像鸟儿一样飞行

人类在制造飞机的过程中,一直在试图借鉴鸟的飞行技巧。最先被人类模仿的飞行方式是扑翼飞行,这可能是由于人类最初总是喜欢用最感性的方式去认识世界。但是,扑翼飞行是以鸟类特殊的生理结构为基础的。比如说,鸟类的胸肌非常发达,依靠胸肌的收缩、舒张,带动翅膀上下扇动,能产生足以支持并超过鸟类体重的动力。而人力乃至后来制造的机械在这方面根本就是望尘莫及。     

像鸟儿一样飞行

人类在制造飞机的过程中,一直在试图借鉴鸟的飞行技巧。最先被人类模仿的飞行方式是扑翼飞行,这可能是由于人类最初总是喜欢用最感性的方式去认识世界。但是,扑翼飞行是以鸟类特殊的生理结构为基础的。比如说,鸟类的胸肌非常发达,依靠胸肌的收缩、舒张,带动翅膀上下扇动,能产生足以支持并超过鸟类体重的动力。而人力乃至后来制造的机械在这方面根本就是望尘莫及。     

挥发性化合物对枯叶蛱蝶觅食的引诱作用

【目的】鉴于枯叶蛱蝶Kallima inachus(Boisduval)在觅食过程中以嗅觉信息为主导,本研究试图找出吸引枯叶蛱蝶觅食的关键化合物。【方法】本文利用顶空抽样法收集了西瓜、柿子、香蕉、苹果、橙和梨6种半腐烂水果的挥发物,并用GC/MS测定了其成分。然后从中筛选出5种挥发物以及前人报道的存在于腐烂发酵物中的乙醇和乙酸,通过田间行为观察研究了枯叶蛱蝶对这些挥发物分别与乙醇和去离子水对比的引诱效果。【结果】在0.5%浓度下,供试挥发物都对枯叶蛱蝶觅食有一定的引诱作用,其中,乙酸乙酯、丁酮和α-蒎烯引诱效果与乙醇无显著差异(P>0.05),且均显著高于去离子水(P<0.05);异戊醇、乙酸和乙酸异戊酯的引诱效果均显著低于乙醇(P<0.05),略高于去离子水但均差异不显著(P>0.05);乙醇的引诱次数高于丁酮、α-蒎烯、异戊醇、乙酸和乙酸异戊酯。【结论】乙醇是枯叶蛱蝶觅食的关键化合物;枯叶蛱蝶在觅食过程中可利用多种气味信息。结果可为今后制定枯叶蛱蝶保护措施提供依据。     

栖息地质量对两种网蛱蝶集合种群结构和分布的影响

在河北省赤城县研究了栖息地质量对大网蛱蝶Melitaea phoebe和金堇蛱蝶Euphydryas aurinia两种网蛱蝶集合种群结构和分布的影响。这两种网蛱蝶在约10 km_²的区域内共存,成虫期的蜜源植物几乎相同,大网蛱蝶的发生峰期比金堇蛱蝶晚约一个月,两者只有不到一周左右的时间重叠。大网蛱蝶和金堇蛱蝶幼虫的寄主植物分别是: 祁州漏芦（菊科）和华北蓝盆花（川续断科）。蜜源植物的丰度与两种网蛱蝶的局域种群大小呈正相关;祁州漏芦的密度对大网蛱蝶的局域种群大小影响很大,金堇蛱蝶的局域种群大小则与其寄主植物华北蓝盆花的高度正相关;斑块内平均植被高度与两种网蛱蝶的局域种群大小均呈正相关,植物多样性、植物均匀性和植被盖度均与金堇蛱蝶的局域种群大小负相关,与大网蛱蝶的关系不大。同时分析了其他因子如斑块的坡向、坡度等的影响。主要结论是：1）幼虫寄主植物的不同和成蝶飞行峰期的分离允许两种网蛱蝶在这样一个小的斑块区域内共存;2）蜜源是重要的限制因子,并且受气候随机性的影响很大,蜜源的波动可以很好地解释网蛱蝶集合种群在年度间的动态变化;3）大网蛱蝶和金堇蛱蝶的飞行、食物搜寻能力的不同以及各自寄主植物的生物学特性、空间分布的不同决定了它们具有不同的集合种群结构： 金堇蛱蝶是经典的集合种群,大网蛱蝶是源-汇集合种群;4）斑块质量和昆虫行为共同决定了两种网蛱蝶的集合种群结构和分布。     

