clustered into groups e.g. joint-life annuities. This dependence may be produced by sharing a common risk acting on mortality of members of the group. Various dependence models have been considered in literature; however, the focus has been on either the lower-tail dependence alone or upper-tail dependence alone. This article implements the frailty dependence approach to life insurance problems where most applications have been within medical setting. Our strategy is to use the conditional independence assumption given an observed association measure in a positive stable frailty approach to account for both lower and upper-tail dependence. The model is calibrated on the association of Kenyan insurers 2010 male and female published rates. The positive stable model is then proposed to construct dependence life-tables and generate life annuity payment streams in the competitive Kenyan market.

Fitness of fall armyworm,Spodoptera frugiperda to three solanaceous vegetables

The fall armyworm(FAW),Spodoptera frugiperda Smith(Lepidoptera:Noctuidae)is an important agricultural pest that invaded China in the middle of December 2018.As a polyphagous pest,FAW is identified as a serious threat to agricultural production and food security in China.Pepper(Capsicum annuum L.),tomato(Solanum lycopersicum Mill.)and eggplant(Solanum melongena L.)are three of dominant solanaceous vegetables of this country.To our knowledge,the effects of these plants on the performances of FAW have not been well studied.In this study we assessed the fitness of this pest to these three plants.Results showed that FAW can complete its life cycle when fed with tomato and pepper,but not on eggplant.The population parameters of FAW fed with maize(Zea mays L.)and the three solanaceous vegetables were compared using the age-stage,two-sex life table method.Developmental duration was significantly different in the larval stage,but not in the pupae stage.FAW fed with pepper had the longest pre-adult period(41.73 d)and the lightest pupal weight(0.1134 g);the survival rate was lower than FAW fed with tomato.Significant differences were observed in the mean fecundity of female,with the highest(943.95 eggs)laid by FAW fed with tomato.FAW had the shortest mean generation time(T),the highest intrinsic rate of increase(r)and finite rate of increase(λ)on maize,and the highest net reproductive rate(R_(0))on tomato.Overall,FAW fitness on the three solanaceous vegetables was:tomato>pepper>eggplant.This study provides the foundation for further assessment of FAW risk to solanaceous vegetables and for establishing corresponding control strategies in China.

五普以来中国及其分地区死亡漏报模式变迁

我国历次人口普查的死亡数据质量备受关注,尤其是不同地区的死亡漏报问题,长期以来对公共卫生政策、社会老龄化应对策略以及经济规划存在深远影响。然而,现有研究对分地区、分年龄段死亡漏报的纵向分析仍然较少,特别是在五普至七普期间中国社会的快速转型背景下,死亡漏报模式是否发生变化尚需深入探讨。文章基于对数二项模型和各级政府公布的死亡相关数据,修订五普至七普间各省、自治区及直辖市的死亡数据,系统分析死亡漏报的变动模式及其背后的潜在影响机制。研究发现全国婴儿死亡漏报率自五普以来呈显著上升趋势,从7.04%升至六普的70.99%以及七普的75.67%。但婴儿死亡漏报数量在七普时已显著减少,每十万人漏报从六普的931人降至七普的474人,婴儿死亡数据质量已有所改善。相比之下,成年段与老年段的死亡漏报问题持续恶化,成年段死亡漏报率从五普的5.28%升至七普的26.18%,漏报数量从每十万人674人增加至2 230人;低龄老年段(60~79岁)死亡漏报率从五普的6.21%增至七普的22.64%,漏报数量从每十万人348人增加至920人;高龄老年段(80~99岁)漏报率从1.09%升至4.84%,漏报数量从每十万人108人增加至475人。分地区观察显示各地漏报的严重程度和年龄段侧重存在显著差异。婴幼儿死亡漏报率在华北和东北地区较高;成年段死亡漏报在华北、华东和西北地区尤为严重;低龄老年段漏报以西南、华南地区最高,而高龄老年段漏报则以华南和东北地区最为显著。进一步分析显示不同年龄段的漏报机制存在显著差异。婴幼儿死亡漏报率与其死亡水平之间存在显著的“U”型关系,即死亡率较低时漏报率反而升高,体现出低死亡水平下的统计敏感性的增强;成年段漏报与人口流动密切相关,流动人口参与度对漏报率有负向影响,表明外出人口死亡后返回原籍登记减少了漏报,流动人口能见度则对漏报率有正向影响,反映了流入地因流动人口返乡报告导致的漏报增加;老年段死亡漏报则更多受经济发展水平的影响,但与婴幼儿、成年段有较大不同,其漏报可能与社会经济条件、文化观念和社会支持系统间存在复杂的耦合关系。文章揭示了中国及其分地区死亡漏报模式变迁的基本图景,强调在评估死亡漏报时应结合中国社会的快速转型背景,而非仅依赖静态数理模型。未来研究需特别关注成年段和老年段死亡漏报问题,探索更具针对性的评估和干预策略。

