Differences In Wing Morphology Research Articles

Wake patterns of the wings and tail of hovering hummingbirds

The flow fields of slowly flying bats and faster-flying birds differ in that bats produce two vortex loops during each stroke, one per wing, and birds produce a single vortex loop per stroke. In addition, the circulation at stroke transition approaches zero in bats but remains strong in birds. It is unknown if these difference derive from fundamental differences in wing morphology or are a consequence of flight speed. Here, we present an analysis of the horizontal flow field underneath hovering Anna’s hummingbirds (Calypte anna) to describe the wake of a bird flying at zero forward velocity. We also consider how the hummingbird tail interacts with the wake generated by the wings. High-speed image recording and analysis from three orthogonal perspectives revealed that the wing tips reach peak velocities in the middle of each stroke and approach zero velocity at stroke transition. Hummingbirds use complex tail kinematic patterns ranging from in phase to antiphase cycling with respect to the wings, covering several phase shifted patterns. We employed particle image velocimetry to attain detailed horizontal flow measurements at three levels with respect to the tail: in the tail, at the tail tip, and just below the tail. The velocity patterns underneath the wings indicate that flow oscillates along the ventral–dorsal axis in response to the down- and up-strokes and that the sideways flows with respect to the bird are consistently from the lateral to medial. The region around the tail is dominated by axial flows in dorsal to ventral direction. We propose that these flows are generated by interaction between the wakes of the two wings at the end of the upstroke, and that the tail actively defects flows to generate moments that contribute to pitch stability. The flow fields images also revealed distinct vortex loops underneath each wing, which were generated during each stroke. From these data, we propose a model for the primary flow structures of hummingbirds that more strongly resembles the bat model. Thus, pairs of unconnected vortex loops may be shared features of different animals during hovering and slow forward flight.

Diet and prey selection in Mehelyi's horseshoe bat Rhinolophus mehelyi (Chiroptera, Rhinolophidae) in the south-western Iberian Peninsula

We studied diet and prey selection in Mehelyi's horseshoe bats Rhinolophus mehelyi in the south-western Iberian Peninsula, during the breeding seasons of 2003, 2006, and 2007. Faecal pellets were collected individually and arthropod fragments identified to family level, where possible. Arthropod availability was assessed using Malaise traps. Selection analyses were performed using Compositional Analysis and a Chi-square goodness-of-fit test. The bulk of the diet of R. mehelyi consisted of Lepidoptera, representing more than the 80% of the consumed volume on average (excluding juveniles), and more than 90% of the average percentage occurrence. This pattern was consistent across localities. Neuroptera and Tipulidae were locally abundant. Other important prey categories were Chrysomelidae, Brachycera, and Chironomidae. ANOVA tests showed that there were no significant differences between males and females in consumed prey categories, whereas juveniles consumed significantly less Lepidoptera than adults. Lepidoptera was the first prey category in the preference rank, followed by Myrmeleontidae, Chrysopidae and Tipulidae, and all of these were consumed more than expected by chance. This work shows that R. mehelyi is a moth specialist and suggests that juveniles may acquire this strategy while gaining hunting experience. Given the similarities in echolocation call characteristics and diet in the sibling R. mehelyi and R. euryale, they may compete for trophic resources in sympatry. Nevertheless, subtle differences in wing morphology between both species are probably large enough to permit spatial resource partitioning.

The aerodynamics of big ears in the brown long-eared bat Plecotus auritus

Wings are the most obvious adaptation bats have for powered flight and differences in wing morphology are known to correlate with flight behaviour. However, the function(s) of ancillary structures such as the ears and tail, which may also play an important role during flight, are less well understood. Here we constructed a simplified model of a bat body with ears based upon morphological measurements of a brown long-eared bat (Plecotus auritus) to examine the aerodynamic implications of flying with large ears. The forces and moments produced by the model were measured using a sensitive 6-component force and torque balance during wind tunnel testing. The large ears of the model bat produced positive lift as well as positive drag of the same order of magnitude. At small ears angles (0° to 10°), increasing the angle of the ears resulted in an increase of the lift-to-drag ratio. At higher ear angles (> 10°) separation of the flow occurred which caused a large decrease in the lift-to-drag ratio produced. To maximise the benefit from the ears (i.e., lift-to-drag ratio) our model predicts that a horizontal free flying P. auritus should hold its ears at an approximate angle of 10°. The results of the pitching moment coefficient are inconclusive in determining if the large ears are important as flight control structures. The additional drag produced by the ears has consequences for the foraging behaviour of P. auritus with reductions in its flight speed and foraging range.

