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1.
Zoolog Sci ; 38(5): 427-435, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34664917

RESUMO

No scales of most lepidopterans (butterflies and moths) detach from the wings through fluttering. However, in the pellucid hawk moth, Cephonodes hylas, numerous scales detach from a large region of the wing at initial take-off after eclosion; consequently, a large transparent region without scales appears in the wing. Even after this programmed detachment of scales (d-scales), small regions along the wing margin and vein still have scales attached (a-scales). To investigate the scale detachment mechanism, we analyzed the scale detachment process using video photography and examined the morphology of both d- and a-scales using optical and scanning electron microscopy. This study showed that d-scale detachment only occurs through fluttering and that d-scales are obviously morphologically different from a-scales. Although a-scales are morphologically common lepidopteran scales, d-scales have four distinctive features. First, d-scales are much larger than a-scales. Second, the d-scale pedicel, which is the slender base of the scale, is tapered; that of the a-scale is columnar. Third, the socket on the wing surface into which the pedicel is inserted is much smaller for d-scales than a-scales. Fourth, the d-scale socket density is much lower than the a-scale socket density. This novel scale morphology likely helps to facilitate scale detachment through fluttering and, furthermore, increases wing transparency.


Assuntos
Mariposas/anatomia & histologia , Asas de Animais/anatomia & histologia , Animais , Voo Animal/fisiologia , Metamorfose Biológica , Mariposas/crescimento & desenvolvimento , Asas de Animais/ultraestrutura
2.
J R Soc Interface ; 18(183): 20210518, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34665973

RESUMO

Insect wings are hybrid structures that are typically composed of veins and solid membranes. In some of the smallest flying insects, however, the wing membrane is replaced by hair-like bristles attached to a solid root. Bristles and membranous wing surfaces coexist in small but not in large insect species. There is no satisfying explanation for this finding as aerodynamic force production is always smaller in bristled than solid wings. This computational study suggests that the diversity of wing structure in small insects results from aerodynamic efficiency rather than from the requirements to produce elevated forces for flight. The tested wings vary from fully membranous to sparsely bristled and were flapped around a wing root with lift- and drag-based wing kinematic patterns and at different Reynolds numbers (Re). The results show that the decrease in aerodynamic efficiency with decreasing surface solidity is significantly smaller at Re = 4 than Re = 57. A replacement of wing membrane by bristles thus causes less change in energetic costs for flight in small compared to large insects. As a consequence, small insects may fly with bristled and solid wing surfaces at similar efficacy, while larger insects must use membranous wings for an efficient production of flight forces. The above findings are significant for the biological fitness and dispersal of insects that fly at elevated energy expenditures.


Assuntos
Voo Animal , Modelos Biológicos , Animais , Fenômenos Biomecânicos , Insetos , Asas de Animais
3.
Biol Lett ; 17(10): 20210430, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34665992

RESUMO

Olfactory tracking generally sacrifices speed for sensitivity, but some fast-moving animals appear surprisingly efficient at foraging by smell. Here, we analysed the olfactory tracking strategies of flying bats foraging for fruit. Fruit- and nectar-feeding bats use odour cues to find food despite the sensory challenges derived from fast flight speeds and echolocation. We trained Jamaican fruit-eating bats (Artibeus jamaicensis) to locate an odour reward and reconstructed their flight paths in three-dimensional space. Results confirmed that bats relied upon olfactory cues to locate a reward. Flight paths revealed a combination of odour- and memory-guided search strategies. During 'inspection flights', bats significantly reduced flight speeds and flew within approximately 6 cm of possible targets to evaluate the presence or absence of the odour cue. This behaviour combined with echolocation explains how bats maximize foraging efficiency while compensating for trade-offs associated with olfactory detection and locomotion.


Assuntos
Quirópteros , Ecolocação , Animais , Sinais (Psicologia) , Voo Animal , Odorantes , Olfato
4.
Proc Biol Sci ; 288(1958): 20211603, 2021 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-34493076

RESUMO

Flying over the open sea is energetically costly for terrestrial birds. Despite this, over-water journeys of many birds, sometimes hundreds of kilometres long, are uncovered by bio-logging technology. To understand how these birds afford their flights over the open sea, we investigated the role of atmospheric conditions, specifically wind and uplift, in subsidizing over-water flight at a global scale. We first established that ΔT, the temperature difference between sea surface and air, is a meaningful proxy for uplift over water. Using this proxy, we showed that the spatio-temporal patterns of sea-crossing in terrestrial migratory birds are associated with favourable uplift conditions. We then analysed route selection over the open sea for five facultative soaring species, representative of all major migratory flyways. The birds maximized wind support when selecting their sea-crossing routes and selected greater uplift when suitable wind support was available. They also preferred routes with low long-term uncertainty in wind conditions. Our findings suggest that, in addition to wind, uplift may play a key role in the energy seascape for bird migration that in turn determines strategies and associated costs for birds crossing ecological barriers such as the open sea.