福建古田会址风水林小叶红豆种群结构与动态特征

对福建省古田会址风水林77个样方中的珍稀濒危植物小叶红豆(Ormosia microphylla Merr.et H.Y.Chen)种群进行调查,对其种群结构和动态特征进行分析。结果表明:77个样方中共有小叶红豆273株,根据株高(h)和胸径(DBH)可分为10个径级,其中Ⅰ(h≤50 cm)级的幼苗个体最多(112株),但从Ⅰ级到Ⅱ(50 cm<h≤100 cm)级死亡率为60.7%,表明幼苗的个体生存能力差;幼树至小树阶段(Ⅱ级至Ⅴ级(10 cm≤DBH<15 cm))生长情况较为平稳,从中树至大树阶段(Ⅵ(15 cm≤DBH<20 cm)级至Ⅹ(DBH≥35 cm)级)仅有少数个体能够存活,个体数总体逐渐减少;从高度级结构看,小叶红豆种群在7个高度级均有个体分布,具有一定的完整性和稳定性。小叶红豆种群的动态指数(V pi)为40.67%,随机干扰动态指数(V pi′)为1.36%,随机干扰风险概率(P max)为3.33%,表明小叶红豆种群为增长型种群,但增长不明显,抗干扰能力较弱。小叶红豆种群存活曲线趋向于Deevey-Ⅱ型的B 1亚型;随着径级增加,小叶红豆种群整体生存率函数(S(t))呈降低趋势,而累积死亡率函数(F(t))则呈升高趋势,小叶红豆种群死亡密度函数(f(t))和危险率函数(λ(t))从Ⅳ(5 cm≤DBH<10 cm)级至Ⅴ级明显升高,反映种群有向衰退方向发展的趋势。时间序列预测结果显示:总体上看,经过未来2、4、6、8径级时间后,小叶红豆种群各径级个体数均有增加,种群发展潜力较好。综合研究结果显示:小叶红豆种群整体上呈现增长趋势,但稳定性和抵抗性较弱,小叶红豆自身抗干扰能力弱以及在资源竞争过程中处于劣势是限制小叶红豆种群增长和种群稳定性差的主要原因,建议采取就地保护的同时,通过适当疏伐和施肥以及加强种子培养等手段增加个体数量,提高种群的竞争力和稳定性。

New Characteristics of Active Life Expectancy of the Elderly in China

Life expectancy of the elderly is a significant problem in China, and it changes not only the health care, but also the pension. This study used tracking data from the Chinese Urban and Rural Elderly Population Survey to calculate the age-specific Active Life Expectancy (ALE) of the Chinese elderly population aged 60 years and over. For analysis, this population was divided into different sub-populations according to gender, census register and region. The main conclusions of our study are as follows: 1) The quality of life for elderly males may be greater than that for elderly females;2) There were significant differences in Active Life Expectancy (ALE) and Inactive Life Expectancy (ILE) between urban and rural elderly;3) The differences in ALE between the eastern, central and western regions of China were not significant;and 4) The increased remaining life expectancy of the elderly was mainly attributed to the extended ALE in the lower age group and the expanded ILE in the higher age group. This study expands the knowledge of Chinese elderly’s life expectancy in different health status.