昆虫个体大小对其种群生物学的影响

个体大小是昆虫种群最直观的表型之一。很多研究发现,个体大小可对昆虫的许多生物学特性产生影响,由此影响昆虫种群的发展以及所在群落的结构和功能。根据最近20多年的相关文献,综述了个体大小对种群以下几方面的影响:成虫求偶、交配、生殖力及后代适合度,飞行及与飞行相关的其他行为如觅食、空中求偶和交配,摄食能力和食料种类,竞争和防御能力,抗逆性,以及社会性昆虫的劳动分工等。通常情况下,与同种内较小个体相比,较大的昆虫在生殖、飞行、抗逆性等方面往往具有优势,有助于种群适合度的提高。最后提出了几点可供此领域研究参考的建议和应用启示。     

普通长翼蝠食性结构及其回声定位与体型特征

在普通长翼蝠(Miniopterus fuliginosus)的捕食区内用灯诱法和网捕法调查潜在食物(昆虫)种类; 用粪便分析法鉴定普通长翼蝠的食物组成,发现其主要捕食体型较大的鳞翅目和鞘翅目昆虫,体积百分比分别为55%和38%.普通长翼蝠具有相对狭长的翼,翼展比为6.94 ± 0.13;翼载为(9.85 ± 0.83)N/m2,相对较大.飞行状态下普通长翼蝠的回声定位叫声为调频下扫型,声脉冲时程为(1.45 ± 0.06)ms,脉冲间隔为(63.08 ± 21.55)ms,主频较低,为(44.50 ± 2.26)kHz.研究表明,普通长翼蝠的形态特征和回声定位特征与其捕食行为有着密切的联系.     

昆虫趋光的性别差异及其影响因素

趋光是众多夜行性昆虫的主要行为特征之一.研究表明: 许多夜行性昆虫的趋光存在明显的性别差异现象,而这种差异受多种因素的影响.本文从雌雄成虫飞行能力差异导致其飞行距离与高度的不同、雌雄成虫复眼结构差异导致其对光源反应不同,以及雌雄成虫对光源和环境刺激的敏感性不同等方面综述了导致昆虫趋光性别差异的因素,并探讨了昆虫趋光性别差异的应用及今后研究方向.     

微生物对昆虫行为的影响研究进展

在漫长的进化过程中,微生物与昆虫形成了多种形式的互作关系。微生物的广泛分布为与昆虫接触并影响昆虫的行为提供了背景条件。为了深入探究微生物影响昆虫行为的现象和机制,本文综述了微生物影响昆虫行为方面的研究进展。微生物通过产生可被昆虫识别的化学信号物质、参与昆虫或寄主植物信息化合物的合成等方式可影响昆虫对其寄主的定位和选择。在对昆虫种内和种间关系的研究中也发现微生物起着非常重要的作用。通过改变昆虫性信息素等方式,微生物还能影响到昆虫的繁殖行为;除此之外,微生物合成或参与合成的信息化合物还可以影响昆虫的社会性和聚集等行为。根据当前对微生物影响昆虫行为方面的研究现状,我们建议可进一步研究：(1)微生物影响昆虫行为的过程中,影响昆虫行为的信息化合物是如何产生的？(2)微生物在影响昆虫行为的过程中是否涉及更多的物种间互作？(3)对于一些在特定时期可影响昆虫行为的共生微生物来说,宿主昆虫是如何获得并维持这些微生物的？     

跟着昆虫去飞行

早在3亿年前,昆虫已经翱翔在辽阔的天空,成为最早在空中飞行的动物,并且在今天仍然延续着它们的飞行史。经过了漫长且充满变数的进化,昆虫获得了令人惊叹的飞行技巧,如飞行速度快、距离长、耗能少、灵活性强等,尤其它们高度的飞行灵活性是任何现有的飞行器都无法比拟的。     

