Hymenopteran wing kinematics: a qualitative study

(With 9 plates and 2 figures in the text)
Wing deformations were studied in representatives of several hymenopteran families during free Right in hovering or near hovering conditions. The claval furrow, costal break, stigma and a variety of flexion lines occupying the wing apex are all involved in regulating forewing profile during the flight cycle in lchneumonidae and Tenthredinidae. In these families, as well as in the sphecid Sphex rujocincius , the median flexion line of the hindwing is also active in the terminal stages of supination. The plaiting fold of the vespid forewing plays an important role in profile control during the upstroke, reversing its polarity compared to rest. Little wing distortion was observed in the large scolids Scotia flavifrons and S. hirta , possibly attributable to the presence of strengthening ridges and grooves in the wing apex.     

Kinematics of take-off and climbing flight in butterflies

High speed flash photography (flash duration 0.1 ms) was used to analyse wing movements in over 30 species of butterfly. With few exceptions, the insects showed a clap and peel mechanism of lift production at the start of the downstroke. Early in the upstroke the wings showed pronounced ventral flexure which, combined with inertial lag in the posterior parts of both wing pairs and delayed supination in the hind wing, led to the formation of a funnel-like space between the wings. These movements, and the resultant airflow patterns, appear to be an axi-symmetric equivalent of the 'near' clap and peel (here referred to as the funnel). Hind wing movements throughout the stroke are hinged upon the claval furrow. The expanded anal lobes of the hind wing lying medially to the claval furrow help to provide an air-tight seal around the abdomen between the upper and lower wing surfaces, which increases the efficiency of the peel and funnel mechanisms. The role of the intercalary flexion lines in controlling changes in wing surface corrugation during the cycle is also investigated.     

Direct measurements of the kinematics and dynamics of bat flight

Experimental measurements and analysis of the flight of bats are presented, including kinematic analysis of high-speed stereo videography of straight and turning flight, and measurements of the wake velocity field behind the bat. The kinematic data reveal that, at relatively slow flight speeds, wing motion is quite complex, including a sharp retraction of the wing during the upstroke and a broad sweep of the partially extended wing during the downstroke. The data also indicate that the flight speed and elevation are not constant, but oscillate in synchrony with both the horizontal and vertical movements of the wing. PIV measurements in the transverse (Trefftz) plane of the wake indicate a complex 'wake vortex' structure dominated by a strong wing tip vortex shed from the wing tip during the downstroke and either the wing tip or a more proximal joint during the upstroke. Data synthesis of several discrete realizations suggests a 'cartoon' of the wake structure during the entire wing beat cycle. Considerable work remains to be done to confirm and amplify these results.     

Comparative functional morphology of the wings of Diptera

Wings of representative species of the order Diptera were compared with a simple model structure in which corrugated spars diverge from a V-shaped leading edge spar. Both develop torsion and camber when subjected to aerodynamic loads, forming a propeller shape. Both the leading edge and the cubitus of flies' wings twist basally, allowing camber to be set up as the media hinges up or down at the arculus. Three different wing types were identified: stiff wings possessing two or three main spars; and wings capable of ventral flexion. In wings possessing only two spars, found mainly in the Nematocera, control of camber is achieved largely by the use of cross veins. Wing control and flight are generally imprecise. The third spar, found in most Brachycera, in the Syrphidae and in the Conopidae controls camber and helps support a broader wing. Finer control of camber is exerted by marginal cross veins, and these insects generally have precise, darting flight. Ventral flexion mechanisms are found in the Simuliidae, the Stratiomyiidae, and widely in the Schizophora. Control of ventral flexion, which occurs at the end of the downstroke, allows fast, unpredictable manoeuvres. Functional similarities indicate either phylogenetic relationship or convergence.     