Analyses of Numerical Responses and Main Life Parameters for Determining the Suppression of Amblyseius cucumeris on Panonychus citri

In this paper, the numeral response and main parameters of experimental population life table were analyzed for determining the suppressing ability of Amblyseius cucumeris on Panonychus citri. The result showed that: (1) Under 21-31°C and 1 - 9 prey densities/leaf fragment condition, the prey consumptions of A. cucumeris increased with the temperature or prey density; (2) In 1:3 predator-prey ratio treatment, the suppression of P. citri (Ro=34.0053; T=19.4369; t=3.8204) was rather weak, it was enhanced as the ratio over 5:30, and the populations of P. citri in these treatments can be fully controlled within 4-5 days; (3) Under 25±1°C, 80-85% RH and 15L: 9D illumination conditions, the net reproductive rate, mean generation duration and the time for population double increase of P. citri (Ro=34.0053; T=19.4369; t=3.8204) were higher than those of A. cucumeris (Ro=21.8750; T=16.8943; t=3.7954). While the intrinsic rate of increase and finite rate of increase of the former (rm=0.1814; λ=1.1989) were lower than those of the latter (rm=0.1826; λ=1.2004). These results indicated that A. cucumeris is a desirable bio-control agent to suppress P. citri at lower population stage in citrus orchard.

Life Annuities Calculation in Algeria： Continuous Time Approach

The present paper aims to show the impact of continuous time calculation on life insurance pricing and reserving in the Algerian context. The discrete time approach allows insurance companies to facilitate calculation process but with less accuracy. This approach implies constancy of death quotients during a year. However, the death risk is a continuous function in time. For more accuracy and equity in pricing, calculation needs to consider the exact dates of different payments and also a continuous capitalization process. This gives more adequate premium with fewer hypotheses. This work shows how insurers can propose more adequate pricing using the same actuarial life table.

Development and Reproduction of Sweet Potato Whitefly Bemisia tabaci (Homoptera;Aleyroididae) on Four Vegetable Crops in Southern Sierra Leone

Bemisia tabaci is a polyphagous herbivore that feeds on a wide range of horticultural and ornamental crops cultivated under diverse ecological zones. In Sierra Leone, B. tabaci is found to infest a wide range of vegetable crops by directly feeding on phloem sap thereby inducing physiological disorders, and also serve as a vector to gemini viruses. Invariably the destructive feeding of B. tabaci affects the productivity and aesthetic values of vegetables and other horticultural crops and hence is considered a serious economic pest. A bioassay experiment was carried out by rearing B. tabaci populations on four vegetable crops under controlled laboratory conditions to determine its life table and demographic parameters. Results showed that the intrinsic rate of growth which measures the population size and growth pattern was highest for populations reared on tomato crops with the following values: rm 0.145 female female−1 day−1, the gross reproduction rate (Ro), and finite growth rate λ were highest for population reared on tomato, correspondingly the development period from egg-adult emergence was shortest with a value of 26 d. Conversely, the computed demographical parameters rm, λ and Ro for the population reared on sweet pepper were 0.106 female female−1 day−1 respectively, with a corresponding development period egg-adult emergence as 36d. The computed biological parameters for okra and garden egg varied with intermediary values between tomato and pepper host materials. The survivorship rates were quite significant for the smaller instars (Instars 1-III) with over 80% surviving to pre-pupa and pupa stage for the populations reared for all the test materials. High mortality was noticed for the pre-pupa and pupa stages as their survival rates were significantly low compared to the high survival rates of the smaller instars. Less than 50% of pupae failed to emerge to adults except for populations reared on tomato test materials where 52% emerged to adults. The study indicated tomato as the most suitable host among the four vegetable crops. Although life table and demographic parameters are invaluable information for forecasting pest populations and help in designing pest management efforts, further investigations such as the economic threshold and economic injury levels of B. tabaci population are requisite decision tools for sound pest management decisions of B. tabaci on these vegetable crops. The information obtained from this investigation would be quite relevant for extension service and pest management practitioners where mixed vegetable farming is a common practice.

