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Forward-swept wings were researched and introduced to improve maneuverability, control, and fuel efficiency while reducing drag and they are often used alongside canards, to further enhance their characteristics. In this research, the effects of canard dihedral angles on the wing loading of a forward-swept wing in transonic flow conditions were studied, as the wing loading provides a measure of wing's efficiency (lift/drag). A generic aircraft model from literatures was selected, simulated, and compared to, using CFD software ANSYS/Fluent where the flow equations were solved to calculate the aerodynamic characteristics. The research was carried at two different Mach numbers, 0.6 and 0.9, for five different canard dihedral angles which traverses from below the wing plane to above it, at various flow angles of attack. It was concluded that as the dihedral angle increased, lift increases for the same angle of attack for Mach 0.6 and 0.9 which increases the efficiency of the wing. The wing span loading occur at 10° dihedral angle for both Mach speeds, while, at 10° anhedral, the lift was minimal due to leading-edge flow separation on the FSW's lower surface. Thus, it is concluded that the canard at positive dihedral angles ensures increased wing span loading efficiency. [ABSTRACT FROM AUTHOR]

Scarcity of morphological data limits the potential of functional ecology approaches, which rely on traits to elucidate ecological processes. Dragonflies and damselflies (Odonata) are a frequently used ecological model for which, however, only limited morphological data is available. Here, it is presented a field sampling protocol to collect ecologically relevant yet largely unavailable morphological traits of Odonata. The protocol enables the straightforward collection of traits from living individuals directly in the field. Those traits include body mass, wing area and wing loading as well as thorax width, hindwing length and body length. Furthermore, the protocol allows for posterior wing morphometric analyses. The protocol proved to be robust and universally applicable based on testing on roughly half (76) of all European odonate species. The use of this protocol can increase our understanding of odonatan morphology at interspecific and intraspecific levels and assist in developing mechanistic understanding of their ecology. [ABSTRACT FROM AUTHOR]

Insect flight is a complex trait involved in different behaviors, from the search for sexual partners, food, or breeding sites. Many studies have postulated the adaptive advantages of certain morphological traits in relation to increased flight capacity, such as low values of wing loading or high values of wing:thorax ratio and wing–aspect ratio. However, few studies have evaluated the relationship between variables related to flight and morphological traits in Drosophila. This work aimed to study morphological traits in males and females of two pairs of sibling species: Drosophila buzzatii Patterson and Wheeler‐Drosophila koeferae Fontdevila and Wasserman, and Drosophila melanogaster Meigen‐Drosophila simulans Sturtevant, and to analyze its relationship with flight. We detected the highest proportion of flight time in D. koepferae and D. simulans compared to D. buzzatii and D. melanogaster, respectively. Our results also revealed sexual dimorphism, with males exhibiting a higher proportion of flight time than females. Surprisingly, we did not find a general pattern to explain the relationship between morphology and the proportion of flight time because associations varied depending upon the analyses (considering all groups together or each sex‐species combination separately). Moreover, these associations explained a low percentage of variation, suggesting that other nonmorphological components related to flight, such as physiological variables, should be taken into account. This work allowed us to show the variability and complexity of an aspect of flight, suggesting that the adaptive role of the morphological traits studied might have been overestimated. [ABSTRACT FROM AUTHOR]

Simple Summary: We studied the flight dispersal of two congeneric beetle species (Ochthebius quadricollis and Ochthebius lejolisii) living in Mediterranean coastal rockpools; temporary and fragmented habitats with extreme environmental conditions (high salinity, high temperature, and strong desiccation). We used a multi-approach (experimental flying assays, wing morphology, and genetic markers) to measure flight capacity. We found that both species had similar flight behaviour, with most individuals flying when water was heated. Females had larger body sizes and wing areas and lower wing loading than males, which suggested higher dispersal capacity. The wing shape of both species was also shown to be an efficient adaptation to flight. However, the molecular data point to passive dispersal assisted by wind at small-to-medium spatial scales (<100 km). Flight dispersal is ecologically relevant for the survival of supratidal rockpool insects. Dispersal has important consequences for colonisation, gene flow, and evolutionary divergence. Here, we compared the flight dispersal capacity of two congeneric beetle species (Ochthebius quadricollis and Ochthebius lejolisii) that exclusively inhabit these temporary, fragmented, and extreme habitats. We estimated flight capacity and inferred dispersal in both species using different approaches: experimental flying assays, examination of wing morphology, and comparison of microsatellite markers between species. Our findings revealed that both species exhibited similar flight behaviour, with 60 to 80% of the individuals flying under water heating conditions. Notably, females of both species had larger body sizes and wing areas, along with lower wing loading, than males in O. quadricollis. These morphological traits are related to higher dispersal capacity and more energetically efficient flight, which could indicate a female-biassed dispersal pattern. The wing shapes of both species are characterised by relatively larger and narrower wings in relation to other species of the genus, suggesting high flight capacity at short distances. Molecular data revealed in both species low genetic divergences between neighbouring populations, non-significant differences between species, and no isolation by distance effect at the study scale (<100 km). These results point to passive dispersal assisted by wind. [ABSTRACT FROM AUTHOR]