Aerodynamic performance of a hovering hawkmoth with flexible wings: a computational approach

Insect wings are deformable structures that change shape passively and dynamically owing to inertial and aerodynamic forces during flight. It is still unclear how the three-dimensional and passive change of wing kinematics owing to inherent wing flexibility contributes to unsteady aerodynamics and energetics in insect flapping flight. Here, we perform a systematic fluid-structure interaction based analysis on the aerodynamic performance of a hovering hawkmoth, Manduca, with an integrated computational model of a hovering insect with rigid and flexible wings. Aerodynamic performance of flapping wings with passive deformation or prescribed deformation is evaluated in terms of aerodynamic force, power and efficiency. Our results reveal that wing flexibility can increase downwash in wake and hence aerodynamic force: first, a dynamic wing bending is observed, which delays the breakdown of leading edge vortex near the wing tip, responsible for augmenting the aerodynamic force-production; second, a combination of the dynamic change of wing bending and twist favourably modifies the wing kinematics in the distal area, which leads to the aerodynamic force enhancement immediately before stroke reversal. Moreover, an increase in hovering efficiency of the flexible wing is achieved as a result of the wing twist. An extensive study of wing stiffness effect on aerodynamic performance is further conducted through a tuning of Young's modulus and thickness, indicating that insect wing structures may be optimized not only in terms of aerodynamic performance but also dependent on many factors, such as the wing strength, the circulation capability of wing veins and the control of wing movements.     

Indirect closing of elytra by the prothorax in beetles (Coleoptera): general observations and exceptions

Voluntary movements of the prothorax and the elytra in tethered flying beetles and manually induced movements of these parts in fresh dead beetles were recorded in 30 species representing 14 families. Participation of prothoracic elevation in the closing of the elytra was demonstrated in three ways. (i) The elevation was always simultaneous with elytral closing, in contrast to depression and elytral opening; a rare exception occurred in Lucanus cervus, whose elytra sometimes started to close before the cessation of wing strokes and the elevation of the prothorax. (ii) The manipulated elevation always induced closing of the spread elytra; the mechanical interaction between the hind edge of the pronotum and the roots of the elytra is a universal mechanism of closing the elytra in beetles. (iii) The prevention of pronoto-elytral contact in live beetles by the excision of the hind edge of the pronotum in front of the root prevented elytral closing after normal flight. Exceptions to this rule included some beetles that were able to close their elytra after such an excision: tiger beetles and diving beetles (seldomly) and rose chafers (always). This ability in Adephaga may be explained by attachments of the muscle actuating the 4th axillary plate, which differ from the attachments in Polyphaga. Cetoniinae open their elytra only by a small amount. It is proposed that their small direct adductors in combination with the elasticity of the sclerites are enough to achieve elytral closing without additional help from the prothorax.     

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.     

The kinematics of Heteroptera in free flight

The kinematics of six species of Heteroptera in free flight are analysed and compared.

• (1) 

  Using nested analysis of variance techniques, statistically significant variation was detected between species for several of the flight parameters measured: mean angular velocity; pronation/supination ratio; upstroke/downstroke ratio; and wing beat frequency. In each case this is discussed in terms of variation in flight behaviour.
• (2) 

  Beneficial aerodynamic forces are generated during the upstroke and the downstroke, in both fast forward and rising flight.
• (3). 

  When the insects change from level, forward flight to near vertical, rising flight, the following parameters are altered in most of the sequences analysed:

• (a). 

  the stroke plane angle becomes steeply, negatively inclined, associated with an increase in body angle;
• (b). 

  the stroke amplitude is reduced;
• (c). 

  wing beat frequency is lowered, associated with a drop in mean angular velocity;
• (d). 

  the speed of stroke reversal (rotational velocity) is increased. This may be associated with increased wing torsion and tip flexion which in turn could improve any beneficial unsteady aerodynamic effects generated at stroke reversal.

The reasons for this change in flight performance and the deviations from that seen in other insects are discussed.
It is shown that Heteroptera may make use of wing drag in flight, particularly during rising flight.     