江苏宝华山宝华玉兰种群结构与动态特征分析

为了揭示极危(CR)植物宝华玉兰〔Yulania zenii(W.C.Cheng)D.L.Fu〕野生种群的结构和动态特征,对江苏省句容市宝华山宝华玉兰野生资源进行全面调查,并运用静态生命表、存活曲线和生存分析等方法综合分析宝华玉兰种群结构和动态变化。结果表明:宝华山全境现存宝华玉兰野生开花植株115株,主要分布于宝华山北坡中部。宝华玉兰种群以中树和大树〔10 cm≤胸径(DBH)<25 cm〕为主,占比达66.1%,属于衰退型种群。从静态生命表看,宝华玉兰种群的生命期望随着径级的增加逐渐下降,种群存活曲线趋向于Deevey-Ⅱ型。生存分析结果显示:宝华玉兰种群趋势具有前期锐减、中期稳定、后期衰退的特点。种群动态量化分析结果表明:宝华玉兰种群动态总体呈增长趋势,但增长极为缓慢。基于上述研究结果,建议采取人工播种、补植实生苗等方式加强对宝华玉兰种群的保护和管理,促进其种群的更新和良性发展。

利用自我重复取样匹配技术组建生命表:以梨小食心虫为例

【目的】针对一些昆虫在进行生命表研究时由于个体从出生到死亡的发育、存活和繁殖数据无法连续记录或难以记录的问题,本研究旨在引入一种适宜该类昆虫的生命表组建技术,并证明该技术的可靠性。【方法】将24个以传统方式组建的昆虫连续记录生命表拆分为未成熟期与成虫期生命表,再利用自我重复取样匹配技术重新组建新的完整生命表,与原始生命表的主要种群参数进行比较与验证。利用该技术重新组建包含滞育期的梨小食心虫Grapholita molesta生命表,并借助模拟软件预测越冬种群增长趋势,将预测的种群数据与田间取样数据进行对比。【结果】24个种群基于0.5百分位净增殖率(R_(0))和周限增长率(λ)采用自我重复取样匹配构建的生命表的种群参数与原始生命表一致。梨小食心虫自我重复取样匹配生命表无滞育期与含180 d滞育期的生命表周限增长率(λ)、内禀增长率(r)与平均世代周期(T)有显著差异,但净增殖率(R_(0))与平均繁殖率(F)无显著差异。进行种群增长预测时,忽略滞育期会高估田间种群的增长潜力,呈现不现实的快速增长,而包含180 d滞育期的同时降低繁殖率并增加越冬期幼虫的死亡率的生命表,可得到更接近田间观察的实际种群结构。【结论】本研究展示了分别独立收集未成熟期和成虫期数据,利用两性生命表软件经100000次自我重复取样和匹配,进而组建完整生命表的技术。借助年龄-龄期两性生命表理论的计算机模拟可以预测害虫种群增长,有助于确定防治的最佳时期和制定有效的害虫管理方案,以促进农业可持续发展。