Wings in birds vary tremendously in size and shape across species. Ecological needs are thought to shape variation across species in wing morphology over evolutionary times. For instance, demands for energetic efficiency in species that fly long distances have produced long and narrow wings with a high aspect ratio. Demand for maneuverability in cluttered habitats or to escape predators more easily have favored wings with large areas relative to body size producing a low wing loading. The association between ecological needs and wing morphology is complex, however, and could involve other ecological variables. Here, I draw attention to two ecological factors that have received little attention, namely, life history and sociality. Species at the slow end of the life history continuum emphasize adult survival over reproduction and are considered risk averse. I predicted that such species would benefit from low wing loading and low aspect ratio to increase maneuverability and the ability to escape predators. More solitary species cannot rely on others in their groups to decrease predation risk. I predicted that such species should also benefit from low wing loading and low aspect ratio. Using data from the literature on wing loading and aspect ratio in a large number of species, I examined these predictions in a phylogenetic framework including several potentially confounding ecological variables that have been previously linked to wing morphology such as habitat, lifestyle, and migration. As predicted, more solitary species tended to have low wing loading and low aspect ratio. Low wing loading was also more common in species at the slow end of the life history continuum, but aspect ratio was higher than predicted. Overall, the results support the idea that life history and sociality can predict variation across species in wing morphology and highlight the effect of predation risk on the evolution of wing morphology in birds. [ABSTRACT FROM AUTHOR]

Wing morphology is an important indicator of the foraging ecology of bats, as they may constrain the foraging habitats bat can use, the types of food items that they can detect, and how those resources are perceived. The fruit eating bats differ from insect eating bats in their foraging patterns. Low aspect ratio, short wingspan and high wing loading in respect to that of the body size has provided them with commuting foraging flights covering wider area. Three of the megachiropterans species of the present study shown remarkable variation in their flight patterns depending on their wing morphology. But all of them show broad wing with high wing loading enabling them to attain a moderate flight speed which provide them sufficient foraging time and long-distance commuting flight. But they show variation in their wingspan, aspect ratio and wing tip length and wing tip shape. This variation helps each one of them to attain species-specific manoevrability flight in cluttered area, low cost of transport and agility. This variation in turn reflects their foraging pattern and selection of food items. The present study has made an attempt to focus on the variation in the wing morphology of three forest fruit and correlated with foraging strategy. [ABSTRACT FROM AUTHOR]

Active gust load alleviation techniques exhibit a high potential in significantly reducing the transient gust loads on aircraft. In this work the aerodynamic potential of trailing-edge flaps and leading-edge flaps is numerically studied with the purpose to significantly reduce the structural gust loads. The utilized spanwise-segmented flaps represent slight modifications of existing devices for high-lift and maneuvering. The investigations based on unsteady Reynolds-averaged Navier-Stokes computations are conducted by employing a generic wing-fuselage aircraft configuration at transonic flow conditions. Idealized discrete "1-cos "-type vertical gusts that are relevant for the certification process are used as representative atmospheric disturbances. The focus of this paper is to introduce a practicable prediction method for required trailing- and leading-edge flap deflections for a significant mitigation of gust-induced wing loads. The three-dimensional flap deflections are determined by parametric two-dimensional simulations at representative wing sections. Different extensions of the estimation approach are investigated to assess the influence of the wing planform, the finite wing span, the aerodynamic phase lags, and the flap scheduling. It is shown that the trailing- and leading-edge flaps are promising in terms of alleviation of gust-induced wing bending and wing torsional moments, respectively. However, at high leading-edge flap deflections that are necessary for a full compensation of the wing torsional moment large-scale flow separation is identified. The introduced gust load alleviation approach indicates a good transferability between two-dimensional airfoil and three-dimensional wing aerodynamics for unsteady flap deflections. [ABSTRACT FROM AUTHOR]

We describe the first known case of disproportionate dwarfism in bats. The specimen is an adult male Seba's short-tailed bat, Carollia perspicillata (Linnaeus, 1758), captured in a ground-level mist net during a survey in a lowland Atlantic Forest area in southeastern Brazil. Examination of the specimen skull showed craniofacial anomalies, including microdontia in the upper incisors, oligodontia in the third upper molars, fusion of the nasal septum and the left ventral nasal concha, and a narrower foramen magnum. Post-cranial changes were mainly related to shortened radius, tibia, and metacarpals, compared to the reference sample in multivariate space. Given its unusual morphology with short wings and average body mass, the dwarf would have higher wing loading, fly faster, require more power to fly, and have a shorter flight range compared to the species pattern. Because it presented good body condition and reached adulthood, possible mechanisms of functional compensation are discussed. [ABSTRACT FROM AUTHOR]

Mobility in flying animals can be assessed by variations in morpho–ecological traits such as body, thorax and wing sizes, wing shape and the proportion between body mass and wing area. Habitat loss and fragmentation can promote phenotypic plasticity and microevolutionary divergencies in natural populations. In this context, sexual differences in physiology and behaviour can impose different selection pressure on morphological aspects related to flight.We evaluated the relative impact of forest patch area and habitat amount in shaping flight‐related morpho–ecological traits of the tropical butterfly Hamadryas februa. We find a marked sexual dimorphism in the species, with females being larger, having larger thorax, higher wing loadings and larger wing total area than males. These trait values indicate females as the more dispersive sex. We show that habitat amount modulates body mass allocations in both sexes, leading to an increase in thorax mass with decreasing habitat amount. The effect of habitat amount was more pronounced in females, which increased total mass and wing loading while decreasing thorax allocation with decreasing habitat amount. This outcome suggests that females increase abdominal mass in response to a reduction in habitat amount. The focal forest patch increasing area was linked to increases in hindwing lengths in both females and males.We advocate that both landscape metrics (i.e., habitat amount and patch area) should be considered in studies evaluating landscapes' impacts on insect mobility. We discuss results in terms of the species' sexual differences in flight behaviour and the relative importance of both landscape metrics. [ABSTRACT FROM AUTHOR]

