Estimating updraft velocity components over large spatial scales: contrasting migration strategies of golden eagles and turkey vultures

Soaring birds migrate in massive numbers worldwide. These migrations are complex and dynamic phenomena, strongly influenced by meteorological conditions that produce thermal and orographic uplift as the birds traverse the landscape. Herein we report on how methods were developed to estimate the strength of thermal and orographic uplift using publicly available digital weather and topography datasets at continental scale. We apply these methods to contrast flight strategies of two morphologically similar but behaviourally different species: golden eagle, Aquila chrysaetos, and turkey vulture, Cathartes aura, during autumn migration across eastern North America tracked using GPS tags. We show that turkey vultures nearly exclusively used thermal lift, whereas golden eagles primarily use orographic lift during migration. It has not been shown previously that migration tracks are affected by species-specific specialisation to a particular uplift mode. The methods introduced herein to estimate uplift components and test for differences in weather use can be applied to study movement of any soaring species.     

Where eagles soar: Fine‐resolution tracking reveals the spatiotemporal use of differential soaring modes in a large raptor

Unlike smaller raptors, which can readily use flapping flight, large raptors are mainly restricted to soaring flight due to energetic constraints. Soaring comprises of two main strategies: thermal and orographic soaring. These soaring strategies are driven by discrete uplift sources determined by the underlying topography and meteorological conditions in an area. High‐resolution GPS tracking of raptor flight allows the identification of these flight strategies and interpretation of the spatiotemporal occurrence of thermal and orographic soaring. In this study, we develop methods to identify soaring flight behaviors from high‐resolution GPS tracking data of Verreaux’s eagle Aquila verreauxii and analyze these data to understand the conditions that promote the use of thermal and orographic soaring. We use these findings to predict the use of soaring flight both spatially (across the landscape) and temporally (throughout the year) in two topographically contrasting regions in South Africa. We found that topography is important in determining the occurrence of soaring flight and that thermal soaring occurs in relatively flat areas which are likely to have good thermal uplift availability. The predicted use of orographic soaring was predominately determined by terrain slope. Contrary to our expectations, the topography and meteorology of eagle territories in the Sandveld promoted the use of soaring flight to a greater extent than in territories in the more mountainous Cederberg region. Spatiotemporal mapping of predicted flight behaviors can broaden our understanding of how large raptors like the Verreaux’s eagle use their habitat and how that links to energetics (as the preferential use of areas that maximize net energy gain is expected), reproductive success, and ultimately population dynamics. Understanding the fine‐scale landscape use and environmental drivers of raptor flight can also help to predict and mitigate potential detrimental effects of anthropogenic developments, such as mortality via collision with wind turbines.     

昆虫飞行速度和持续时间监测仪硬件设计

本文设计了利用微机记录昆虫飞行状态的实验装置,这种装置由两部分组成,一部分是设计和制作一个飞行磨供昆虫飞行,另一部分是制作光电传感器和微机检测系统,记录信号并把信号进行识别、分析、归类,送往计算机显示和打印。介绍了其工作原理和使用方法。     

Comparative flight behavior of Diabrotica virgifera virgifera and Diabrotica barberi in the laboratory

A tethered flight system was used to characterize and compare the flight behavior of western, Diabrotica virgifera virgifera LeConte (WCR), and northern, Diabrotica barberi (Smith and Lawrence) (NCR), corn rootworms in the laboratory. Distributions of flight durations were skewed towards short flights for both species regardless of sex or age and there was high variability in flight durations and frequency in individual beetles. Flight distributions for WCR were distinctly bimodal, reflecting a dichotomy between short trivial flights and much longer sustained flights. Trivial flight performance did not vary with age but did differ between species. In comparison to WCR, NCR took shorter flights but had a higher frequency of flights over a 23-h period. Overall, WCR beetles logged substantially more flight time in the same period of time. The proportion of individual WCR undertaking sustained flight was relatively low (<24%) and, for females, declined along with sustained flight durations as a function of age. Periodicity of trivial flight did not differ betweer the species. In general, flight activity was greatest during early morning and early evening hours. No correlations were found between any feature of flight performance and body size or wing loading ratios.