集合论、笛卡尔乘积和多项式定理在生命表研究中的应用:以取食玉米粒和茶树叶片的棉铃虫生命表为例

【目的】自我重复取样技术(bootstrap technique)广泛用于计算生命表各参数的方差、标准误和置信区间(confidence interval),而配对自我重复取样检验(paired bootstrap test,PBT)则用于检测处理间的生命表参数差异。本研究以取食玉米粒和茶树叶片的棉铃虫Helicoverpa armigera生命表为例,进一步解释集合论、笛卡尔乘积和多项式定理在害虫种群生物学研究中的应用。【方法】利用年龄-龄期两性生命表对取食玉米粒和茶树叶片的棉铃虫种群参数进行分析,利用集合论、笛卡尔乘积和多项式定理将种群统计分析以明确数学的方法呈现,以检测所有可能的自我重复取样样本、精确计算种群参数置信区间以及处理之间差异的置信区间,计算可育和不育样本的概率。【结果】取食茶树叶片的棉铃虫其成虫前期存活率、内禀增长率(r)、周限增长率(λ)、净增殖率(R_(0))、平均世代周期(T)均显著低于取食玉米粒的,说明茶树叶片不是棉铃虫的适宜寄主植物。因取食茶树叶片棉铃虫种群不育样本数较多,利用bootstrap重复取样接受可育与不育样本时,其结果与不用bootstrap技术计算的差异小于5%;若取样时仅接受可育样本,结果与原数值差异显著,误差较大(>5%)。使用笛卡尔配对检验(Cartesian paired test,CPT)比较取食两种食物的棉铃虫种群的R0的差异时,可计算两种处理bootstrap抽样结果所有可能差异的精确置信区间,而使用自我重复取样检验通常会导致置信区间的估值过高或过低,尤其是自我重复取样数较小时。多项式定理可以揭示可育和不育样本的自我重复取样结果。自我重复取样抽样记录必须保留,以便在后续分析中进一步应用。【结论】本研究进一步明确了两性生命表理论的数学基础,也为昆虫学研究中的生命表技术的应用提供数学支撑。

1990-2020年中国的婚姻状况变迁

本文使用1990-2020年全国人口普查数据,应用多增-减婚姻生命表和间接估计法估算了我国人口的婚姻生命表,考察了我国人口的婚姻状况变迁模式。研究发现:(1)我国存在较为明显的婚姻推迟现象;(2)有配偶预期寿命占预期寿命的比重下降;(3)离婚水平有所增加,离婚预期寿命及其占预期寿命的比重不断提升,但整体离婚水平处于较低水平;(4)死亡水平的下降促使我国人口的丧偶预期寿命及其占预期寿命的比重有所降低。总体来看,我国当前仍是婚姻结构比较稳定的普婚型国家,但受婚姻推迟和离婚水平升高等影响,婚姻稳定性在未来可能进一步减弱。此外,女性婚姻状况的变迁趋势比男性更加明显,婚姻推迟和离婚现象更为突出。

25岁以下未育女性负压吸宫术后即时放置两种宫内节育器的随机对照观察

目的:观察25岁以下未育女性负压吸宫术后即时分别放置吉妮致美或含药含铜宫型宫内节育器(IUD)的可行性和效果。方法:将自愿要求人工流产的≤25岁未育早孕女性作为观察对象,随机表法分组,分别放置吉妮致美IUD组(195例)和含药含铜宫型IUD组(简称宫药铜组)(196例)。于负压吸宫术后即时放置IUD,随访6个月,观察IUD的使用效果。结果:两组IUD的顺利放置率≥99%。采用生命表法对IUD的终止情况进行分析。两组均无妊娠发生,宫药铜组无脱落相关终止,吉妮致美组脱落相关终止率为2.09/100妇女年,高于宫药铜组(P<0.05)。吉妮致美组因症取出率为0.53/100妇女年,宫药铜组为1.60/100妇女年,但差异无统计学意义(P>0.05)。吉妮致美组和宫药铜组与IUD使用相关的终止率分别为1.60/100妇女年和2.60/100妇女年,两组间差异无统计学意义(P>0.05)。放置IUD后1、3、6个月随访时,吉妮致美组和宫药铜组IUD副作用的主诉率分别为17.3%、13.4%、6.7%和28.7%、29.5%、21.5%,吉妮致美组低于宫药铜组,差异有统计学意义(P<0.01、P<0.001、P<0.001)。结论:年轻未育女性负压吸宫术后即时放置吉妮致美或宫药铜IUD均安全、可行、避孕效果可靠,与宫药铜IUD相比吉妮致美IUD使用后不适主诉更少,需关注放置技术以减少脱落。