Flexible Wing Kinematics of a Free-Flying Beetle (Rhinoceros Beetle Trypoxylus Dichotomus)

Detailed 3-Dimensional (3D) wing kinematics was experimentally presented in free flight of a beetle,Trypoxylus dichotomus,which has a pair of elytra (forewings) and flexible hind wings.The kinematic parameters such as the wing tip trajectory,angle of attack and camber deformation were obtained from a 3D reconstruction technique that involves the use of two synchronized high-speed cameras to digitize various points marked on the wings.Our data showed outstanding characteristics of deformation and flexibility of the beetle's hind wing compared with other measured insects,especially in the chordwise and spanwise directions during flapping motion.The hind wing produced 16％ maximum positive camber deformation during the downstroke.It also experienced twisted shape showing large variation of the angle of attack from the root to the tip during the upstroke.     

Comparison of the Effects of Flexion and Extension of the Thumb and Fingers on the Position and Cross-Sectional Area of the Median Nerve

Objective

To assess the separate effects of thumb and finger extension/flexion on median nerve position and cross-sectional area.

Methods

Ultrasonography was used to assess median nerve transverse position and cross-sectional area within the carpal tunnel at rest and its movement during volitional flexion of the individual digits of the hand. Both wrists of 165 normal subjects (11 men, 4 women, mean age, 28.6, range, 22 to 38) were studied.

Results

Thumb flexion resulted in transverse movement of the median nerve in radial direction (1.2±0.6 mm), whereas flexion of the fingers produced transverse movement in ulnar direction, which was most pronounced during flexion of the index and middle fingers (3.2±0.9 and 3.1±1.0 mm, respectively). Lesser but still statistically significant movements were noted with flexion of the ring finger (2.0±0.8 mm) and little finger (1.2±0.5 mm). Flexion of the thumb or individual fingers did not change median nerve cross-sectional area (8.5±1.1 mm²).

Conclusions

Volitional flexion of the thumb and individual fingers, particularly the index and middle fingers, produced significant transverse movement of the median nerve within the carpal tunnel but did not alter the cross-sectional area of the nerve. The importance of these findings on the understanding of the pathogenesis of the carpal tunnel syndrome and its treatment remains to be investigated.     

Exploring bird aerodynamics using radio-controlled models

A series of radio-controlled glider models was constructed by duplicating the aerodynamic shape of soaring birds (raven, turkey vulture, seagull and pelican). Controlled tests were conducted to determine the level of longitudinal and lateral-directional static stability, and to identify the characteristics that allowed flight without a vertical tail. The use of tail-tilt for controlling small bank-angle changes, as observed in soaring birds, was verified. Subsequent tests, using wing-tip ailerons, inferred that birds use a three-dimensional flow pattern around the wing tip (wing tip vortices) to control adverse yaw and to create a small amount of forward thrust in gliding flight.     

Wing kinematics of avian flight across speeds

To test whether wing shape affects the kinematics of wing motion during bird flight, we recorded high-speed video (250 Hz) of four species flying in a variable-speed wind tunnel. The birds flew at intervals of 2 m s⁻¹, ranging from 1 m s⁻¹ up to their respective maximum flight speed, which varied from 14 to 17 m s⁻¹ depending on the species. Kinematic data obtained from two synchronized, high-speed video cameras were analyzed using 3D reconstruction. Three species with relatively pointed, high-aspect ratio wings changed wingbeat styles according to flight speed (budgerigar, Melopsittacus undulatus ; cockatiel, Nymphicus hollandicus ; ringed turtle dove, Streptopelia risoria ). These species used a wing-tip reversal upstroke, characterized by supination of the distal wing at mid-upstroke, at equivalent airspeeds ≤7 to 9 m s⁻¹. In faster flight, they used a swept-wing upstroke, without distal wing supination. At mid-upstroke at any speed, wingspan in these species was greater than wrist span. In contrast, at all steady flight speeds, the black-billed magpie Pica hudsonia with relatively broad, low-aspect ratio wings, used a flexed-wing, feathered upstroke in which wrist spans were equal to or greater than wingspans. Our results demonstrate that wing kinematics vary gradually as a function of flight speed, and that the patterns of variation are strongly influenced by external wing shape.     