Variation in the Wing Morphology of Western Sandpipers (Calidris Mauri) in Relation to Sex, Age Class, and Annual Cycle

AbstractWe analyzed differences in wing morphology between sexes and among age classes of Western Sandpipers (Calidris mauri) to assess possible relationships with differential migration, acrobatic aerial displays, and potential vulnerability to predation, using size-constrained component analysis. Data on wing morphology of all four sex and age classes were available from birds spending the nonbreeding season in northwestern Mexico, and data on females were available from throughout the annual cycle. During the nonbreeding season, females had longer and more pointed wings than males. Within each sex, adults had longer and more pointed wings than immature birds. Throughout the annual cycle, adult females tended to have longer and more pointed wings than immature females. The longer and more pointed wings of females are consistent with selection on flight efficiency for longer migration distances. The shorter and rounder wings of males are consistent with stronger selection for agility in flight during acrobatic aerial displays, but also with weaker selection for flight efficiency because of shorter migration distances. The rounder wings of immature birds are most consistent with stronger selection for take-off performance as an antipredator adaptation, at a cost of lower flight efficiency during long-distance migratory flight. Considering intraspecific sex and age class differences in wing morphology of species with differential migration complements interspecific comparisons assessing the relative importance of selective agents acting on this character.Variación en la Morfología del ala de Calidris mauri con Relación al Sexo, la Edad y el Ciclo Anual

Morphological and Ecological Correlates of Coexistence in Malaysian Fruit Bats (Chiroptera: Pteropodidae)

Niche theory predicts that coexisting species should differ ecologically, morphologically, or behaviorally in ways that minimize competition. We used an ecomorphological approach to determine how coexisting species in the Old World fruit bat genus, Cynopterus, assort in morphological and ecological space. The study was conducted in peninsular Malaysia where 4 species of Cynopterus are broadly sympatric. Interspecific separation in resource use was estimated along 3 main axes: habitat, based on abundance across a habitat gradient at 2 sites; trophic niche, inferred from a suite of cranial and postcranial characters; and locomotory behavior and efficiency, inferred from wing morphology. Habitat associations, overall size, and the size and shape of the trophic apparatus were all important in separating 2 or more species, whereas interspecific differences in wing morphology were minor. In combination, the results of this study suggest that relatively minor separation among Cynopterus species pairs along single axes of resource use is sufficient to counteract overlap on other axes, and permit the coexistence of potential competitors.

Phenotypic variation among local populations of phlebotomine sand flies (Diptera: Psychodidae) in southern Turkey

The wing-shape morphology of local populations of the medically important phlebotomine sand flies, Phlebotomus sergenti, P. papatasi, P. tobbi, and P. similis, were examined in both sexes by using geometric morphometrics. There are three major mountain ranges that may serve as geographical barriers for species distribution in the study area and four main gaps were recognized among these barriers. We found no statistically important differences in wing morphology in all examined species in both sexes for all local populations. These results show that the barriers are not sufficient to stop gene flow among local populations of sand flies. The graphical depiction of PCA, CVA, and F-test confirmed our morphometric study suggesting that the difference in wing morphology between P. similis and P. sergenti indicates that these are clearly different species. These two show sympatric distribution in the Konya Plain of Anatolia.

VARIATION IN THE WING MORPHOLOGY OF WESTERN SANDPIPERS (CALIDRIS MAURI) IN RELATION TO SEX, AGE CLASS, AND ANNUAL CYCLE

Abstract We analyzed differences in wing morphology between sexes and among age classes of Western Sandpipers (Calidris mauri) to assess possible relationships with differential migration, acrobatic aerial displays, and potential vulnerability to predation, using size-constrained component analysis. Data on wing morphology of all four sex and age classes were available from birds spending the nonbreeding season in northwestern Mexico, and data on females were available from throughout the annual cycle. During the nonbreeding season, females had longer and more pointed wings than males. Within each sex, adults had longer and more pointed wings than immature birds. Throughout the annual cycle, adult females tended to have longer and more pointed wings than immature females. The longer and more pointed wings of females are consistent with selection on flight efficiency for longer migration distances. The shorter and rounder wings of males are consistent with stronger selection for agility in flight during ac...

Relationships between body size, wing morphology, and perch height selection in a guild of Libellulidae species (Odonata)

Abstract Ten common libellulid species perch along the shoreline of lakes and ponds in South Carolina, USA. We collected individuals at five ponds throughout summer 2005, weighed them in the field, and calculated wing loading (N·m2) and wing aspect ratios from digital photographs. We measured the perch-height preferences of these species in ‘low perch’ (10, 20, 30, and 40 cm) and ‘high perch’ (20, 40, 60 and 80 cm) experiments. Flywheel anemometers recorded wind speeds at each perch height. Species differed significantly in mean body mass, spanning nearly an order of magnitude from Perithemis tenera (67 mg) to Libellula vibrans (633 mg). There were also significant differences in wing morphology that correlated with mean mass; larger species had greater wing loadings and greater wing aspect ratios that smaller species. Species also differed significantly in their perch-height prereferences in both experiments, in a manner correlating with body mass and hindwing aspect ratios. Erythemis simplicicollis and ...

