Dynamic flight stability of hovering model insects:theory versus simulation using equations of motion coupled with Navier-Stokes equations

In the present paper, the longitudinal dynamic flight stability properties of two model insects are predicted by an approximate theory and computed by numerical sim- ulation. The theory is based on the averaged model （which assumes that the frequency of wingbeat is sufficiently higher than that of the body motion, so that the flapping wings＇ degrees of freedom relative to the body can be dropped and the wings can be replaced by wingbeat-cycle-average forces and moments）; the simulation solves the complete equations of motion coupled with the Navier-Stokes equations. Comparison between the theory and the simulation provides a test to the validity of the assumptions in the theory. One of the insects is a model dronefly which has relatively high wingbeat frequency （164 Hz） and the other is a model hawkmoth which has relatively low wingbeat frequency （26 Hz）. The results show that the averaged model is valid for the hawkmoth as well as for the dronefly. Since the wingbeat frequency of the hawkmoth is relatively low （the characteristic times of the natural modes of motion of the body divided by wingbeat period are relatively large） compared with many other insects, that the theory based on the averaged model is valid for the hawkmoth means that it could be valid for many insects.

Nanoindentation Mechanical Properties and Structural Biomimetic Models of Three Species of Insects Wings

Mimicking insect flights were used to design and develop new engineering materials. Although extensive research was done to study various aspects of flying insects. Because the detailed mechanics and underlying principles involved in insect flights remain largely unknown. A systematic study was carried on insect flights by using a combination of several advanced techniques to develop new models for the simulation and analysis of the wing membrane and veins of three types of insect wings, namely dragonfly （Pantala flavescens Fabricius）, honeybee （Apis cerana cerana Fabricius） and fly （Sarcophaga carnaria Linnaeus）. In order to gain insights into the flight mechanics of insects, reverse engineering methods were used to establish three-dimensional geometrical models of the membranous wings, so we can make a comparative analysis. Then nano-mechanical test of the three insect wing membranes was performed to provide experimental parameter values for mechanical models in terms of nano-hardness and elastic modulus. Finally, a computational model was established by using the finite element analysis （ANSYS） to analyze and compare the wings under a variety of simplified load regimes that are concentrated force, uniform line-load and a torque. This work opened up the possibility towards developing an engineering basis for the biomimetic design of thin solid films and 2D advanced engineering composite materials.

Enhancement of density divergence in an insect outbreak model driven by colored noise

The steady states and the transient properties of an insect outbreak model driven by Gaussian colored noise are studied in this paper. According to the Fokker-Planck equation in the unified colored-noise approximation, we analyse the stationary probability distribution and the mean first-passage time of this model. By numerical analysis, the effects of the self-correlation time of insect birth rate and predation rate respectively reveal a manifest population divergence on the insect density. The decrease of the mean first-passage time indicates an enhancement dynamic on the density divergency with colored noise of a large self-correlation time based on the insect outbreak model.

Added Mass Effect and an Extended Unsteady Blade Element Model of Insect Hovering

During the insect flight, the force peak at the start of each stroke contributes a lot to the total aerodynamic force. Yet how this force is generated is still controversial. Two current explanations to this are wake capture and Added Mass Effect （AME） mechanisms. To study the AME, we present an extended unsteady blade element model which takes both the added mass of fluid and rotational effect of the wing into account. Simulation results show a high force peak at the start of each stroke and are quite similar to the measured forces on the physical wing model. We found that although the Added Mass Force （AMF） of the medium contributes a lot to this force peak, the wake capture effect further augments this force and may play a more important role in delayed mode. Furthermore, we also found that there might be an unknown mechanism which may augment the AME during acceleration period at the start of each stroke, and diminish the AME during deceleration at the end of each stroke.

Extinction Conditions from a One-Sided Competition Model with a Holling Type I Functional Response for the Sterile Insect Technique

The Sterile Insect Technique (SIT) is a powerful biological tool to control pest-populations. It could be integrated in management programmes of the Red Palm Weevil (RPW) Rhynchophorus ferrugineus Olivier. This pest threatens seriously date palms particularly in Saudi Arabia. As a matter of fact, the use of SIT has been very efficient in controlling RPW populations in coconut gardens in various countries. In this work, we outline the extinction conditions of a target wild-population using a one-sided competition model to describe its competition with released sterile insects. We employ a Holling type I functional response to describe the sterile-fertile one-sided competition and we consider two intra-specific competition sub-models, with and without Allee Effect, in modelling the growth of the wild-type population. We also study two manners of liberating sterile insects: single and periodic release strategies.