---

Résumé Un système de vol captif a été utilisé pour caractériser et comparer au laboratoire les comportements de vol de D. virgifera virgifera et D. barberi. La distribution des durées de vol est nettement biaisée avec la grande majorité des vols durant moins d'une minute quels que soient le sexe et l'âge. Il y a une grande variabilité interindividuelle tant en durée qu'en fréquence de vol. Les distributions des durées de vol en fonction du sexe sont bimodales chez D. virgifera virgifera, mais pas chez D. barberi, ce qui reflète la séparation entre vols brefs ordinaires et long vols prolongés. Les vols brefs ordinaires ne dépendent pas beaucoup de l'âge ou du sexe mais diffèrent suivant l'espèce. D. barberi a eu des vols plus brefs, mais en a effectué plus pendant une période de 23 heures. Au total, D. virgifera virgifera a consacré nettement plus de temps au vol pendant la même période; mais, chez cette espèce la proportion d'individus effectuant des vols soutenus était relativement faible (<24%), avec une diminution de leur nombre avec l'âge chez les femelles; le nombre le plus élevé étant chez les jeunes femelles. La périodicité des vols ordinaires n'a dépendu ni du sexe, ni de l'espèce; l'activité de vol a été en général plus importante tôt le matin et en début de soirée. Aucune corrélation n'a été trouvée entre une quelconque performance de vol et la taille du corps ou la charge alaire.

     

Nutrition‐ and sex‐dependent utilization of body resources in relation to reproduction in a scorpionfly

Reproduction often comes at a cost of a reduction in body functions. In order to enhance their reproductive output, some insect species degenerate their thoracic muscles, typically resulting in reduced flight ability. From a life‐history trade‐off perspective, we expect the importance of body resource utilization to be amplified both with increased reproductive expenditure and with increased resource limitation. In this study, we measured age‐related changes in thorax weight, as a measure of flight muscle size, during a major part of the adult lifespan in males and females of the scorpionfly Panorpa vulgaris. The aim of the study was twofold: first to investigate whether scorpionflies have the potential to degenerate their flight muscles; second, and more importantly, to determine whether the magnitude of flight muscle degeneration is a plastic response in relation to resource availability, and if it differs between the sexes. The results clearly demonstrate that food availability does influence investment in flight muscle development. The build‐up of the thoracic muscles was strongly influenced by nutrient availability. Furthermore, the age‐related decrease in thorax weight was significantly different for males and females. Only females showed a strong age‐dependent decrease in thorax weight, indicative of muscle degeneration, yet no difference between food treatments was detected. For males, there was no significant directional change in thorax weight. Nevertheless, with increasing age, the difference in thorax weight between food treatments increased significantly. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 199–207.     

基于转录组测序的楚雄腮扁叶蜂飞行肌蛋白及飞行能量代谢相关酶挖掘

本研究旨在阐明楚雄腮扁叶蜂Cephalcia chuxiongica Xiao飞行肌结构蛋白及飞行能量代谢相关酶基因信息。首先采用电镜技术对楚雄腮扁叶蜂飞行肌进行了观察,结果表明,肌原纤维（由粗丝和细丝组成,其数量比例为1∶3）是飞行肌的基本成分,肌原纤维横切面平均面积为0.771±0.042 μm^2,肌节平均长度为2.698±0.116 μm。进一步通过飞行肌转录组分析,共筛选到11大类飞行肌结构蛋白,其中肌球蛋白（Myosin）和肌动蛋白（Actin）的转录本数较多,分别为127个和54个。发现1个飞行蛋白Flightin编码基因（可编码一个长152 aa的蛋白）,在该蛋白中检测到6个模体结构（Motif）,膜翅目昆虫中在Motif 1的一些位点上其氨基酸类型表现出明显的特异性。在楚雄腮扁叶蜂中筛选到了25个飞行能量代谢关键酶编码基因,并基于这些酶构建了三条飞行能量代谢途径,即糖酵解（涉及15种酶）、脂肪氧化（涉及6种酶）和脯氨酸氧化（涉及4种酶）。在楚雄腮扁叶蜂中发现4个3-磷酸甘油脱氢酶GPDH异构体,但并未在这些异构体中找到类似果蝇飞行肌GPDH异构体所具有的特异C端三联肽（QNL）,表明GPDH的进化存在物种特异性。     

Flocking behaviour in the twilight ascents of Common Swifts Apus apus

Among the many unique flight behaviours of Common Swifts Apus apus, the most puzzling may be their ascents to high altitudes during both dusk and dawn. Twilight ascents have been hypothesized to be functionally related to information acquisition, including integration of celestial orientation cues, high‐altitude visual landmarks and sampling of weather conditions. However, their exact purpose remains unknown. We tracked Common Swifts with tracking radar at their breeding grounds in southern Sweden, and present evidence that during the dusk ascent and dawn descent they often occur in flocks, whereas during the dusk descent and dawn ascent phase they do not. This flocking behaviour suggests that swifts may benefit from conspecific interactions during twilight ascents and descents, possibly through more robust cue acquisition and information exchange in groups, or extending social behaviour also seen in screaming parties before dusk.     