跟着昆虫去飞行

早在3亿年前,昆虫已经翱翔在辽阔的天空,成为最早在空中飞行的动物,并且在今天仍然延续着它们的飞行史。经过了漫长且充满变数的进化,昆虫获得了令人惊叹的飞行技巧,如飞行速度快、距离长、耗能少、灵活性强等,尤其它们高度的飞行灵活性是任何现有的飞行器都无法比拟的。     

Flight mechanics of a tailless articulated wing aircraft

This paper investigates the flight mechanics of a micro aerial vehicle without a vertical tail in an effort to reverse-engineer the agility of avian flight. The key to stability and control of such a tailless aircraft lies in the ability to control the incidence angles and dihedral angles of both wings independently. The dihedral angles can be varied symmetrically on both wings to control aircraft speed independently of the angle of attack and flight path angle, while asymmetric dihedral can be used to control yaw in the absence of a vertical stabilizer. It is shown that wing dihedral angles alone can effectively regulate sideslip during rapid turns and generate a wide range of equilibrium turn rates while maintaining a constant flight speed and regulating sideslip. Numerical continuation and bifurcation analysis are used to compute trim states and assess their stability. This paper lays the foundation for design and stability analysis of a flapping wing aircraft that can switch rapidly from flapping to gliding flight for agile manoeuvring in a constrained environment.     

Aerial locomotion in flies and robots: kinematic control and aerodynamics of oscillating wings

Flight in flies results from a feedback cascade in which the animal converts mechanical power produced by the flight musculature into aerodynamic forces. A major goal of flight research is to understand the functional significance of the various components in this cascade ranging from the generation of the neural code, the control of muscle mechanical power output, wing kinematics and unsteady aerodynamic mechanisms. Here, I attempted to draw a broad outline on fluid dynamic mechanisms found in flapping insect wings such as leading edge vorticity, rotational circulation and wake capture momentum transfer, as well as on the constraints of flight force control by the neuromuscular system of the fruit fly Drosophila. This system-level perspective on muscle control and aerodynamic mechanisms is thought to be a fundamental bridge in any attempt to link the function and performance of the various flight components with their particular role for wing motion and aerodynamic control in the behaving animal. Eventually, this research might facilitate the development of man-made biomimetic autonomous micro air vehicles using flapping wing motion for propulsion that are currently under construction by engineers.     

A wing-assisted running robot and implications for avian flight evolution

DASH+Wings is a small hexapedal winged robot that uses flapping wings to increase its locomotion capabilities. To examine the effects of flapping wings, multiple experimental controls for the same locomotor platform are provided by wing removal, by the use of inertially similar lateral spars, and by passive rather than actively flapping wings. We used accelerometers and high-speed cameras to measure the performance of this hybrid robot in both horizontal running and while ascending inclines. To examine consequences of wing flapping for aerial performance, we measured lift and drag forces on the robot at constant airspeeds and body orientations in a wind tunnel; we also determined equilibrium glide performance in free flight. The addition of flapping wings increased the maximum horizontal running speed from 0.68 to 1.29 m s?1, and also increased the maximum incline angle of ascent from 5.6° to 16.9°. Free flight measurements show a decrease of 10.3° in equilibrium glide slope between the flapping and gliding robot. In air, flapping improved the mean lift:drag ratio of the robot compared to gliding at all measured body orientations and airspeeds. Low-amplitude wing flapping thus provides advantages in both cursorial and aerial locomotion. We note that current support for the diverse theories of avian flight origins derive from limited fossil evidence, the adult behavior of extant flying birds, and developmental stages of already volant taxa. By contrast, addition of wings to a cursorial robot allows direct evaluation of the consequences of wing flapping for locomotor performance in both running and flying.     

Morphology, Velocity, and Intermittent Flight in Birds

Body size, pectoralis composition, aspect ratio of the wing,and forward speed affect the use of intermittent flight in birds.During intermittent non-flapping phases, birds extend theirwings and glide or flex their wings and bound. The pectoralismuscle is active during glides but not during bounds; activityin other primary flight muscles is variable. Mechanical power,altitude, and velocity vary among wingbeats in flapping phases;associated with this variation are changes in neuromuscularrecruitment, wingbeat frequency, amplitude, and gait. Speciesof intermediate body mass (35–158 g) tend to flap-glideat slower speeds and flap-bound at faster speeds, regardlessof the aspect ratio of their wings. Such behavior may reducemechanical power output relative to continuous flapping. Smallerspecies (<20 g) with wings of low aspect ratio may flap-boundat all speeds, yet existing models do not predict an aerodynamicadvantage for the flight style at slow speeds. The behaviorof these species appears to be due to wing shape rather thanpectoralis physiology. As body size increases among species,percent time spent flapping increases, and birds much largerthan 300 g do not flap-bound. This pattern may be explainedby adverse scaling of mass-specific power or lift per unit poweroutput available from flight muscles. The size limit for theability to bound intermittently may be offset somewhat by thescaling of pectoralis composition. The percentage of time spentflapping during intermittent flight also varies according toflight speed.     

