昆虫迁飞行为的参数化Ⅰ.行为分析

通过对雷达昆虫学研究和其他方法得到的研究成果的综合分析,提出一套昆虫迁飞行为参数化方案。即：起飞时间以日出日没及晨昏朦影时刻为基准,降落时间依目标昆虫的迁飞特性具体取值;运行高度取边界层顶与目标昆虫飞行低温阈限所在高度之间的气流层,运行方向取风向值并以目标昆虫的定向加以修饰,运行速度为风速与目标昆虫自身飞行速度的矢量和。这套方案可作为昆虫迁飞轨迹数值模拟的基础,为迁飞性害虫异地预测提供一种有效的工具     

Convergent patterns of long-distance nocturnal migration in noctuid moths and passerine birds

Vast numbers of insects and passerines achieve long-distance migrations between summer and winter locations by undertaking high-altitude nocturnal flights. Insects such as noctuid moths fly relatively slowly in relation to the surrounding air, with airspeeds approximately one-third of that of passerines. Thus, it has been widely assumed that windborne insect migrants will have comparatively little control over their migration speed and direction compared with migrant birds. We used radar to carry out the first comparative analyses of the flight behaviour and migratory strategies of insects and birds under nearly equivalent natural conditions. Contrary to expectations, noctuid moths attained almost identical ground speeds and travel directions compared with passerines, despite their very different flight powers and sensory capacities. Moths achieved fast travel speeds in seasonally appropriate migration directions by exploiting favourably directed winds and selecting flight altitudes that coincided with the fastest air streams. By contrast, passerines were less selective of wind conditions, relying on self-powered flight in their seasonally preferred direction, often with little or no tailwind assistance. Our results demonstrate that noctuid moths and passerines show contrasting risk-prone and risk-averse migratory strategies in relation to wind. Comparative studies of the flight behaviours of distantly related taxa are critically important for understanding the evolution of animal migration strategies.     

迁飞过程中昆虫的行为:对风温场的适应与选择

本文综述了昆虫在迁飞过程中对大气物理环境的各种行为反应,有边界层气象的理论重新审视迁飞种群的时空分布,提出了“边界层顶现象”的概念。即边界层顶的低空逆温和低空急流为迁飞种群提供了最适宜的风温场,迁飞种群在边界层顶集聚成层,并通过定向理一步修饰其位移方位,表现出对风温场的主动选择能力和对大气结构和运动的高度复杂的适应性反应。进一步深化对“边界层顶现象”的认识,对迁飞性害虫的异地预测具有重要的理论意义     

昆虫迁飞行为的参数化Ⅱ.模式与检验

对通过昆虫迁飞行为分析得到的迁飞时间参数、高度参数、速度和方向参数等分别以一定的数学形式加以表达。其中,起飞时间以日出日没及晨昏朦影时刻为基准,用天文公式求出;边界层顶与飞行低温阈限所在高度及运行高度上的风速、风向由一维湍能（ＴＫＥ）模式以Ｅ－ε闭合做数值模拟：对飞行力较弱的小型或微小昆虫做随风运行处理,而对大型昆虫则根据其自身的飞行速度和定向方位与其飞行高度上的风向风速做矢量运算,求得位移方向和速度。通过我国小地老虎和草地螟标放回收试验结果的检验,表明本文提出的迁飞行为参数化方案是合理可行的。以此为基础组建数值模型进行昆虫迁飞轨迹分析,可望进一步提高迁飞性害虫异地预测的水平     