Variation in flight duration among individual Tetraopes beetles: Implications for studies of insect flight

Milkweed beetles, Tetraopes tetraophalmus (Forster) (Cerambycidae), were flight tested three times weekly throughout their lives. Flight durations peaked early in life and then declined rapidly with age. Significant variation existed (1) between individuals, with some flying for long periods of time, others for only a few seconds, and (2) within individuals, with some flying for long periods on some test days and very briefly or not at all on other days. Long and short fliers were indistinguishable on the basis of size, sex, or lifespan. The data show that studies of insect flight will underestimate the number of long fliers in a population by as much as 50% or more unless individuals are flight tested more than once.     

棉铃虫的飞翔活动

实验研究表明,棉铃虫初羽化个体极少活动,１日龄以后活动趋于频繁。个体日活动以２０：００￣２１：００和３：００￣５：００为２个高峰期,１￣３日龄主要以交配和觅食为主,４日龄以后多表现产卵活动。３￣６日龄成虫的飞翔能力最强,连续吊飞第６日龄个体,其平均累计飞行时间达４１．３０ｈ,平均飞行距离２３９．７ｋｍ,个体最远飞行距离３１１．２９ｋｍ,最长飞行时间５９．６８ｈ,最大飞行速度３．２１ｍ／ｓ。棉铃虫在     

Colonisation ability of the threatened tenebrionid beetle Oplocephala haemorrhoidalis and its common relative Bolitophagus reticulatus

Abstract. 1. Life-history traits associated with colonisation ability were compared in the threatened tenebrionid beetle Oplocephala haemorrhoidalis and its common relative Bolitophagus reticulatus . Both species feed and breed exclusively in fruiting bodies of the wood-decaying fungus Fomes fomentarius .
2. The presence and status of flight wings, flight muscles, and mature eggs were determined by dissection. Flight willingness was studied in a field experiment, and flight duration in a flight-mill experiment.
3. Females of O. haemorrhoidalis had fewer but larger eggs in their abdomen than B. reticulatus females.
4. All beetles of both species had fully developed flight wings but a larger proportion of B. reticulatus than O. haemorrhoidalis had developed flight muscles.
5. Bolitophagus reticulatus was more willing to take off than O. haemorrhoidalis , however both species, especially O. haemorrhoidalis , were powerful fliers, with many individuals being able to fly several kilometres. Oplocephala haemorrhoidalis tended to make few flights of long duration whereas B. reticulatus made several, but mostly shorter, flights.
6. The results indicate that B. reticulatus has a suite of life-history traits that makes it better adapted than O. haemorrhoidalis to exploit the scattered trees with fruiting bodies present in managed forests. This may explain why O. haemorrhoidalis is restricted primarily to sites with a high density of suitable substrates that have been available continuously for a long time.     

Water balance in Rhodnius prolixus during flight: Quantitative aspects of diuresis and its relation to changes in haemolymph and flight-muscle water

The amount of water voided by male Rhodnius prolixus which were flown to exhaustion varied from 0 to over 10% of the initial live weight. It accounted for nearly all of the body water lost during the flight period. Simultaneous measurements on the loss of haemolymph water and an estimate of the amount of faecal water in the excreta indicated that the source of the voided water was primarily the haemolymph. The total water content of the flight muscles changed very little in insects which flew to exhaustion. It is concluded that, despite the diuresis and loss of water, and the considerable reduction in haemolymph volume, dehydration of the flight muscles of male R. prolixus does not occur during these flight periods, and is not a factor contributing to ‘exhaustion’. The possibility that insufficient haemolymph is a factor limiting the duration of flight is discussed.     

Flight-phase and visual-field related optomotor yaw responses in gregarious desert locusts during tethered flight

Tethered flying desert locusts, Schistocerca gregaria, generate yaw-torque in response to rotation of a radial grating located beneath them. By screening parts of the pattern, rotation of the unscreened grating turned out to induce a compensatory steering (by pattern motion within transversally oriented 90° wide sectors) as well as an upwind/downwind turning response (by pattern motion within the anterior ventral 90° wide sector). The strength and polarity of responses upon the unscreened grating results from a linear superposition of these two response components. The results are discussed with regard to a functional specialization of eye regions.In a typical experiment, 3 consecutive flight-phases, assumed to mirror start, long-range flight, and landing of a free-flying locust, were distinguished. They may result from a time dependent variation of the polarity and relative strength of upwind/downwind turning and compensatory steering responses. Starting and landing phases were under strong optomotor control and were dominated by the high-gain compensatory steering. In contrast, the phase of long-range flight was under weak optomotor control resulting from a low gain in both of the two response components. The biological significance of this variable strength of optomotor control on free flight orientation of swarming locusts is discussed.     