Modulation of leading edge vorticity and aerodynamic forces in flexible flapping wings

In diverse biological flight systems, the leading edge vortex has been implicated as a flow feature of key importance in the generation of flight forces. Unlike fixed wings, flapping wings can translate at higher angles of attack without stalling because their leading edge vorticity is more stable than the corresponding fixed wing case. Hence, the leading edge vorticity has often been suggested as the primary determinant of the high forces generated by flapping wings. To test this hypothesis, it is necessary to modulate the size and strength of the leading edge vorticity independently of the gross kinematics while simultaneously monitoring the forces generated by the wing. In a recent study, we observed that forces generated by wings with flexible trailing margins showed a direct dependence on the flexural stiffness of the wing. Based on that study, we hypothesized that trailing edge flexion directly influences leading edge vorticity, and thereby the magnitude of aerodynamic forces on the flexible flapping wings. To test this hypothesis, we visualized the flows on wings of varying flexural stiffness using a custom 2D digital particle image velocimetry system, while simultaneously monitoring the magnitude of the aerodynamic forces. Our data show that as flexion decreases, the magnitude of the leading edge vorticity increases and enhances aerodynamic forces, thus confirming that the leading edge vortex is indeed a key feature for aerodynamic force generation in flapping flight. The data shown here thus support the hypothesis that camber influences instantaneous aerodynamic forces through modulation of the leading edge vorticity.     

Physical theory,origin of flight,and a synthesis proposed for birds

Neither flapping and running to take-off nor gliding from heights can be disproved as the assured evolutionary origin of self-powered flight observed in modern vertebrates. Gliding with set wings would utilize available potential energy from gravity but gain little from flapping. Bipedal running, important in avian phylogeny, possibly facilitated the evolution of flight. Based on physical principles, gliding is a better process for the origin of powered flight than the "ground-up" process, which physically is not feasible in space or time (considering air resistance, metabolic energy costs, and mechanical resistance to bipedal running). Proto-avian ancestors of Archaeopteryx and Microraptor probably flapped their sparsely feathered limbs synchronously while descending from leaps or heights, with such "flutter-gliding" presented as a synthesis of the two earlier theories of flight origin (making use of the available potential energy from gravity, involving wing thrusts and flapping, coping with air resistance that slows air speed, but effecting positive fitness value in providing lift and slowing dangerous falls).     

Design and Demonstration of Insect Mimicking Foldable Artificial Wing Using Four-Bar Linkage Systems

In this work, we develop an artificial foldable wing that mimics the hind wing of a beetle （Allomyrina dichotoma）. In real flight, the beetle unfolds forewings and hind wings, and maintains the unfolded configuration unless it is exhausted. The artificial wing has to be able to maintain a fully unfolded configuration while flapping at a desirable flapping frequency. The artificial foldable hind wing developed in this work is based on two four-bar linkages which adapt the behaviors of the beetle＇s hind wing. The four-bar-linkages are designed to mimic rotational motion of the wing base and the vein folding/unfolding motion of the beetle＇s hind wing. The behavior of the artificial wings, which are installed in a flapping-wing system, is observed using a high-speed camera. The observation shows that the wing could maintain a fully unfolded configuration during flapping motion. A series of thrust measurements are also conducted to estimate the force generated by the flapping-wing system with foldable artificial wings. Although the artificial foldable wings give added burden to the flapping-wing system because of its weight, the thrust measurement results show that the flapping-wing system could still generate reasonable thrust.     

Coordination of wingbeat and respiration in the Canada goose. I. Passive wing flapping.