Abstract Background Flight performance and dispersal behaviour can differ between sexes, resulting in sex-biased dispersal. The primary sex ratio of populations may also explain dispersal bias between sexes, as this bias may evolve with the primary sex ratio to reduce intrasexual competition. Although dispersal bias between sexes is relevant to population dynamics, there are few studies on sex-biased dispersal in insects. We studied the flight performance and dispersal behaviour of seven saproxylic beetle species associated with tree hollows from a sex perspective. We also analysed the possible coevolution of flight performance with the primary sex ratio. Methods Wing loading and wing aspect ratio were used as measures of the flight performance of species and sexes. Dispersal behaviour was explored by analysing the frequency of each sex in interception traps versus the primary sex ratio obtained by tree hollow emergence traps using contingency tables and posthoc standardized residuals. A more active flight behaviour was expected for the sex with higher capture frequency in the interception traps. To explore the causes of flight performance bias between sexes, we searched for possible correlations between wing loading or wing aspect ratio and primary sex ratio using Pearson’s correlation coefficient. Results Wing loading and wing aspect ratio differed between species and sexes, with flight performance being higher in males than in females for four of the seven species analysed. Dispersal behaviour and flight performance matched in the case of Elater ferrugineus; males showed higher flight performance and were the most collected sex in the interception traps (more active flyers). In contrast, the higher flight activity of Cetonia carthami aurataeformis females was not correlated with a higher flight performance than that of males. Moreover, we found that a bias in the primary sex ratio towards females is often correlated with a decrease in female flight performance. Conclusions We stress that flight performance and dispersal behaviour of sexes do not always go hand in hand. Moreover, the relationship between the sex ratio and flight performance bias between sexes is not driven by competition within the most abundant sex. The inclusion of a sex perspective in insect dispersal studies would be useful to detect dispersal bias between sexes and its causes and would allow for further analysis of its effects on population dynamics.

A multitude of hymenopteran species exhibit sexual dimorphism for simple traits, such as color, size, or antennal segment number. These differences can reflect selection for specialized biological roles, many of which have not been documented for the majority of bee and wasp species. The excess power index (EPI) is an estimate of insect flight performance that is inferred by the combination of several morphological characteristics. We compared the female and male EPIs in four species of native bees: Agapostemon virescens Fabricius, Andrena carlini Cockerell, Melissodes bimaculata Lepeletier and Xylocopa virginica L.. While females of each species had a significantly larger whole body mass, males had a significantly larger EPI. A larger body mass for females is associated with egg laying abilities and foraging behavior. Male fitness may be dependent on EPI; males that have greater flight capacity can travel further or remain in flight for longer time periods in search of mates. [ABSTRACT FROM AUTHOR]

The eastern population of the North American monarch butterfly (Danaus plexippus) overwinters from November through March in the high-altitude (3000 m+) forests of central Mexico during which time they rely largely on stored lipids. These are acquired during larval development and the conversion of sugars from floral nectar by adults. We sampled fall migrant monarchs from southern Canada through the migratory route to two overwintering sites in 2019 (n = 10 locations), 2020 (n = 8 locations) and 2021 (n = 7 locations). Moderate to extreme droughts along the migratory route were expected to result in low lipid levels in overwintering monarchs but our analysis of lipid levels of monarchs collected at overwintering sites indicated that in all years most had high levels of lipids prior to winter. Clearly, a significant proportion of lipids were consistently acquired in Mexico during the last portion of the migration. Drought conditions in Oklahoma, Texas and northern Mexico in 2019 resulted in the lowest levels of lipid mass and wing loading observed in that year but with higher levels at locations southward in Mexico to the overwintering sites. Compared with 2019, lipid levels increased during the 2020 and 2021 fall migrations but were again higher during the Mexican portion of the migration than for Oklahoma and Texas samples, emphasizing a recovery of lipids as monarchs advanced toward the overwintering locations. In all 3 years, body water was highest during the Canada—USA phase of migration but then declined during the nectar foraging phase in Mexico before recovering again at the overwintering sites. The increase in mass and lipids from those in Texas to the overwintering sites in Mexico indicates that nectar availability in Mexico can compensate for poor conditions experienced further north. Our work emphasizes the need to maintain the floral and therefore nectar resources that fuel both the migration and storage of lipids throughout the entire migratory route. [ABSTRACT FROM AUTHOR]

Key message: Wing loading, diaspore type (round-winged vs. single-winged), and aerodynamic motion (autogyro vs. floater) influence the terminal velocity of wind-dispersed diaspores and falling patterns. The dispersal ability of diaspores dispersed by wind can be reflected in the terminal velocity of the diaspore. Therefore, we measured the terminal velocity of wind-dispersed diaspores in 17 major forest and urban tree species in South Korea and tracked falling diaspore patterns up to the achievement of terminal velocity using the video camera recording method. In addition, the morphological characteristics of the diaspores were measured, and their effect on diaspore terminal velocity tested. Chamaecyparis obtusa (2.66 m s−1) had the highest terminal velocity, whereas Picea abies (0.61 m s−1) had the lowest terminal velocity. Falling diaspores achieved terminal velocity through (1) the oscillating falling pattern of floater diaspores, with a constant descent velocity with minor increases and decreases; (2) the decelerating falling pattern of single-winged diaspores, with accelerating descent velocity followed by rapid deceleration to terminal velocity; or (3) the accelerating falling pattern of round-winged autogyro diaspores, with descent velocity increasing steadily up to terminal velocity. The terminal velocities of single-winged diaspores were significantly lower than those of round-winged diaspores. Although there were cases of similar terminal velocity between species in the same genera (e.g., Abies, Pinus), there were large intraspecific differences in terminal velocity within the same genus due to morphological differences (e.g., Acer). The measured terminal velocities could be applied in simulations for diaspore dispersal distances for forestry tree species. The present study explored the relationship between diaspore morphological characteristics and terminal velocity, and is the first to report the dispersal ability of wind-dispersed seeds of major tree species in East Asia. The findings of the present study can be adopted as key input variables in seed dispersal modeling and facilitate the establishment of natural regeneration plans and conservation of endangered species in the wake of climate change. [ABSTRACT FROM AUTHOR]