Anatomy of the propatagium: The great horned owl (Bubo virginianus)

Skinfolds and feathers form the profile of the avian airfoil. The wing of birds has a nearly flat profile from shoulder to carpus, without the presence of the propatagium. The propatagium is the largest skinfold of the wing; it fills the angle formed by the partially flexed elbow, and with its feathers forms a rounded leading edge and dorsally cambered profile added to the cranial aspect of the wing. The propatagium is variably deployed, relative to elbow extension, in flight; support for its cambered shape is maintained by multilayered collagenous and elastic tissue networks suspended between leading edge and dorsal antebrachium. The leading edge ligament (Lig. propatagiale) courses from deltopectoral crest to carpus and, with its highly distensible center section, supports the leading edge of the propatagium across a range of wing extensions. The elbow extension limiting ligament (Lig. limitans cubiti) courses from deltopectoral crest to proximal antebrachium and limits maximum elbow extension. M. deltoideus, pars propatagialis inserts on the proximal end of the common origin of the propatagial ligaments and, by way of the insertions of the two ligaments, coordinates (1) automatic flexion / extension actions of the elbow and wrist, (2) propatagial deployment, and (3) tension along the length of Lig. propatagiale supporting the leading edge. © 1994 Wiley-Liss, Inc.     

Flow Visualization of Rhinoceros Beetle (Trypoxylus dichotomus) in Free Flight

Aerodynamic characteristics of the beetle,Trypoxylus dichotomus,which has a pair of elytra (forewings) and flexible hind wings,are investigated.Visualization experiments were conducted for various flight conditions of a beetle,Trypoxylus dichotomus:free,tethered,hovering,forward and climbing flights.Leading edge,trailing edge and tip vortices on both wings were observed clearly.The leading edge vortex was stable and remained on the top surface of the elytron for a wide interval during the downstroke of free forward flight.Hence,the elytron may have a considerable role in lift force generation of the beetle.In addition,we reveal a suction phenomenon between the gaps of the hind wing and the elytron in upstroke that may improve the positive lift force on the hind wing.We also found the reverse clap-fling mechanism of the T.dichotomus beetle in hovering flight.The hind wings touch together at the beginning of the upstroke.The vortex generation,shedding and interaction give a better understanding of the detailed aerodynamic mechanism of beetle flight.     

Hindlimb Motion during Steady Flight of the Lesser Dog-Faced Fruit Bat,Cynopterus brachyotis

In bats, the wing membrane is anchored not only to the body and forelimb, but also to the hindlimb. This attachment configuration gives bats the potential to modulate wing shape by moving the hindlimb, such as by joint movement at the hip or knee. Such movements could modulate lift, drag, or the pitching moment. In this study we address: 1) how the ankle translates through space during the wingbeat cycle; 2) whether amplitude of ankle motion is dependent upon flight speed; 3) how tension in the wing membrane pulls the ankle; and 4) whether wing membrane tension is responsible for driving ankle motion. We flew five individuals of the lesser dog-faced fruit bat, Cynopterus brachyotis (Family: Pteropodidae), in a wind tunnel and documented kinematics of the forelimb, hip, ankle, and trailing edge of the wing membrane. Based on kinematic analysis of hindlimb and forelimb movements, we found that: 1) during downstroke, the ankle moved ventrally and during upstroke the ankle moved dorsally; 2) there was considerable variation in amplitude of ankle motion, but amplitude did not correlate significantly with flight speed; 3) during downstroke, tension generated by the wing membrane acted to pull the ankle dorsally, and during upstroke, the wing membrane pulled laterally when taut and dorsally when relatively slack; and 4) wing membrane tension generally opposed dorsoventral ankle motion. We conclude that during forward flight in C. brachyotis, wing membrane tension does not power hindlimb motion; instead, we propose that hindlimb movements arise from muscle activity and/or inertial effects.     