新疆库尔勒八字地老虎在不同温度下的种群生命表及灯下成虫种群动态

【目的】研究温度对新疆库尔勒八字地老虎Xestia c-nigrum生长发育和繁殖的影响,明确其对环境温度的适应能力。【方法】利用两性生命表方法比较15, 20, 25, 30和35℃下八字地老虎卵孵化率、幼虫存活率、化蛹率、羽化率、发育历期及繁殖力,分析不同温度对其种群生命表参数的影响,并计算不同发育阶段的发育起点温度和有效积温。利用灯诱监测数据分析2020-2022年期间新疆库尔勒农区八字地老虎种群动态与日平均温度变化的关系。【结果】15℃时八字地老虎幼虫存活率、化蛹率、羽化率均低于30%,30℃时幼虫存活率、化蛹率低于10%且蛹不能正常羽化,35℃时幼虫不能存活。八字地老虎各发育阶段历期随温度升高而缩短,15, 20, 25, 30和35℃时卵历期分别为15.52, 7.40, 5.47, 4.88和3.88 d;15, 20, 25和30℃时幼虫历期分别为109.43, 40.53, 26.48和24.55 d;15, 20和25℃时蛹历期分别为41.43, 18.00和12.54 d。15℃时种群呈负增长,20和25℃时种群呈正增长,其中25℃时内禀增长率(r_m)最大。八字地老虎卵、1-6龄幼虫和蛹的发育起点温度分别为9.81, 8.43,9.95, 10.26, 12.52, 13.58, 12.60和10.81℃,有效积温依次为79.62, 92.17, 56.09, 57.03, 39.35, 38.16, 80.72和172.39日·度。2020-2022年灯诱监测数据表明,八字地老虎在新疆库尔勒每年发生3代,成虫高峰期分别在5月中旬、7月下旬和9月上旬,对应的日平均温度在19.5~26.5℃之间。【结论】低于15℃时八字地老虎种群呈负增长,超过30℃时不能完成生活史,而20~25℃比较适合八字地老虎的生长与繁殖,该结果为明确新疆库尔勒八字地老虎的温度适应能力及其发生规律提供了科学依据。

7种榕属植物叶片的理化性质及对朱红毛斑蛾生长发育的影响

为探究相较于其余5种榕属植物,朱红毛斑蛾Phauda flammans偏好小叶榕Ficus concinna及垂叶榕F.benjamina的原因。本文通过测量比较7种常用的园林绿化榕属植物营养物质、次生代谢物质以及物理性状,采用室内饲养观察与调查统计的方法评估朱红毛斑蛾在小叶榕和垂叶榕上的发育历期和种群生命表参数。结果发现,与黄葛树、无花果、对叶榕、高山榕和印度榕相比,小叶榕和垂叶榕叶片可溶性糖含量分别为98.47μg/g与65.21μg/g;可溶性蛋白含量分别为4.18 mg/g与0.95 mg/g;含水量分别为0.84%与0.95%;叶片厚度分别为3.59 mm与2.65 mm;硬度分别为3.91 mN与3.49 mN;朱红毛斑蛾仅在小叶榕和垂叶榕上能完成生活史;与垂叶榕相比,取食小叶榕后的幼虫、蛹和成虫的生长发育历期更短,分别为50.25 d、11.48 d和4.28 d,种群存活率和繁殖率更高,且自然死亡排除控制指数为1.68,低于垂叶榕。说明小叶榕和垂叶榕叶片含有较高的营养物质、较低含量的次生代谢物质、较小的叶片硬度,导致朱红毛斑蛾偏好小叶榕和垂叶榕,并能完成生活史。因此在基于榕树植物的园林绿化造景过程中,应注意树种的搭配,降低朱红毛斑蛾对城市园林景观和生态效益的影响。