Simple Summary: Morphology and function depend on the ecological niche in which an animal lives. Barn owls, occurring on all continents, occupy a nocturnal niche. These birds prey mainly on small rodents but include other small vertebrates and invertebrates in the diet. The size of the barn-owl species and subspecies varies considerably. The American continent harbors the species Tyto furcata. The body mass of the subspecies in North America (T.f.pratincola) is about a factor of two higher than that of the subspecies living on the Galapagos archipelago (T.f.puncatissima). We asked how this difference translates into aerodynamic parameters. The key question was whether there is so-called similarity scaling or not. In other words, whether important aerodynamic parameters scale according to body mass. This is called isometric scaling. Deviation from isometric scaling is called allometric scaling. If we use the subspecies from the continent as a reference, we find that the Galapagos barn owl has relatively larger wings than expected from isometric scaling. This translates into a lower wing loading in punctatissima than in pratincola. A lower wing loading means higher maneuverability. We speculate that the higher maneuverability allows the Galapagos owl to catch smaller prey, especially insects. Aerodynamic parameters, such as wing loading, are important indicators of flight maneuverability. We studied two subspecies of the American Barn owl (Tyto furcata), the North American subspecies, T.f.pratincola, and the Galapagos subspecies, T.f.punctatissima, with respect to aerodynamic parameters and compared our findings with those in other owl and bird species. The body mass of T.f.pratincola is about two times higher than that of T.f.punctatissima. Wing loading between the two subspecies scales allometrically. Wing loading in T.f.pratincola is about 50% higher than in T.f.punctatissima. The scaling of wing length is not statistically different from the prediction for isometric scaling. By contrast, the wing chord in T.f.punctatissima is larger than predicted by isometric scaling, as is the wing area. The scaling of wing loading observed here for T.f.punctatissima differs considerably from the scaling in other owl and bird species as available in the literature. We speculate that the allometric scaling helps T.f.punctatissima to catch smaller prey such, as insects that are found in many pellets of T.f.punctatissima, despite the fact that in both subspecies, small rodents make up most of the diet. [ABSTRACT FROM AUTHOR]

Background: Flight performance and dispersal behaviour can differ between sexes, resulting in sex-biased dispersal. The primary sex ratio of populations may also explain dispersal bias between sexes, as this bias may evolve with the primary sex ratio to reduce intrasexual competition. Although dispersal bias between sexes is relevant to population dynamics, there are few studies on sex-biased dispersal in insects. We studied the flight performance and dispersal behaviour of seven saproxylic beetle species associated with tree hollows from a sex perspective. We also analysed the possible coevolution of flight performance with the primary sex ratio. Methods: Wing loading and wing aspect ratio were used as measures of the flight performance of species and sexes. Dispersal behaviour was explored by analysing the frequency of each sex in interception traps versus the primary sex ratio obtained by tree hollow emergence traps using contingency tables and posthoc standardized residuals. A more active flight behaviour was expected for the sex with higher capture frequency in the interception traps. To explore the causes of flight performance bias between sexes, we searched for possible correlations between wing loading or wing aspect ratio and primary sex ratio using Pearson's correlation coefficient. Results: Wing loading and wing aspect ratio differed between species and sexes, with flight performance being higher in males than in females for four of the seven species analysed. Dispersal behaviour and flight performance matched in the case of Elater ferrugineus; males showed higher flight performance and were the most collected sex in the interception traps (more active flyers). In contrast, the higher flight activity of Cetonia carthami aurataeformis females was not correlated with a higher flight performance than that of males. Moreover, we found that a bias in the primary sex ratio towards females is often correlated with a decrease in female flight performance. Conclusions: We stress that flight performance and dispersal behaviour of sexes do not always go hand in hand. Moreover, the relationship between the sex ratio and flight performance bias between sexes is not driven by competition within the most abundant sex. The inclusion of a sex perspective in insect dispersal studies would be useful to detect dispersal bias between sexes and its causes and would allow for further analysis of its effects on population dynamics. [ABSTRACT FROM AUTHOR]

We report the first prey species consumed by the free-ranging Van Gelder's bat Bauerus dubiaquercus. We trapped four pregnant individuals of this species carrying freshly captured dung beetles. We describe the wing morphology and flight descriptors (wing loading and wing aspect ratio) of the species, which presents wings more suitable for capturing insects by aerial hawking, although the evidence suggests that is able to capture dung beetles of nearly 10% of its body mass in flight close to the ground. The species could obtain their prey while foraging on uncluttered pasture near forest edges. [ABSTRACT FROM AUTHOR]

Species' life‐history traits have a wide variety of applications in ecological and conservation research, particularly when assessing threats. The development and growth of global species' trait databases are critical for improving trait‐based analyses; however, it is vital to understand the gaps and biases in the available data.We reviewed bat wing morphology data, specifically mass, wingspan, wing area, wing loading, and aspect ratio, to identify issues with data reporting and ambiguity. Additionally, we aimed to assess taxonomic and geographic biases in trait data coverage.We found that most studies used similar field methodology, but that data reporting and quality were inconsistent/poor. Additionally, we noted several issues regarding semantic ambiguity in trait definitions, specifically around what constitutes wing area.Globally, we found that bat wing morphology trait coverage was low. Only six bat families had ≥40% trait coverage, and, of those, none consisted of more than 11 species in total. We found similar biases in trait coverage across International Union for Conservation of Nature Red List categories, with threatened species having lower coverage.Geographically, North America, Europe, and the Indomalayan regions exhibited higher overall trait coverage, while both the Afrotropical and Neotropical ecoregions showed poor trait coverage.The underlying biases and gaps in bat wing morphology data have implications for researchers conducting global trait‐based assessments. Implementing imputation techniques may address missing data, but only for smaller regional subsets with substantial trait coverage.Due to generally low overall trait coverage, increasing species' representation in the database should be prioritised. We suggest adopting an Ecological Trait Standard Vocabulary to reduce semantic ambiguity in bat wing morphology traits, to improve data compilation and clarity. Additionally, we advocate that researchers adopt an Open Science approach to facilitate the growth of a bat wing morphology trait database. [ABSTRACT FROM AUTHOR]