Morphological variation associated with dispersal capacity in a tree‐killing bark beetle Dendroctonus ponderosae Hopkins

相似文献   

Support and deformability in insect wings

Coupled investigations of insect wing movements and detailed wing morphology are in progress, and some functional principles underlying wing design are emerging. High speed cine and still photography and stroboscopy indicate that most wings undergo orderly deformation in flight. Common patterns are described and their significance discussed in the light of recent aerodynamic studies.
Many aspects of wing morphology–venational features, relief, thickened areas, flexionlines and vein fractures–may be related to the control of three-dimensional shape while beating. It is usually possible to distinguish areas specialized for deformability, and for support and the limiting of deformation. Some structural adaptations for these roles are described and illustrated.     

Morphology of the elytral base sclerites

The elytral base sclerites (= sclerites located at the articular region between the forewing and thorax in Coleoptera) of selected taxa were examined and homologized. Although the elytral base sclerites are highly modified compared to the wing base sclerites of the other neopterans, they can be homologized by using the conservative wing flapping and folding lines as landmarks. A reduction of the first axillary sclerite was identified as a general trend of the elytral base sclerites, although the sclerite usually has a very important function to mediate flight power from the notum to the wing. This result indicates that the functional constraint against the basal sclerites is relaxed because of the lack of an ability to produce flight power by elytra. In contrast, the elytral folding system formed by the basal sclerites is well retained, which probably occurs because proper wing folding is a key for the shelter function of the elytra. The elytral base sclerites apparently contain more homoplasies than the serially homologous hindwing base sclerites of Coleoptera, which suggests that the structure is less useful for higher-level systematics. However, the faster evolutionary rate of the elytral base sclerites suggests there is potential for studying the lower-level phylogeny of Coleoptera.     

Do migrant birds have more pointed wings?: A comparative study

Summary Do birds that migrate over longer distances have more pointed wings than more sedentary birds? Within several bird genera, species differ considerably in their migration distances. This makes it possible to study the extent to which different taxa show similar morphological solutions to common selection pressures. I selected 14 species, two from each of seven passerine genera, to maximize within-genus differences in migration distance. Wing lengths and the lengths of eight primary feathers around the wing tip were measured to assess wing length and shape. Primary lengths were transformed to take into account the allometric relationship between the length of each feather and wing length and then collapsed into summary measures of shape by principal component analysis. I used the method of independent contrasts to address the effects of phylogeny. Wing length showed no relationship with migration distance. There was a correlation between migration distance and wing shape. It is concluded that long-distance migration has resulted in convergent morphological evolution of long distal and short proximal primaries, resulting in wing tips close to the leading edge of the wing.     

Determinants of wing-feather moult speed in songbirds

Wing morphology is known to strongly affect flight performance by affecting lift and drag during flight. Performance may consequently deteriorate during feather moult due to the creation of feather gaps in the wing. Since wing gap size may directly affect the extent of reduced flight capacity, rapid moult involving the creation of large feather gaps is expected to substantially impair flight compared with the small gaps induced by a slower moult. To examine the factors affecting wing-feather moult speed, we studied adults of nineteen resident or very short-distance migrant passerine species during their post-breeding moult using a model-selection framework following a phylogenetically controlled analysis. We examined the speed of wing-feather moult in relation to each species’ flight distance index that was estimated based on local foraging movements rather than on longer flights (e.g., migration), assessed by the Delphi technique of expert evaluation. Moult speed was also examined with respect to six morphometric variables: body mass, wing loading, the feather comprising the tip of the wing, aspect ratio, wing span, and wing area. Our results suggest that flight distance index is the most important factor determining the speed of wing-feather moult in songbirds. Species that regularly fly a shorter distance were found to moult quickly, and those that take relatively longer flights moult slowly. These results suggest that the aerodynamic cost of wing area reduction due to feather moult shapes the evolution of annual routine processes by dictating a slower moult speed (resulting in small wing gaps) for species that regularly fly long distances and consequently may be affected more substantially by large wing gaps compared with short distance flyers.