Influence of weather conditions on the flight of migrating black storks

This study tested the potential influence of meteorological parameters (temperature, humidity, wind direction, thermal convection) on different migration characteristics (namely flight speed, altitude and direction and daily distance) in 16 black storks (Ciconia nigra). The birds were tracked by satellite during their entire autumnal and spring migration, from 1998 to 2006. Our data reveal that during their 27-day-long migration between Europe and Africa (mean distance of 4100 km), the periods of maximum flight activity corresponded to periods of maximum thermal energy, underlining the importance of atmospheric thermal convection in the migratory flight of the black stork. In some cases, tailwind was recorded at the same altitude and position as the birds, and was associated with a significant rise in flight speed, but wind often produced a side azimuth along the birds'' migratory route. Whatever the season, the distance travelled daily was on average shorter in Europe than in Africa, with values of 200 and 270 km d⁻¹, respectively. The fastest instantaneous flight speeds of up to 112 km h⁻¹ were also observed above Africa. This observation confirms the hypothesis of thermal-dependant flight behaviour, and also reveals differences in flight costs between Europe and Africa. Furthermore, differences in food availability, a crucial factor for black storks during their flight between Europe and Africa, may also contribute to the above-mentioned shift in daily flight speeds.     

Noctuid migration in Texas within the nocturnal aeroecological boundary layer

Long-distance migration of adult corn earworm moths (Helicoverpazea), and several other noctuid moth species, facilitates seasonalexpansion of pest populations and consequent increased infestationsof agricultural crops on a continental scale in North America.Long-term field studies of population dynamics and migratoryflights of H. zea and fall armyworm (Spodoptera frugiperda)in the United States were evaluated using X-band radar observationsand profiles of atmospheric conditions. These studies identifiedcharacteristic patterns of migratory flight that are largelyassociated with vertical profiles of temperature and wind speed.Collective patterns of moth migrations were generally highlycorrelated with wind headings, but often at a significant angulardeviation. Preliminary analyses are presented between moth distributionsin the aerosphere estimated from discrete moth counts usingX-band radar and bulk reflectivity data from NEXRAD Dopplerradar. Identification of associations between atmospheric factorsand noctuid population dynamics and migratory flights will improvethe ability to predict infestations by pest species throughouttheir broad seasonal range expansion.     

Birds: blowin’ by the wind?

Migration is a task that implies a route, a goal and a period of time. To achieve this task, it requires orientation abilities to find the goal and energy to cover the distance. Completing such a journey by flying through a moving airspace makes this relatively simple task rather complex. On the one hand birds have to avoid wind drift or have to compensate for displacements to reach the expected goal. On the other hand flight costs make up a large proportion of energy expenditure during migration and, consequently, have a decisive impact on the refuelling requirements and the time needed for migration. As wind speeds are of the same order of magnitude as birds’ air speeds, flight costs can easily be doubled or, conversely, halved by wind effects. Many studies have investigated how birds should or actually do react to winds aloft, how they avoid additional costs or how they profit from the winds for their journeys. This review brings together numerous theoretical and empirical studies investigating the flight behaviour of migratory birds in relation to the wind. The results of these studies corroborate that birds select for favourable wind conditions both at departure and aloft to save energy and that for some long-distance migrants a tail-wind is an indispensable support to cover large barriers. Compensation of lateral wind drift seems to vary between age classes, depending on their orientation capacities, and probably between species or populations, due to the variety of winds they face en route. In addition, it is discussed how birds might measure winds aloft, and how flight behaviour with respect to wind shall be tested with field data.     

Wing size but not wing shape is related to migratory behavior in a soaring bird

Both wing size and wing shape affect the flight abilities of birds. Intra and inter‐specific studies have revealed a pattern where high aspect ratio and low wing loading favour migratory behaviour. This, however, have not been studied in soaring migrants. We assessed the relationship between the wing size and shape and the characteristics of the migratory habits of the turkey vulture Cathartes aura, an obligate soaring migrant. We compared wing size and shape with migration strategy among three fully migratory, one partially migratory and one non‐migratory (resident) population distributed across the American continent. We calculated the aspect ratio and wing loading using wing tracings to characterize the wing morphology. We used satellite‐tracking data from the migratory populations to calculate distance, duration, speed and altitude during migration. Wing loading, but not aspect ratio, differed among the populations, segregating the resident population from the completely migratory ones. Unlike what has been reported in species using flapping flight during migration, the migratory flight parameters of turkey vultures were not related to the aspect ratio. By contrast, wing loading was related to most flight parameters. Birds with lower wing loading flew farther, faster, and higher during their longer journeys. Our results suggest that wing morphology in this soaring species enables lower‐cost flight, through low wing‐loading, and that differences in the relative sizes of wings may increase extra savings during migration. The possibility that wing shape is influenced by foraging as well as migratory flight is discussed. We conclude that flight efficiency may be improved through different morphological adaptations in birds with different flight mechanisms.     