Flight behaviours of birds have been extensively studied from different angles such as their kinematics, aerodynamics and, more generally, their migration patterns. Nevertheless, much is still unknown about the daily foraging flight activity and behaviour of breeding birds, and potential differences among males and females. The recent development of miniaturized accelerometers allows us a glimpse into the daily life of a songbird. Here, we tagged 13 male and 13 female pied flycatchers (Ficedula hypoleuca) with accelerometers and used machine learning approaches to analyse their flight activity and effort during the chick rearing period. We found that during 2 h of foraging, chick-rearing pied flycatchers were flying on average 13.7% of the time. Almost all flights (>99%) were short flights lasting less than 10 s. Flight activity changed throughout the day and was highest in the morning and lowest in the early afternoon. Male pied flycatchers had lower wing loading than females, and in-flight accelerations were inversely correlated with wing loading. Despite this, we found no significant differences in flight duration and intensity between sexes. This suggests that males possess a higher potential flight performance, which they did not fully utilize during foraging flights., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

Active flow control has not found wide application in aircraft due to a combination of technical challenges, costs, and small impact on overall aircraft performance. Future applications, like alleviating dynamic loads, could be made possible through continuous improvement of flow control methods and increasingly restrictive environmental regulations. To date, few studies deal with active flow control for load alleviation on transport aircraft wings at high Reynolds and Mach numbers. A systematic assessment of flow control methods for load alleviation is therefore carried out. Multiple flow actuation schemes for gust load alleviation through dynamic lift reduction are investigated over a range of flight conditions using two-dimensional Reynolds-averaged Navier-Stokes simulations. Unsteady gust interactions with a clean airfoil produce target loads for load alleviation. Actuator performance is consequently evaluated based on an engineering model. The results show that select fluidic actuators outperform micro-mechanical actuators at low flight speeds and feature similar steady load response as trailing edge flaps for the entire flight envelope. The Coandă jet features relatively low mass flow requirements, but necessitates minimal dual-slot blowing for baseline performance recovery. The results of this study highlight the potential of fluidic flow control schemes for implementation into a dedicated gust load alleviation system. [ABSTRACT FROM AUTHOR]

The distances covered by migrant birds have been the subject of many studies. There are no estimates of the distances travelled by resident birds spending different amounts of time per day flying. Selection pressures similar to those due to migration are hypothesised to select for high aspect ratio wings, with low wing loading, among resident birds that spend a large amount of time per day flying. This reduces the energetic cost of flying and increases the birds' flight range. The estimated distances that aerial foraging birds fly per day (n = 4 species), and per year (n = 3 species) ranged from 83 to 215 km, and from 38,666 to 44,716 km, respectively. To test the abovementioned hypothesis, the phylogenetically controlled and mass-adjusted wingspan, mean wing chord, wing area, wing loading and wing aspect ratio of 77 resident passerine birds, that spend different amounts of time per day flying, were compared with those of 11 migrants. A decrease in wing loading and an increase in the aspect ratio of the birds' wings were significant predictors of an increase in the amount of time per day that the resident birds spent flying. No significant differences in the wing morphology traits between migrant, and resident birds that spend large amounts of time per day flying, were detected. The conclusion is that resident birds that spend a large amount of time per day flying have been subjected to the same selection pressures for energy-efficiency that have shaped aspects of the wing morphology traits of migrants. [ABSTRACT FROM AUTHOR]

Aim: An area threshold is usually considered as the point of abrupt change in the species–area relationship (SAR). Despite their widespread existence, few studies have considered the influence of data transformations on their presence or the mechanisms that generate them. The aims of this study were thus to test for the existence of an area threshold in butterfly assemblages and to compare trait–environment associations between small and large islands split by the threshold. Location: Zhoushan Archipelago, China. Taxon: Butterflies. Methods: We used the line‐transect method to survey butterflies on 42 islands from July to August 2014. We also collected data on three commonly used ecological traits of butterflies (wingspan, wing loading and body weight). We transformed the butterfly datasets into three types (log‐log, semi‐log and untransformed) and fitted each of them using a set of breakpoint regression models. We then split all islands into small and large islands based on the area threshold and analysed the trait–environment associations for each island group. Results: Two‐slope breakpoint models performed best for log‐log and semi‐log transformed datasets. However, the former exhibited a steep‐shallow shape with an area threshold of 0.820 km2 and the latter was in shallow‐steep shape with a threshold of 17.022 km2. By contrast, no threshold was detected when using the untransformed power model. Moreover, for small islands, small area and large isolation were positively correlated with species with large wing loading and body weight. For large islands, however, the perimeter to area ratio (PAR) was significantly and positively related to wing loading. Main conclusions: We found that data transformations may influence the detection of area thresholds. Trait–environment analyses can further provide novel and mechanistic insights into processes generating area thresholds. We urge that the influence of data transformations and ecological traits of species should be explicitly considered in future studies. [ABSTRACT FROM AUTHOR]