Analysis of Maneuvering Flight of an Insect

Wing motion of a dragonfly in the maneuvering flight, which was measured by Wang et al. was investigated. Equations of motion for a maneuvering flight of an insect were derived. These equations were applied for analyzing the maneuvering flight. Inertial forces and moments acting on a body and wings were estimated by using these equations and the measured motions of the body and the wings. The results indicated the following characteristics of this flight: ( 1 ) The phase difference in flapping motion between the two fore wings and two hind wings, and the phase difference between the flapping motion and the feathering motion of the four wings are equal to those in a steady forward flight with the maximum efficiency. (2)The camber change and the feathering motion were mainly controlled by muscles at the wing bases.     

南京地区棉蚜的飞行活动节律及其飞行能力

昆虫的飞行活动规律及飞行能力是研究其能否迁飞的基础。通过采用春季到秋季20 m高空黄盆诱蚜、高空所诱蚜和春季木槿树上有翅蚜的卵巢解剖,以及春夏秋三季田间有翅蚜的吊飞试验等方法,研究了南京地区棉蚜Aphis gossypii的飞行活动节律和飞行能力。结果表明,有翅棉蚜的日羽化高峰出现在19:00～20:00。2001年南京地区棉蚜的春、秋两季迁飞高峰分别在5月8日和10月25日。5月份高空诱集的棉蚜中,95.7%个体的卵巢小管数在7条以下,而木槿上羽化后1天的有翅蚜中有35.2%个体的卵巢小管数在7条以上;高空诱蚜和木槿上蚜的平均卵巢小管数存在极显著差异,分别为3.94±1.65和5.88±1.92。8月中下旬棉田棉蚜存在低空飞行行为,并且出现飞行高峰时有翅蚜的卵巢小管数平均在6条以下,超过6条则停止飞行。羽化后1～2天有翅棉蚜吊飞个体的飞行比率和平均飞行距离表现为春、秋季显著大于夏季,三季的最长飞行距离分别为3.89 km、6.15 km和1.44 km。     

适用于蚜虫等微小昆虫的飞行磨系统

介绍了一套采用计算机进行控制和数据采集的适用于蚜虫等微小昆虫的飞行磨系统。该系统能同时对32头昆虫进行飞行测试,并对测试数据进行自动分析处理。利用该飞行磨系统对不同日龄禾缢管蚜的飞行能力进行了初步测试。结果表明,禾缢管蚜在第1至第5日龄的飞行能力最强,明显高于第7和第9日龄。平均飞行时间在各日龄之间差异不显著,但平均飞行速度随日龄的增加而逐渐降低。本文对飞行磨结构、数据采集接口板电路原理和软件流程设计等方面均进行了较为详细的介绍。并简要介绍了不同日龄禾缢管蚜的飞行能力测试结果。对开展微小型昆虫的飞行行为学研究具有较为重要的参考价值。     

Optimal flight behavior of soaring migrants: a case study of migrating steppe buzzards, Buteo buteo vulpinus

This article presents tests of the theoretical predictions onoptimal soaring and gliding flight of large, diurnal migrantsusing Pennycuick's program 2 for "bird flight performance."Predictions were compared with 141 observed flight paths ofmigrating steppe buzzards, Buteo buteo vulpinus. Calculationsof cross-country speed relative to the air included bird's airspeedsand sinking rates in interthermal gliding and climbing ratesin thermal circling. Steppe buzzards adjusted interthermal glidingairspeed . according to their actual climbing rate in thermalcircling. By optimizing their gliding airspeed, the birds maximizedtheir crosscountry performance relative to the air. Despitethis general agreement with the model, there was much scatterin the data, for the model neglects horizontal winds and updraftsduring the gliding phase. Lower sinking rates due to updraftsduring the gliding phases allowed many birds to achieve highercross-country speeds than predicted. In addition, birds reactedto different wind directions and speeds: in side and opposingwinds, the steppe buzzards compensated for wind displacementduring soaring and increased their gliding airspeed with decreasingtailwind component Nevenheless, cross-country speed relativeto the ground, which is the important measure for a migratorybird, was still higher under following winds. This study showsthat Pennycuick's program 2 provides reliable predictions onoptimal soaring and gliding behavior using realistic assumptionsand constants in the model, but a great deal of variation aroundthe mean is generated by factors not included in the model     

Heritability of flight and resting metabolic rates in the Glanville fritillary butterfly