昆虫定向机制研究进展

许多昆虫具有定向运动的行为。对部分社会性昆虫和迁飞性昆虫定向行为的大量研究已经初步阐明太阳、地磁场、天体、风及地面标志物等都可能成为昆虫返巢和迁飞定向的线索。社会性昆虫具有对不同定向线索进行整合而实现精确导航的能力。日间迁飞性昆虫利用时间补偿太阳罗盘进行定向的机制亦已明确,但夜间迁飞昆虫的定向机制尚需深入研究。迁飞性害虫定向机制的明确将有助于判断害虫迁飞路径及降落区域,为迁飞害虫的准确预测提供科学依据。本文对昆虫的定向机制研究进展进行了综述。     

Barometer logging reveals new dimensions of individual songbird migration

Recent advances in tracking technology are based on the use of miniature sensors for recording new aspects of individual migratory behaviour. In this study, we have used activity data loggers with barometric and temperature sensors to record the flight altitudes as well as ground elevations during stationary periods of migratory songbirds. We tracked one individual of red‐backed shrike and one great reed warbler along their autumn migration from Europe to Africa. Both individuals performed their migration stepwise in travel segments and climbed most metres during the passage across the Mediterranean Sea and the Sahara Desert and least metres during the first flight segment in Europe. The great reed warbler reached its highest flight altitude of 3950 m a.s.l. during the travel segment from Europe to west Africa, while the red‐backed shrike reached 3650 m a.s.l as maximum flight altitude during its travel segment from Sahel to southern Africa. Both individuals used both lowlands and highlands for resting periods along their migrations. Furthermore, temperature decreased with increasing altitude during migratory flights for both individuals, highlighting the potential to determine flight duration from temperature measurements. Finally, we discuss how barometric data could be used to investigate birds’ responses to changes in air pressure as a cue for departures on migratory flights. This new technique, i.e. using a miniature data logger with barometric pressure sensor to estimate flight altitudes and ground elevations, will open up new avenues for research and importantly advance our understanding on how small birds behave during migratory flights.     

The problem of estimating wind drift in migrating birds

Whether migrating birds compensate for wind drift or not is a fundamental question in bird migration research. The procedures to demonstrate and quantitatively estimate wind drift or compensation are fraught with difficulties and pitfalls. In this paper, we evaluate four methods that have been used in several studies over the past decades. We evaluate the methods by analysing a model migratory movement with a realistic scatter in flight directions, for the ideal cases of full drift and complete compensation. Results obtained with the different methods are then compared with the "true behaviour" of the model movement, illustrating that spurious patterns of drift and compensation arise in some cases. We also illustrate and evaluate the different methods of estimating drift for a real case, based on tracking radar measurements of bird migration in relation to winds. Calculating the linear regression of mean geographic track (resulting flight direction) and heading directions (directions of the birds' body axis) of a migratory movement under different wind conditions in relation to the angle alpha (the angle between mean track and heading) always provides robust and reliable results. Comparing mean flight directions between occasions with winds from the left and right of the mean flight direction of the whole migratory movement also always provides expected and correct measures of drift. In contrast, regressions of individual flight directions in relation to alpha (the angle between track and heading for the specific individuals or flocks) are liable to produce biased and spurious results, overestimating compensation/overcompensation if following winds dominate in the analysis and overestimating drift/overdrift if opposed winds are dominating. Comparing mean directions for cases with winds from the left and right in relation to individual flight directions also gives biased and spurious results unless there is full variation in wind directions or an equal distribution of crosswinds from left and right. The results of the methodological evaluation and the analysis of the real case indicate that some earlier analyses of wind drift may have to be re-evaluated.     