Finding Food Security through Changing the Agricultural Model to Sustain Insect Biodiversity

Worldwide biodiversity is being threatened by human activities to a greater level wherein the natural ecosystems are reaching the verge of collapsing. We are faced with four major interrelated challenges namely a changing climate, biodiversity loss, human population growth and food production for this growing population. Agricultural intensification contributes significantly to biodiversity loss. The agricultural model for our current food production systems is mainly based on the Green Revolution, which promoted the cultivation of crops in extensive monoculture fields and intensified external inputs of agrochemicals. This model resulted in biodiversity loss, particularly in insect populations. A model based on ecological intensification as an alternative to agricultural intensification with minimized use of agro-inputs may slow the rate of biodiversity loss resulting in more sustainable agricultural ecosystems.

基于卷积神经网络的入侵昆虫识别研究

现有昆虫相关识别算法识别种类较少,缺少针对数量庞大种类众多的入侵昆虫分类识别算法,难以为入侵昆虫综合系统的识别功能提供稳定高效的技术支持。该研究对31类入侵昆虫图像进行数据采集,并对图像数据进行处理与数据集划分,基于四种卷积神经网络模型DenseNet121、MobileNetV3、ResNet101和ShuffleNet对其进行训练测试分析讨论。结果表明,在入侵昆虫综合识别系统识别功能后台算法应用上,MobileNetV3表现出更好的综合性能。根据MobileNetV3模型现有缺陷和模型特性,对MobileNetV3模型指定瓶颈层的注意力机制和激活函数进行改进,改进后模型的准确率为92.8%,单张测试集图像的平均识别时间0.012 s,相较于原MobileNetV3模型分别提高0.5%、缩短15.2%,可以很好满足多昆虫识别分类需求。

菜粉蝶及其近缘种东方菜粉蝶全球潜在分布区预测

重要农业害虫菜粉蝶(Pieris rapae)及其近缘种东方菜粉蝶(Pieris canidia)幼虫主要危害十字花科的多种蔬菜和油料作物,对农业粮食安全造成重大威胁。收集到菜粉蝶和东方菜粉蝶分布数据共计248393个,其中野外调查收集361个。基于上述现存分布点,利用6种物种分布模型算法对历史、当代和未来气候条件下两种粉蝶在全球的潜在分布区进行了预测。结果表明:(1)基于去除空间自相关后的6个气候变量构建的13种算法的模型预测结果中,有6种算法的模型评估指标的值高于随机状态(0.5)。(2)当代气候条件下,菜粉蝶的潜在分布区主要包括北美洲、南美洲南部、欧洲西部、中国东南部以及澳大利亚南部;东方菜粉蝶主要分布于南美洲北部和亚洲南部等地区。相比于东方菜粉蝶,菜粉蝶在3个时期的潜在分布区面积都要更大,但是东方菜粉蝶在未来气候条件下潜在分布区增加的面积将会更大,具有更高的潜在入侵概率。(3)相比于作为入侵生物的菜粉蝶,其近缘种东方菜粉蝶更能适应高温多雨的气候,面对未来全球变暖的趋势,东方菜粉蝶很有可能成为入侵物种,有必要对其未来气候条件下的潜在分布区,加强虫害监测和防控预报。研究对重要农业害虫菜粉蝶和东方菜粉蝶在不同气候条件下的潜在分布区进行预测和比较,为其防治提供理论依据。

模拟复眼视叶神经网的目标运动方向检测模型

如何对杂乱背景中物体(目标)的运动方向做出准确可靠的检测与感知,是计算机视觉研究领域中一个重要问题。自然界中,飞虫(如苍蝇、蜻蜓等)高适应性和高可靠性的感知目标运动是一种自然特性,本文基于飞虫−果蝇视叶神经纤维网最新的生理学研究成果,提出一种基于果蝇视觉感知目标运动方向的多层级检测模型系统。通过对不同场景下拍摄的视频序列样本进行实验和测试,并与2-Q运动检测器模型、基于ON和OFF信号通道处理运动信息的检测模型等进行了对比,验证了其在杂乱背景下对于目标水平和垂直方向运动检测的有效性和鲁棒性。