Venus has a harsh environment that makes its exploration especially difficult. Standard rovers like on Mars would not work as the intense temperature, and pressure would cause them to have a short operating time. At an altitude of about 55 km, Venus has an Earth-like atmosphere where a robotic system could survey for different features. A fixed-wing drone that can fly at this altitude would be practical. To obtain better information on Venus, the UAV can operate at lower altitudes until pressure and temperature operational limits are met. Then the drone can come back to an altitude of 55 km and alleviate until it is ready to go back into the lower altitudes. The atmospheric analysis is done to model Venus' characteristics at lower altitudes between 0 km and 60 km. Functions are made that model the atmospheric properties of Venus, such as temperature, pressure, density, and viscosity. These modeled atmospheric properties are then used to investigate the wing and thrust loading of a fixed-wing UAV in Venus. The results from this wing and thrust loading investigation are that, as wing loading and altitude increase, thrust loading also increases. This general trend is not consistent for all flight modes. For the case analyzed, thrust loading decreases between 0 N/m2 and 16 N/m2, and increases between 17 N/m2 and 80 N/m2 for flight at a constant altitude and cruise speed. There is a specific wing loading that requires the minimum thrust loading for each flight mode and altitude. For flight at a constant altitude and cruise speed, the best wing loading to have is about 16.75 N/m2. For flight at accelerated climb speed, the best wing loading to have is as low as it can be, in this case, it is 10 N/m2. This study gives outlines for future steps of designing fixed-wing UAVs for Venus exploration. • The atmospheric analysis is done to model Venus' characteristics at lower altitudes. • The feasibility of flying a fixed-wing drone in Venus is investigated. • Wing and thrust loading of a fixed-wing UAV in Venus atmosphere is studied. • Thrust loading decreases between 0 and 16 N/m2, and increases between 17 and 80 N/m2 in cruise. • Wing loadings that requires the minimum thrust loading for each flight mode and altitude are found. [ABSTRACT FROM AUTHOR]

The oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), is a pest of fruit and vegetable production that has become established in 42 countries in Africa after its first detection in 2003 in Kenya. It is likely that this rapid expansion is partly due to the reported strong capacity for flight by the pest. This study investigated the tethered flight performance of B. dorsalis over a range of constant temperatures in relation to sex and age. Tethered flight of unmated B. dorsalis aged 3, 10 and 21 days was recorded for 1 h using a computerized flight mill at temperatures of 12, 16, 20, 24, 28, 32 and 36 °C. Variations in fly morphology were observed as they aged. Body mass and wing loading increased with age, whereas wing length and wing area reduced as flies aged. Females had slightly larger wings than males but were not significantly heavier. The longest total distance flown by B. dorsalis in 1 h was 1559.58 m. Frequent short, fast flights were recorded at 12 and 36 °C, but long‐distance flight was optimal between 20 and 24 °C. Young flies tended to have shorter flight bouts than older flies, which was associated with them flying shorter distances. Heavier flies with greater wing loading flew further than lighter flies. Flight distances recorded on flight mills approximated those recorded in the field, and tethered flight patterns suggest a need to factor temperature into the interpretation of trap captures. [ABSTRACT FROM AUTHOR]

Chiroptera is the only group of mammals capable of powered flight. The mechanical basis of bat flight is well established, but evolution of its constituent aerodynamic variables remains poorly understood. Here, we determine the macroevolutionary patterns of traditional aerodynamic variables (wing loading, aspect ratio, tip shape index) in a comprehensive phylogeny of Chiroptera using an extensive dataset including key Eocene fossils. We optimized variables as continuous characters and fit models of character evolution to identify shifts in character optima. The reconstructed ancestral chiropteran morphotype presented low wing loading and low-to-intermediate aspect ratio, and remained unaltered for much of the first half of bat evolution (Paleogene). This evolutionary pattern may be explained by stabilizing selection responding to the strong constraints imposed by echolocation and flight on body size, and the physical constraints regarding aerodynamic efficiency acting on wing shape. Posterior specialization in some groups permitted divergence toward novel aerodynamic morphotypes in the second half of chiropteran evolutionary history (Neogene). We linked the most notable aerodynamic changes to ecological release from echolocation constraints (Pteropodidae), dietary-foraging shifts (Phyllostomidae, Noctilionidae), or advantage in face of environmental changes (Molossidae, Taphozoinae). The independently-evolved specialization of fast, enduring flight that allowed Molossidae and Taphozoinae (Emballonuridae) to perform aerial hawking of swarming insects in open spaces was linked to significant shifts in the optima of both wing loading and aspect ratio. These shifts were probably associated with the gradual spread of open-mosaic landscapes at a global scale since the Oligocene. [ABSTRACT FROM AUTHOR]

Flexibility in foraging behaviour is a key individual trait, promoting adaptive responses to changing environmental conditions. Such flexibility can be especially pronounced in marine predators that forage in highly dynamic environments and pursue ephemeral and patchily distributed prey. Individual characteristics, social interactions and resource availability may all promote behavioural flexibility, which in turn may foster divergence in foraging tactics within populations. The adoption of specific foraging tactics by individuals from the same population could be driven by a complex mixture of intrinsic and extrinsic factors. We GPS-tracked chick-rearing parents of a sexually size dimorphic, avian, marine top predator, the Scopoli's shearwater, Calonectris diomedea , across multiple foraging trips to investigate (1) intraindividual variation in foraging behaviour and (2) the effect of sex and wind conditions on the adoption of specific foraging tactics. Based on cluster analysis applied to GPS-derived behavioural patterns at the foraging trip scale, we identified variation in foraging trips, from fine- to coarse-scale foraging (FF and CF, respectively). FF trips were characterized by lower flight activity, shorter travel distances and more intensive prey-searching behaviour compared to CF trips. Individuals did not consistently perform FF or CF trips. Males were more prone to perform FF trips than females, but both sexes shifted towards CF trips with increasing wind intensity, probably to exploit the energetic advantages of dynamic soaring. We conclude that sex-specific foraging tactics reflect the interplay between sex-specific energetic optima, originating from differences in morphology and a reduction in the niche overlap between the sexes. By adopting flexible, sex-specific foraging tactics, shearwaters probably optimize their energy expenditure during the energy-demanding chick-rearing stage. Our study outlines the importance of both intrinsic and extrinsic factors in shaping interindividual variability in foraging behaviour. • Breeding shearwaters performed foraging trips with diverse food searching behaviour. • Trips were classified as mainly involving coarse-scale or fine-scale foraging. • Coarse-scale trips were mostly performed by females and with strong wind conditions. • Sex differences were likely related to sex differences in morphology. • Sex-specific foraging tactics could buffer intersexual competition for resources. [ABSTRACT FROM AUTHOR]