蚜虫迁飞的研究进展

蚜虫的迁飞能造成危害扩展、病毒病传播和防碍人们的正常生活。蚜虫迁飞有其生理生态基础。寄主营养、蚜群拥挤度、天敌以及气候条件是刺激有翅蚜产生的主因素。蚜虫迁飞与卵巢发育存在明显的共轭关系。蚜虫迁飞多发生在晴朗的白天 ,并且温度、光照和风是影响迁飞行为的主导因子。蚜虫可上升到逆温层并随气流迁飞到上百公里以外的地方。目前 ,昆虫雷达观察、天气学分析和分子生物学方法已应用于蚜虫迁学的研究中 ,文章对蚜虫迁飞的生理生态基础、迁飞行为、影响迁飞的生态因子以及研究方法进行了综述 ,以期为蚜虫这类小型昆虫的迁飞研究提供指导     

Migration by soaring or flapping: numerical atmospheric simulations reveal that turbulence kinetic energy dictates bee-eater flight mode

Aerial migrants commonly face atmospheric dynamics that may affect their movement and behaviour. Specifically, bird flight mode has been suggested to depend on convective updraught availability and tailwind assistance. However, this has not been tested thus far since both bird tracks and meteorological conditions are difficult to measure in detail throughout extended migratory flyways. Here, we applied, to our knowledge, the first comprehensive numerical atmospheric simulations by mean of the Regional Atmospheric Modeling System (RAMS) to study how meteorological processes affect the flight behaviour of migrating birds. We followed European bee-eaters (Merops apiaster) over southern Israel using radio telemetry and contrasted bird flight mode (flapping, soaring-gliding or mixed flight) against explanatory meteorological variables estimated by RAMS simulations at a spatial grid resolution of 250 × 250 m(2). We found that temperature and especially turbulence kinetic energy (TKE) determine bee-eater flight mode, whereas, unexpectedly, no effect of tailwind assistance was found. TKE during soaring-gliding was significantly higher and distinct from TKE during flapping. We propose that applying detailed atmospheric simulations over extended migratory flyways can elucidate the highly dynamic behaviour of air-borne organisms, help predict the abundance and distribution of migrating birds, and aid in mitigating hazardous implications of bird migration.     

Resolving the heading‐direction ambiguity in vertical‐beam radar observations of migrating insects

相似文献   

Wind tunnel as a tool in bird migration research

Wind tunnels, in which birds fly against an artificially generated air flow, have since long been used to evaluate aerodynamic properties of steady bird flight. A new generation of wind tunnels has also allowed the many processes associated with migratory flights to be studied in captivity. We review how wind tunnel studies of aerodynamics and migratory performance together have helped advancing our understanding of bird migration. Current migration theory is based on the power‐speed relationship of flight as well as flight range equations, both of which can be evaluated using birds flying in wind tunnels. In addition, and depending on wind tunnel properties, performance during gliding and climbing flight, and effects of air pressure, humidity and turbulence on bird flight has been measured. Long‐distance migrant species have been flown repeatedly for up to 16 h non‐stop, allowing detailed studies of the energy expenditure, fuel composition, protein turnover, water balance, immunocompetence and stress associated with sustained migratory flights. In addition, wind tunnels allow the fuelling periods between migratory flights to be studied from new angles. We end our review by suggesting several important topics for future wind tunnel studies, ranging from on of the key questions remaining, the efficiency at which chemical power in converted to mechanical power, to new useful avenues, such as improving and calibrating the techniques used for tracking of individual birds in the wild.     