Lateral dynamic flight stability of hovering insects: theory vs. numerical simulation

In the present paper, the lateral dynamic flight stability properties of two hovering model insects are predicted by an approximate theory based on the averaged model, and computed by numerical simulation that solves the complete equations of motion coupled with the Naviertokes equations. Comparison between the theoretical and simulational results provides a test to the validity of the assumptions made in the theory. One of the insects is a model dronefly which has relatively high wingbeat frequency （164Hz） and the other is a model hawkmoth which has relatively low wingbeat frequency （26 Hz）. The following conclusion has been drawn. The theory based on the averaged model works well for the lateral motion of the dronefly. For the hawkmoth, relatively large quantitative differences exist between theory and simulation. This is because the lateral non-dimensional eigenvalues of the hawkmoth are not very small compared with the non-dimensional flapping frequency （the largest lateral non-dimensional eigenvalue is only about 10% smaller than the non-dimensional flapping frequency）. Nevertheless, the theory can still correctly predict variational trends of the dynamic properties of the hawkmoth＇s lateral motion.

昆虫脂肪体结构功能及其在人类疾病模型应用中的研究进展

昆虫脂肪体大量分布在昆虫的体内,其是一个动态疏松的组织,包括外周脂肪体和围脏脂肪体两种类型。昆虫脂肪体的结构与功能是息息相关的,其结构会随着昆虫不同生命阶段的变化而变化,其功能也随之发生改变。昆虫脂肪体最基本的功能是作为昆虫生命代谢的核心组织进行物质的合成与储存。此外,脂肪体还有许多重要的功能,是多种激素作用的靶器官,与昆虫的先天免疫、寿命和生长发育等都有关。因此,研究昆虫脂肪体对于解析昆虫重要生命现象是十分重要的。近年来已经有大量研究将昆虫脂肪体作为人类疾病和药物开发等方面的研究模型,将其应用于人类免疫学、人类疾病发病机制探究、新型药物研发等诸多领域。本文对昆虫脂肪体的形态结构、形成与变态、生物学功能及在人类疾病模型研究中的应用与展望进行了综述,以系统地加深对昆虫脂肪体结构与功能的理解与认识。昆虫脂肪体将在人类主要疾病模型的构建、疾病发病机理的探究等方面具有较大的应用潜力。

Modelling the population fluctuation of winter moth and mottled umber moth in central and northern Germany

Background: Winter moth(Operophtera brumata) and mottled umber moth(Erannis defoliaria) are forest Lepidoptera species characterized by periodic high abundance in a 7–11 year cycle. During outbreak years they cause severe defoliation in many forest stands in Europe. In order to better understand the spatio-temporal dynamics and elucidate possible influences of weather, stand and site conditions, a generalized additive mixed model was developed. The investigated data base was derived from glue band catch monitoring stands of both species in Central and North Germany. From the glue bands only female moth individuals are counted and a hazard code is calculated. The model can be employed to predict the exceedance of a warning threshold of this hazard code which indicates a potential severe defoliation of oak stands by winter moth and mottled umber in the coming spring.Results: The developed model accounts for specific temporal structured effects for three large ecoregions and random effects at stand level. During variable selection the negative model effect of pest control and the positive model effects of mean daily minimum temperature in adult stage and precipitation in early pupal stage were identified.Conclusion: The developed model can be used for short-term predictions of potential defoliation risk in Central and North Germany. These predictions are sensitive to weather conditions and the population dynamics. However, a future extension of the data base comprising further outbreak years would allow for deeper investigation of the temporal and regional patterns of the cyclic dynamics and their causal influences on abundance of winter moth and mottled umber.

Development of a New High-throughput Screening Model for Human High Density Lipoprotein Receptor (CLA-1) Agonists