Lift-off velocity may be the most useful surrogate to measure the secondary dispersal capacity of diaspores. However, the most important diaspore attribute determining diaspore lift-off velocity is unclear. Furthermore, it is not known whether terminal velocity used to characterize the primary dispersal capacity of diaspores can also be used to predict their secondary wind dispersal capacity. Here, we investigate how diaspore attributes are related to lift-off velocity. Thirty-six species with diaspores differing in mass, shape index, projected area, wing loading, and terminal velocity were used in a wind tunnel to determine the relationship between diaspore attributes and lift-off velocity. We found that diaspore attributes largely explained the variation in lift-off velocity, and wing loading, not terminal velocity, was the best parameter for predicting lift-off velocity of diaspores during secondary wind dispersal. The relative importance of diaspore attributes in determining lift-off velocity was modified by both upwind and downwind slope directions and type of diaspore appendage. These findings allow us to predict diaspore dispersal behaviors using readily available diaspore functional attributes, and they indicate that wing loading is the best proxy for estimating the capacity for secondary dispersal by wind. [ABSTRACT FROM AUTHOR]

Reproduction in female spruce budworms, Choristoneura fumiferana , entails sedentary oviposition early in life (gravid females with their heavy abdomen full of eggs are unable to sustain flight), followed by short- and long-range dispersal by females that have laid a portion of their eggs. Body size measurements (wing surface area and dry weight) of gravid females, spent females at death (after all eggs are laid), and inflight females captured at light traps were collected at one location (forest stands near Fredericton in New Brunswick) over multiple years, from the outbreak stage (1976–1979: peak budworm abundance) to late declining phase with collapsing populations (1988–1989, following near two-fold magnitude of decline in adult density after 1987). For both demographic phases, females rarely flew until having laid at least 40% of their eggs, in contradiction to the hypothesis that females in defoliated forest stands can fly upon emergence due to their light-weight abdomen. As expected, the weight and fecundity of females in 1988–1989 was significantly lower than early on; in terms of body size (wing surface area), however, females were larger in late outbreak phase. These trends suggest that females have evolved morphological adaptation to further dispersal from deteriorated habitats. [ABSTRACT FROM AUTHOR]

Female mass in most altricial birds reaches its maximum during breeding at egg laying, which coincides temporally with the fertile phase when extra-pair paternity (EPP) is determined. Higher mass at laying may have two different effects on EPP intensity. On the one hand, it would lead to increased wing loading (body mass/wing area), which may impair flight efficiency and thereby reduce female's capacity to resist unwanted extra-pair male approaches (sexual conflict hypothesis). On the other hand, it would enhance female condition, favouring her capacity to evade mate guarding and to search for extra-pair mates (female choice hypothesis). In both cases, higher female mass at laying may lead to enhanced EPP. To test this prediction, we reduced nest building effort by adding a completely constructed nest in an experimental group of female pied flycatchers (Ficedula hypoleuca). Our treatment caused an increase in mass and thereby wing loading and this was translated into a significantly higher EPP in the manipulated group compared with the control group as expected. There was also a significant negative relationship between EPP and laying date and the extent of the white wing patch, an index of female dominance. More body reserves at laying mean not only a higher potential fecundity but a higher level of EPP as well. This interaction had not previously received due attention but should be considered in future studies of avian breeding strategies. Significance statement: While most research has been focused on determining possible criteria for extra-pair mate choice by females, less effort has been made on establishing if female traits are related to EPP and its intensity. One such trait is mass at laying which attains its highest level for breeding females of altricial birds. Our study indicates that a higher mass during the fertile phase not only has implications for female fecundity and predation risk but also for EPP in the resulting brood as more mass means a higher EPP. [ABSTRACT FROM AUTHOR]

Rising global temperatures force many species to shift their distribution ranges. However, whether or not (and how fast) such range shifts occur depends on species' dispersal capacities. In most ecological studies, dispersal‐related traits (such as the wing size or wing loading in insects) are treated as fixed, species‐specific characteristics, ignoring the important role of phenotypic plasticity during insect development.We tested the hypothesis that dispersal‐related traits themselves vary in dependence of ambient environmental conditions (temperature regimes, discharge patterns and biotic interactions during individual development).We collected data over 8 years from a natural population of the crane fly Tipula maxima in central Germany. Using linear mixed‐effect models, we analysed how phenotypic traits, phenological characteristics and population densities are affected by environmental conditions during the preceding 3, 6 and 12 months.We found a moderate (5.6%) increase in wing length per 1°C increase in mean annual temperatures during the previous year. At the same time, body weight increased by as much as 17.8% in females and 26.9% in males per 1°C, likely driven by increased habitat productivity, which resulted in a 16.4% (female) and 19.3% (male) increased wing loading. We further found a shorter, more synchronized emergence period (i.e. a narrower time frame for dispersal) with increasing temperatures.Altogether, our results suggest that dispersal abilities of T. maxima were negatively affected by elevated temperatures, and we discuss how similar patterns might affect the persistence of populations of other aquatic insects, especially stenoecious taxa with narrow distribution ranges. Our study calls for integration of information on temperature‐induced phenotypic plasticity of dispersal‐related traits into models forecasting range shifts in the face of climate change. Furthermore, the patterns reported here are likely to affect metapopulation dynamics of aquatic insects under climate change conditions and may contribute to the ongoing decline of insect biomass and diversity. [ABSTRACT FROM AUTHOR]