The effect of age and sex on wing morphology and body size of the Bearded Tit Panurus biarmicus in relation to complete moult

In sedentary birds, variation in wing morphology as a result of complete moult during the transition from juvenile to adult plumage is poorly understood. The aim of this study was to characterise sex‐ and age‐related differences in wing morphology resulting from a complete post‐juvenile moult in an isolated, sedentary population of the Bearded Tit Panurus biarmicus at El Hondo Natural Park reedbeds (SE Spain). Variation in wing morphology was evaluated by means of a Size‐Constrained Components Analysis (SCCA) of standardised primary lengths of 66 birds trapped for ringing. Wing traits representing size and shape showed differences among age and sex classes, adults having significantly greater wing sizes than juveniles and males less rounded or convex wings than females. Structural body size also varied significantly among sex classes, females being smaller than males. Sex‐ and age‐specific differences in wing morphology of these Bearded Tits may represent adaptations to the sedentary and colonial behaviour of the local population within constraints imposed by a reedbed microhabitat.

Habitat structure, wing morphology, and the vertical stratification of Malaysian fruit bats (Megachiroptera: Pteropodidae)

This study investigated the vertical stratification of Old World fruit bats (Chiroptera: Pteropodidae) in relation to habitat structure and wing morphology, in a lowland Malaysian rain forest. In total, 352 fruit bats of eight species were captured within the subcanopy of the structurally complex old-growth forest during 72 306 m2 mist net hours of sampling. Fruit bat species that were grouped in relation to capture height were also grouped in relation to wing morphology – with those species predicted to have more manoeuvrable flight (i.e. lower wing-loadings and lower aspect-ratios) captured in increasingly cluttered airspaces. Thus, small differences in wing morphology are likely to be ecologically significant to the vertical stratification of bats. Hence, habitat heterogeneity may be a key factor promoting fruit bat species diversity in old-growth palaeotropical forests.

Identity and phylogenetic status of two sibling gall midge species (Diptera: Cecidomyiidae: Contarinia) on the perennial herb Vincetoxicum hirundinaria

Abstract Contarinia comprises one of the largest genera among gall forming midges of Cecidomyiidae, where identification and species relationships are uncertain. Using data on phenological development, morphometric relationships and mitochondrial DNA, the status of two isomorphic species, C. vincetoxici and C. asclepiadis, which attack the perennial herb Vincetoxicum hirundinaria, were investigated. Data show that they are two distinct species. In rearing experiments, the two gall midges were shown to have different times of adult emergence. Small differences in wing morphology were revealed that separate the two species from each other, as well as from C. loti, the type species of Contarinia. Sequence differences in the mitochondrial cytochrome b gene corroborate the specific status of C. vincetoxici and C. asclepiadis. Furthermore, a phylogenetic analysis, also including three other Contarinia species, showed that the two gall midges on V. hirundinaria are not even the most closely related species, suggesting two separate evolutionary colonizations of the host plant.

Wing Ecomorphology of Seabirds from Johnston Atoll

Wing morphology of nine species of seabirds from Johnston Atoll in the central tropical Pacific was analyzed to determine how wing size and shape correlated with observed foraging behavior and, in some species, the energetic cost of flight. Red-tailed Tropicbirds (Phaethon rubricauda) and Christmas Shearwaters (Puffinus nativitatis) had lower wing areas, shorter wing spans, and higher relative wing loading than would be predicted from mass alone. Brown Noddies (Anous stolidus) and Red-footed Boobies (Sula sula) had lower wing loading, Brown Boobics (Sula leucogaster) and Sooty Terns (Sterna fuscata) had higher aspect ratios, and Brown Noddies had lower aspect ratio than would be predicted from mass alone. Aspect ratio showed greater intraspecific variation than the other variables. In most cases, predicted differences in wing morphology correlated well with observed foraging differences among species, and species that did not differ significantly in body mass differed with respect to wing size and shape; these morphological differences reflected varying flight and foraging behaviors. Sooty Terns had a higher aspect ratio and higher wing loading than Brown Noddies reflecting their more pelagic lifestyle, and Christmas Shearwaters had a lower aspect ratio and higher wing loading than Wedge-tailed Shear-waters (Puffinus pacificus) reflecting their pursuit plunging behavior.

Geographic variation of wing morphology in three Eurasian populations of the fruit fly, Drosophila lummei

Differences in wing morphology are described for three Eurasian populations of Drosophila lummei. A truss network of wing characters was used to quantify wing size and shape for 149 individuals from Japan, Sweden and Russia. Sexual dimorphism in wing size and shape was not substantial, so the sexes were pooled and multivariate analyses conducted. Both principal components analysis and discriminant analysis of wing morphology revealed significant differences among all geographic groups. These differences indicate that morphometric analysis of wing characters can reliably discriminate between geographic groups and accurately classify individuals of the three Drosophila lummei populations. Principal components analysis also revealed that characters occurring in the same section of the wing formed correlated suites which corresponded to morphologically and functionally distinct areas of the wing. This study is unique because it detects subtle morphological differences within a single species of fruit fly across an intercontinental distribution.The results corroborate genetic studies in which geographic variation was found for inversion polymorphisms among spatially separated populations of Drosophila lummei.