To develop a new high-throughput screening model for human high-density lipoprotein （HDL） receptor （CD36 and LIMPⅡ analogous-1, CLA-1） agonists using CLA-1-expressing insect cells. Methods With the total RNA of human hepatoma cells BEL-7402 as template, the complementary DNA （cDNA） of CLA-1 was amplified by reverse transcription-polymerase chain reaction （RT-PCR）. Bac-to-Bac baculovirus expression system was used to express CLA-1 in insect cells. CLA-1 cDNA was cloned downstream of polyhedrin promoter of Autographa californica nuclear polyhedrosis virus （AcNPV） into donor vector pFastBacl and recombinant pFastBacl-CLA-1 was transformed into E. coli DH10Bac to transpose CLA-1 cDNA to bacrnid DNA. Recombinant bacrnid-CLA-1 was transfected into Spodopterafrugiperda Sf9 insect cells to produce recombinant baculovirus particles. Recombinant CLA- 1 was expressed on the membrane of Sf9 cells infected with the recombinant baculoviruses. A series of parameters of DiI-lipoprotein binding assays of CLA-1-expressing Sf9 cells in 96-well plates were optimized. Results Western blot analysis and DiI-lipoprotein binding assays confirmed that CLA-1 expressed in insect cells had similar immunoreactivity and ligand binding activity as its native counterpart. A reliable and sensitive in vitro cell-based assay was established to assess the activity of CLA-1 and used to screen agonists from different sample libraries. Conclusion Human HDL receptor CLA-1 was successfully expressed in Sf9 insect cells and a novel high-throughput screening model for CLA-1 agonists was developed. Utilization of this model allows us to identify potent and selective CLA-1 agonists which might possibly be used as therapeutics for atherosclerosis.

家蚕细胞色素P450基因的研究进展

细胞色素P450(P450s,CYPs)超基因家族是由数量众多、功能复杂的一类血红蛋白酶基因所组成,对许多结构多样的外源与内源化合物起着氧化代谢的作用。本文系统地综述了家蚕Bombyx mori基因组中P450s的数量与种类,其数量比食腐昆虫和杂食性的植食昆虫少,但比意大利蜜蜂Apis mellifera多,在基因组中大多呈串联重复排列,基因结构与系统进化树之间有着紧密的联系。家蚕与黑腹果蝇Drosophila melanogaster P450s的比较基因组学分析发现,存在10对直向同源基因,但CYP3与CYP4集团(Clan)的P450s表现出种属特异性扩增。家蚕P450s与其蜕皮激素和保幼激素合成代谢有关,并涉及到对氟化物与杀虫剂抗性。家蚕作为鳞翅目昆虫的代表,通过对其P450s的研究,可望为其他昆虫,特别是鳞翅目昆虫的生长发育研究和抗性治理提供理论依据和研究模式。

蛋白质组学技术的发展及其在昆虫中的应用

蛋白质组学在模式昆虫中的应用随着这些模式昆虫全基因序列先后完成而相继展开。蛋白组学作为一门有效而直观的研究整体蛋白质的方法,在非模式昆虫中应用也非常广泛。蛋白质组学在模式昆虫中主要应用于黑腹果蝇Drosophila melanogaster、家蚕Bombyx mori、冈比亚按蚊Anopheles gambiae、意大利蜜蜂Apis mellifera中;在非模式昆虫中主要应用在各种昆虫的生理、药剂毒理和化学生态学研究中。

白蜡虫同地产虫产蜡生产模式构建与分析

白蜡是一种由白蜡虫2龄雄若虫分泌的天然化工原料。传统白蜡生产采用"高山产虫、低山产蜡"的异地生产模式。本研究在白蜡虫生物学、生态学特征基础上构建白蜡虫同地产虫产蜡生产新模式。白蜡虫具有雌虫先孵化,雄虫后孵化特征,卵从10℃以上开始孵化。在15～20℃条件下,若虫16～20天孵化完毕,雌虫孵化高峰期在第9～11天,雄虫孵化高峰期在第14～15天;在25℃条件下,若虫约12天孵化完毕,雌虫孵化高峰期在第4～5天,雄虫孵化高峰期在第10～11天;在30℃条件下,若虫约10天孵化完毕,雌虫孵化高峰期在第3～5天,雄虫孵化高峰期在第6～8天。根据不同温度下白蜡虫孵化速率,建立雌虫孵化的回归方程为:D=12.5-0.35T。在自然状态下,根据白蜡虫孵化率与有效积温的关系建立回归方程:Ha(♀)=(33.767+0.465K)%。在同地产虫产蜡生产模式中,雌虫和雄虫分别放养在产虫区和产蜡区。根据雌虫先孵化、雄虫后孵化特征,将种虫在产虫区放养10,15和18天后转移到产蜡区。放养10天后转移,产虫区雌虫占65%左右,雄虫占15%左右;放养15～18天后转移,产虫区雌虫占70%～80%,雄虫占65%～75%。在同地产虫产蜡生产模式中,培育种虫产量与传统产虫区相同;产蜡量低于传统产蜡区,约为传统产蜡区70%左右,可以通过合理密植寄主植物和选择阴湿环境提高白蜡产量。分析和讨论高山产虫不产蜡、低山产蜡不产虫的原因。