The body size of an animal is probably its most important functional trait. For arthropods, environmental drivers of body size variation are still poorly documented and understood, especially in tropical regions. We use a unique dataset for two species‐rich, phylogenetically independent moth taxa (Lepidoptera: Geometridae; Arctiinae), collected along an extensive tropical elevational gradient in Costa Rica, to investigate the correlates and possible causes of body‐size variation. We studied 15 047 specimens (794 species) of Geometridae and 4167 specimens (308 species) of Arctiinae to test the following hypotheses: 1) body size increases with decreasing ambient temperature, as predicted by the temperature–size rule; 2) body size increases with increasing rainfall and primary productivity, as predicted from considerations of starvation resistance; and 3) body size scales allometrically with wing area, as elevation increases, such that wing loading (the ratio of body size to wing area) decreases with increasing elevation to compensate for lower air density. To test these hypotheses, we examined forewing length as a proxy for body size in relation to ambient temperature, rainfall, vegetation index and elevation as explanatory variables in linear and polynomial spatial regression models. We analysed our data separately for males and females using two principal approaches: mean forewing length of species at each site, and mean forewing length of complete local assemblages, weighted by abundance. Body size consistently increased with elevation in both taxa, both approaches, both sexes, and also within species. Temperature was the best predictor for this pattern (–0.98 < r < –0.74), whereas body size was uncorrelated or weakly correlated with rainfall and enhanced vegetation index. Wing loading increased with elevation. Our results support the temperature–size rule as an important mechanism for body size variation in arthropods along tropical elevational gradients, whereas starvation resistance and optimization of flight mechanics seem to be of minor importance. [ABSTRACT FROM AUTHOR]

An important resource partitioning strategy allowing dung beetles to coexist in the same habitat, while utilising the same food, is species' separation of activity times. After establishing the diel activity period of three closely related, co-occurring dung beetles, we examined their eye and wing morphology. Absolute and relative eye size, and facet size were greater in the nocturnal Escarabaeus satyrus, followed by the crepuscular Scarabaeus zambesianus and then the diurnal Kheper lamarcki. The diurnal K. lamarcki had the highest wing aspect ratio (long, narrow wings), followed by the crepuscular S. zambesianus and the nocturnal E. satyrus (short, broad wings), suggesting that dim-light active species fly slower than diurnal species. In addition, the two species active in dim light had a lower wing loading than the diurnal species, indicating the need for greater manoeuvrability in the dark. Analyses of wing shape revealed that the diurnal K. lamarcki wing had a proportionally larger jugal and anal region than both dim light species. Our results show that different species of dung beetles have a combination of optical and morphological wing adaptations to support their foraging activities in diverse light conditions. [ABSTRACT FROM AUTHOR]

Abstract Insect flight is a high intensity activity, but biomechanical and metabolic requirements may vary depending on life style and feeding mode. For example, bees generally feed on pollen and nectar, whereas wasps also actively hunt and scavenge heavy prey. These variations in metabolic demands may result in different capacities of metabolic pathways in flight muscle, and utilisation some of these pathways may come at a cost of increased free radical production. To examine how metabolic requirements and oxidative stress vary between species, we explored the variation in flight mechanics and metabolism of the honeybee (Apis mellifera), bumblebee (Bombus terrestris), and German wasp (Vespula germanica). Wing structures and flight muscle properties were compared alongside measures of oxygen flux and reactive oxygen species (ROS) production from permeabilised flight muscle. The wasp wing structure is best adapted for carrying heavy loads, with the highest wing aspect ratio, lowest wing loading, and highest flight muscle ratio. Bumblebees had the lowest wing aspect ratio and flight muscle ratio, and highest wing loading. Although wasps also had the highest rates of oxygen consumption during oxidative phosphorylation, oxygen consumption did not increase in the wasp muscle following chemical uncoupling, while it did for the two bee species. While mitochondrial glycerol 3-phosphate dehydrogenase (mGPDH) mediated oxygen flux was greatest in wasps, muscle fibres released greater amounts of ROS through this pathway. Overall, the wasp has maximised lifting capacities through varying wing and flight muscle mass and by maximising OXPHOS capacities, and this accompanies elevated ROS production. Highlights • Insect flight is one of the most intense metabolic activities and biomechanical and metabolic requirements vary depending on ecology. • Pollen and nectar feeding honeybees and bumblebees, were compared to omnivorous wasps, which feed on and carry heavy prey. • Differences in flight require different metabolic capacities from flight muscle mitochondria, and highly active mitochondria elevate oxidative stress. • Wing structures and flight muscle properties indicated wasp wing structures are best adapted for carrying heavy loads. • While wasps also had the highest mitochondrial respiration rates and metabolic power, they also released the most hydrogen peroxide. [ABSTRACT FROM AUTHOR]

Thermal requirements for flight in butterflies is determined by a combination of external factors, behaviour and physical constraints. Thorax temperature of 152 butterflies was monitored with an infra-red thermometer in controlled laboratory conditions. The temperature at take-off varied from 13.4°C, for a female Heteronympha merope to 46.3°C, for a female Junonia villida. Heteronympha merope, an understorey species, had the lowest recorded take-off temperatures, with females flying at a much lower thorax temperatures than males. Among the tested butterfly species, warming-up rate was positively correlated with take-off temperature and negatively with body mass. Wing loading is a major variable in determining the thorax flight temperature. Butterflies with the highest wing-loadings experienced the highest thorax temperatures at take-off. A notable exception to this rule is Trapezites symmomus, the only Hesperiidae of our data set, which had thorax flight temperatures of 31.5°C and 34.5°C, well within the range of the observed butterflies, despite a wing load ca. five times higher. The high thorax temperature recorded in J. villida is probably linked to its high flight speed. The results highlight the importance of physical constraints such as body size on the thermal requirements for flight across a range of butterfly species.