The effects of passive wing flapping on respiratory pattern were examined in decerebrate Canada geese. The birds were suspended dorsally with two spine clamps while the extended wings were continuously moved up and down with a device designed to reproduce actual wing flapping. Passive wing motion entrained respiration over limited ranges by both increasing and decreasing the respiratory period relative to rest. All ratios of wingbeat frequency to respiratory frequency seen during free flight (Soc. Neurosci. Abstr. 15: 391, 1989) were produced during passive wing flapping. In addition, the phase relationship between wingbeat frequency and respiratory frequency, inspiration starting near the peak of wing upstroke, was similar to that seen during free flight and was unaffected by perturbations of the wing-flapping cycle. Removal of all afferent activity from the wings did not affect the ability of continuous passive wing movement to entrain respiration. However, feedback from the wings was required to produce rapid within-breath shifts in the respiratory period in response to single wing flaps. In conclusion, although feedback from the chest wall/lung may be more important in producing entrainment during the stable conditions of passive wing flapping, wing-related feedback may be critically involved in mediating the rapid adjustments in respiratory pattern required to maintain coordination between wing and respiratory movements during free flight.     

Animal flight dynamics II. Longitudinal stability in flapping flight

Stability is essential to flying and is usually assumed to be especially problematic in flapping flight. If so, problems of stability may have presented a particular hurdle to the evolution of flapping flight. In spite of this, the stability of flapping flight has never been properly analysed. Here we use quasi-static and blade element approaches to analyse the stability provided by a flapping wing. By using reduced order approximations to the natural modes of motion, we show that wing beat frequencies are generally high enough compared to the natural frequencies of motion for a quasi-static approach to be valid as a first approximation. Contrary to expectations, we find that there is noting inherently destabilizing about flapping: beating the wings faster simply amplifies any existing stability or instability, and flapping can even enhance stability compared to gliding at the same air speed. This suggests that aerodynamic stability may not have been a particular hurdle in the evolution of flapping flight. Hovering animals, like hovering helicopters, are predicted to possess neutral static stability. Flapping animals, like fixed wing aircraft, are predicted to be stable in forward flight if the mean flight force acts above and/or behind the centre of gravity. In this case, the downstroke will always be stabilizing. The stabilizing contribution may be diminished by an active upstroke with a low advance ratio and more horizontal stroke plane; other forms of the upstroke may make a small positive contribution to stability. An active upstroke could, therefore, be used to lower stability and enhance manoeuvrability. Translatory mechanisms of unsteady lift production are predicted to amplify the stability predicted by a quasi-static analysis. Non-translatory mechanisms will make little or no contribution to stability. This may be one reason why flies, and other animals which rely upon non-translatory aerodynamic mechanisms, often appear inherently unstable.     

Kinematic compensation for wing loss in flying damselflies

Flying insects can tolerate substantial wing wear before their ability to fly is entirely compromised. In order to keep flying with damaged wings, the entire flight apparatus needs to adjust its action to compensate for the reduced aerodynamic force and to balance the asymmetries in area and shape of the damaged wings. While several studies have shown that damaged wings change their flapping kinematics in response to partial loss of wing area, it is unclear how, in insects with four separate wings, the remaining three wings compensate for the loss of a fourth wing. We used high-speed video of flying blue-tailed damselflies (Ischnura elegans) to identify the wingbeat kinematics of the two wing pairs and compared it to the flapping kinematics after one of the hindwings was artificially removed. The insects remained capable of flying and precise maneuvering using only three wings. To compensate for the reduction in lift, they increased flapping frequency by 18 ± 15.4% on average. To achieve steady straight flight, the remaining intact hindwing reduced its flapping amplitude while the forewings changed their stroke plane angle so that the forewing of the manipulated side flapped at a shallower stroke plane angle. In addition, the angular position of the stroke reversal points became asymmetrical. When the wingbeat amplitude and frequency of the three wings were used as input in a simple aerodynamic model, the estimation of total aerodynamic force was not significantly different (paired t-test, p = 0.73) from the force produced by the four wings during normal flight. Thus, the removal of one wing resulted in adjustments of the motions of the remaining three wings, exemplifying the precision and plasticity of coordination between the operational wings. Such coordination is vital for precise maneuvering during normal flight but it also provides the means to maintain flight when some of the wings are severely damaged.