LARGE AERODYNAMIC FORCES ON A SWEEPING WING AT LOW REYNOLDS NUMBER

The aerodynamic forces and flow structure of a model insect wing is studied by solving the Navier-Stokes equations numerically.After an initial start from rest,the wing is made to execute an azimuthal rotation(sweeping)at a large angle of attack and constant angular velocity.The Reynolds number(Re)considered in the present note is 480(Re is based on the mean chord length of the wing and the speed at 60% wing length from the wing root).During the constant-speed sweeping motion,the stall is absent and large and approximately constant lift and drag coefficients can be maintained.The mechanism for the absence of the stall or the maintenance of large aerodynamic force coefficients is as follows.Soon after the initial start,a vortex ring,which consists of the leading-edge vortex(LEV),the starting vortex,and the two wing-tip vortices,is formed in the wake of the wing.During the subsequent motion of the wing,a base-to-tip spanwise flow converts the vorticity in the LEV to the wing tip and the LEV keeps an approximately constant strength.This prevents the LEV from shedding.As a result, the size of the vortex ring increases approximately linearly with time,resulting in an approximately constant time rate of the first moment of vorticity,or approximately constant lift and drag coefficients. The variation of the relative velocity along the wing span causes a pressure gradient along the wing- span.The base-to-tip spanwise flow is mainly maintained by the pressure-gradient force.

物候模型研究进展

近年来随着全球气候变暖,物候提前,物候学的研究越来越受到人们的关注。通过建立物候模型使物候期的预知成为可能,从而为生产实践活动提供依据和指导。本文探讨了物候模型研究的意义,总结了影响植物和昆虫物候的温度、水分、光和养分等主要环境因子的作用。根据国内外物候模型的研究现状,重点介绍了作物、树木、植被和昆虫4类物候模型的研究内容和进展。作物物候模型注重生理生态过程;树木物候模型以统计方法为主,但近期也有尝试将激素水平作为物候的决定因素;植被物候模型以遥感技术的应用为发展趋势;昆虫物候模型则进一步对发育起点的确定和对温度因子的修正,GIS的引入将昆虫物候模型的应用范围扩大。最后指出了目前物候模型研究中存在的问题。

蜜蜂——新兴的模式生物

蜜蜂作为具有重要经济价值和生态价值的社会性昆虫,在诸如神经生物学和社会生物学等研究领域也具有很高的模型价值。蜜蜂基因组工程为深入认识蜜蜂的生物学特点,进一步发挥其在多个研究领域的模型价值奠定了分子基础。本文基于蜜蜂的生物学特点,介绍了蜜蜂作为模式生物所具备的优势,及其在学习和记忆、劳动分工、级型分化、免疫等热点领域的研究价值。通过总结和展望国内外蜜蜂生物学研究形势,呼吁国内相关各学科开展台作研究。

昆虫杆状病毒流行病模拟模型及Java模拟软件(英文)

研究昆虫杆状病毒流行病模拟模型,对确定基因工程改造杆状病毒的主攻方向,明确病毒病田间流行的机制与关键因素,以及制定生物防治策略,均具有重要的理论与实践意义。本研究研制了用于昆虫杆状病毒流行病模拟的数学模型和Java模拟软件,该模型包括描述种群动态的一个微分方程组,描述气温变化、作物生长及病毒动态的若干模型等。模拟软件用工具包JDK和JavaScript开发,由主计算类、图形类、结果显示类、参数输入界面类、警告信息类、主页、用户指南页、版权页、计数页等组成。在参数文件中编入有关作物、病毒、害虫等方面的参数,输入初始的各龄健康、染病虫量、叶面积、病毒密度等,运行后可输出各龄健康、染病及病死的虫量,作物损失,病毒积累等动态,以及图形等等。该模型适用于各种杆状病毒,各种有叶作物,各种食叶性的全变态昆虫。应用该模拟模型,对温度、病毒施用虫龄、病毒施用时间、病毒施用剂量等进行了灵敏度分析,得到了一些重要结论。