Dispersal capacity is a key life‐history trait especially in species inhabiting fragmented landscapes. Evolutionary models predict that, given sufficient heritable variation, dispersal rate responds to natural selection imposed by habitat loss and fragmentation. Here, we estimate phenotypic variance components and heritability of flight and resting metabolic rates (RMRs) in an ecological model species, the Glanville fritillary butterfly, in which flight metabolic rate (FMR) is known to correlate strongly with dispersal rate. We modelled a two‐generation pedigree with the animal model to distinguish additive genetic variance from maternal and common environmental effects. The results show that FMR is significantly heritable, with additive genetic variance accounting for about 40% of total phenotypic variance; thus, FMR has the potential to respond to selection on dispersal capacity. Maternal influences on flight metabolism were negligible. Heritability of flight metabolism was context dependent, as in stressful thermal conditions, environmentally induced variation dominated over additive genetic effects. There was no heritability in RMR, which was instead strongly influenced by maternal effects. This study contributes to a mechanistic understanding of the evolution of dispersal‐related traits, a pressing question in view of the challenges posed to many species by changing climate and fragmentation of natural habitats.     

Effects of flight training on flight speed and substrate utilization in locusts

ABSTRACT. Regular flight exercise of adult male Locusta migratoria migratorioides (R and F) accelerated the development of maximum flight speed and disrupted the development of the typical pattern of change of flight speed exhibited when normal (untrained) adult male laboratory locusts are flown on roundabouts. Thus, while untrained mature locusts fly fast initially and then slow to a steady cruising speed after 20 min, trained locusts flew at a relatively constant speed throughout a 60-min test period. Flight training also led to a marked reduction in the size of the fat body and the flight muscles, but flight muscle ultrastructural development was not affected. Regular flight exercise had no long-term effect on haemolymph carbohydrate concentration but lipid levels were significantly depressed.     

大头金蝇的飞行能力

通过飞行磨测定和扩散观察,研究大头金蝇Chrysomya megacephala(Fabricius)的飞行能力。结果表明:雌、雄虫的平均飞行距离、平均最大飞行速度、平均飞行时间间没有显著的差异。大头金蝇的平均飞行距离25℃时达最高,为4·4783km,之后随着温度的进一步增高而逐渐下降;平均飞行时间20℃时最大,为1·2262h;最大飞行速度25℃最大,为1·2210m/s。50%,60%,70%和80%相对湿度的平均飞行距离有显著差异,分别为5·7475,0·7913,0·3850和0·7575km;50%RH的平均飞行时间最长为2·7868h,平均最大飞行速度中80%RH最高,为2·0792m/s。在塑料大棚(长30m)释放大头金蝇呈扇形扩散,最快速度0·3m/s,从一端扩散到塑料大棚的另一端所需时间平均为(2·52±0·63)min,最长需要3·08min,表现出大头金蝇有较强的飞行能力。     

Avian furcula morphology may indicate relationships of flight requirements among birds

This study examined furcula (wishbone) shape relative to flight requirements. The furculae from 53 museum specimens in eight orders were measured: 1) three-dimensional shape (SR) as indicated by the ratio of the direct distance between the synostosis interclavicularis and the ligamentous attachment of one of its clavicles to the actual length of the clavicle between those same two points, and 2) curvature within the primary plane (LR) as indicated by the ratio of the length of the clavicle to the sum of the orthogonal distances between the same points using a projected image. Canonical discriminant analysis of these ratios placed the individuals into a) one of four general flight categories and b) one of eight taxonomic orders. The four flight categories were defined as: i) soaring with no flapping, ii) flapping with no soaring, iii) subaqueous (i.e., all wingbeats taking place under water), and iv) partial subaqueous (i.e., wingbeats used for both aerial and submerged flapping). The error rate for placement of the specimens in flight categories was only 26.4%, about half of the error rate for placement in taxonomic orders (51.3%). Subaqueous fliers (penguins, great auks) have furculae that are the most V-shaped. Partial subaqueous fliers (alcids, storm petrels) have furculae that are more U-shaped than the subaqueous fliers but more V-shaped than the aerial flapping fliers. The partial subaqueous fliers have furculae that are also the most anteriorly curved, possibly increasing protraction capability by changing the angle of applied force and increasing attachment area for the origin of the sternobrachialis pectoralis. The increased protraction capability can counteract profile drag, which is greater in water than in air due to the greater density of water. Soaring birds have furculae that are more U-shaped or circular than those of flapping birds and have the smallest range of variation. These results indicate that the shape of the furcula is functionally related to general differences in flight requirements and may be used to infer relationships of these requirements among birds.