Goose parents lead migration V

Many migratory animals travel in large social groups. Large, avian migrants that fly in V-formations were proposed do so for energy saving by the use of up-wash by following individuals and regularly change leadership. As groups have been rather homogeneous in previous work, we aimed to explore leadership and its flight mechanics consequences in an extremely heterogeneous case of social migration, namely in spring migration of goose families. In families the experience of group members differs strongly and inclusive fitness may be important. We successfully collected overlapping spring migration tracking data of a complete family of greater white-fronted geese Anser a. albifrons and extracted leadership, flapping frequency and wind conditions in flight. Our data revealed V-formations where one parent was flying in front at all times. Although the father led the family group most of the time, he did not flap at higher frequency while doing so. In contrast, the mother flapped faster when leading, possibly because she experienced less supportive wind conditions than when the father led. We argue that in heterogeneous, social groups leadership might be fixed and not costly if supportive environmental conditions like wind can be used.     

Modeling the Distribution of Migratory Bird Stopovers to Inform Landscape-Scale Siting of Wind Development

Conservation of migratory birds requires understanding the distribution of and potential threats to their migratory habitats. However, although migratory birds are protected under international treaties, few maps have been available to represent migration at a landscape scale useful to target conservation efforts or inform the siting of wind energy developments that may affect migratory birds. To fill this gap, we developed models that predict where four groups of birds concentrate or stopover during their migration through the state of Wyoming, USA: raptors, wetland, riparian and sparse grassland birds. The models were based on existing literature and expert knowledge concerning bird migration behavior and ecology and validated using expert ratings and known occurrences. There was significant agreement between migratory occurrence data and migration models for all groups except raptors, and all models ranked well with experts. We measured the overlap between the migration concentration models and a predictive model of wind energy development to assess the potential exposure of migratory birds to wind development and illustrate the utility of migratory concentration models for landscape-scale planning. Wind development potential is high across 15% of Wyoming, and 73% of this high potential area intersects important migration concentration areas. From 5.2% to 18.8% of each group’s important migration areas was represented within this high wind potential area, with the highest exposures for sparse grassland birds and the lowest for riparian birds. Our approach could be replicated elsewhere to fill critical data gaps and better inform conservation priorities and landscape-scale planning for migratory birds.     

Variation in the mechanical properties of flight feathers of the blackcap Sylvia atricapilla in relation to migration

Migration causes temporal and energetic constraints during plumage development, which can compromise feather structure and function. In turn, given the importance of a good quality of flight feathers in migratory movements, selection may have favoured the synthesis of feathers with better mechanical properties than expected from a feather production constrained by migration necessities. However, no study has assessed whether migratory behaviour affects the relationship between the mechanical properties of feathers and their structural characteristics. We analysed bending stiffness (a feather mechanical property which is relevant to birds’ flight), rachis width and mass (two main determinants of variation in bending stiffness) of wing and tail feathers in migratory and sedentary blackcaps Sylvia atricapilla. Migratory blackcaps produced feathers with a narrower rachis in both wing and tail, but their feathers were not significantly lighter; in addition, bending stiffness was higher in migratory blackcaps than in sedentary blackcaps. Such unexpected result for bending stiffness remained when we statistically controlled for individual variation in rachis width and feather mass, which suggests the existence of specific mechanisms that help migratory blackcaps to improve the mechanical behaviour of their feathers under migration constraints.     

Field studies of avian nocturnal migratory orientation II. Experimental manipulation of orientation in white-throated sparrows (Zonotrichia albicollis) released aloft

Migrant white-throated sparrows (Zonotrichia albicollis) were released from boxes carried aloft by balloon and tracked with radar. All birds were released on clear nights when winds were light and opposed to the normal migration direction for the season. Birds were treated in one of two ways: Lens birds were fitted with frosted lenses prior to release; No Lens birds were released without lenses. No Lens birds that engaged in straight and level flight generally headed in the predicted migratory direction and as a group were not oriented with respect to wind direction. Lens birds did not head in the predicted migratory direction, but instead oriented downwind. This orientation behaviour is consistent with the relationship of orientation cues inferred from the field observations described in part I of this paper. The data show that flying birds deprived of all detailed form vision can determine wind direction.