Assuntos
Voo Animal , Vento , Migração Animal , Animais , Aves , Água
5.
J R Soc Interface ; 18(182): 20210567, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34493092

RESUMO

Honeybees foraging and recruiting nest-mates by performing the waggle dance need to be able to gauge the flight distance to the food source regardless of the wind and terrain conditions. Previous authors have hypothesized that the foragers' visual odometer mathematically integrates the angular velocity of the ground image sweeping backward across their ventral viewfield, known as translational optic flow. The question arises as to how mathematical integration of optic flow (usually expressed in radians/s) can reliably encode distances, regardless of the height and speed of flight. The vertical self-oscillatory movements observed in honeybees trigger expansions and contractions of the optic flow vector field, yielding an additional visual cue called optic flow divergence. We have developed a self-scaled model for the visual odometer in which the translational optic flow is scaled by the visually estimated current clearance from the ground. In simulation, this model, which we have called SOFIa, was found to be reliable in a large range of flight trajectories, terrains and wind conditions. It reduced the statistical dispersion of the estimated flight distances approximately 10-fold in comparison with the mathematically integrated raw optic flow model. The SOFIa model can be directly implemented in robotic applications based on minimalistic visual equipment.


Assuntos
Voo Animal , Robótica , Animais , Abelhas , Vento
6.
Sensors (Basel) ; 21(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34577196

RESUMO

Unmanned Aerial Vehicles (UAVs) have slowly but steadily emerged as a research and commercial hotspot because of their widespread applications. Due to their agility, compact size, and ability to integrate multiple sensors, they are mostly sought for applications that require supplementing human effort in risky and monotonous missions. Despite all of these advantages, rotorcrafts, in general, are limited by their endurance and power-intensive flight requirements, which consequently affect the time of flight and operational range. On the other hand, fixed-wing aircrafts have an extended range, as the entire thrust force is along the direction of motion and are inherently more stable but are limited by their takeoff and landing strip requirements. One of the potential solutions to increase the endurance of VTOL rotorcrafts (Vertical Take-Off and Landing Vehicles) was to exploit the thrust vectoring ability of the individual actuators in multi-rotors, which would enable take-off and hovering as a VTOL vehicle and flight as a fixed-wing aircraft. The primary aim of this paper is to lay out the overall design process of a Hybrid VTOL tilt-rotor UAV from the initial conceptual sketch to the final fabricated prototype. The novelty of the design lies in achieving thrust vectoring capabilities in a fixed-wing platform with minimum actuation and no additional control complexity. This paper presents novel bi-copter that has been designed to perform as a hybrid configuration in both VTOL and fixed wing conditions with minimum actuators in comparison to existing designs. The unified dynamic modelling along with the approximation of multiple aerodynamic coefficients by numerical simulations is also presented. The overall conceptual design, dynamic modeling, computational simulation, and experimental analysis of the novel hybrid fixed-wing bi-copter with thrust vectoring capabilities aiming to substantially increase the flight range and endurance compared to the conventional aircraft rotorcraft configurations are presented.


Assuntos
Aeronaves , Voo Animal , Simulação por Computador , Humanos , Fenômenos Mecânicos
7.
Sci Rep ; 11(1): 17608, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475464

RESUMO

The recent emergence of Xylella fastidiosa in Europe is a major threat to agriculture, including olive, almond and grape. Philaenus spumarius is the predominant vector of X. fastidiosa in Europe. Understanding vector movement is critical for developing effective control measures against bacterial spread. In this study, our goal was to set up a flight-mill protocol to assess P. spumarius flight potential and to analyse how different variables may affect its flight behaviour. We found that P. spumarius was able to fly ≈ 500 m in 30 min with a maximum single flight of 5.5 km in 5.4 h. Based on the observations, the flight potential of the females was higher in spring and autumn than in summer, and that of the males was highest in autumn. Moreover, we found that P. spumarius had a higher flight potential during the morning and the night than during the afternoon. Our results revealed that P. spumarius is likely to disperse much further than the established sizes of the infected and buffer zones designated by the EU. This knowledge on the flight potential of P. spumarius will be critical for improving management actions against P. spumarius and the spread of X. fastidiosa in Europe.


Assuntos
Hemípteros/fisiologia , Insetos Vetores/fisiologia , Doenças das Plantas/microbiologia , Xylella/fisiologia , Distribuição Animal , Animais , Europa (Continente) , Feminino , Voo Animal , Hemípteros/microbiologia , Insetos Vetores/microbiologia , Masculino
8.
J Morphol ; 282(11): 1698-1707, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34570390

RESUMO

In dictating the relative distances between the elbow, shoulder and wrist, avian brachial index (BI = humerus/radius-ulna length) likely influences wing kinematics and, therefore, might predict extinct avian flight capability. This underpins the hypothesis that non-neornithine Mesozoic avialans with relatively low BIs (associated with improved flight capabilities) restricted neornithine diversification until after the Cretaceous-Paleogene boundary. Here, correlations between flight metrics (wingbeat frequency (f), stroke angle (θ), wing loading (Q) and aspect ratio) and BI were investigated and vice versa. Additionally, the evolutionary model best describing the phylogenetic distribution of BI, and the temporal patterns in BI, flight metrics, body mass (Mb ), and size-corrected humerus (Lh ) and radius-ulna (Lru ) length were determined. BI was best described by Ornstein-Uhlenbeck processes, with low α values indicating a gradual shift towards a future theoretical optimum. BI also decreased overall through evolutionary time with the flight metrics mirroring temporal patterns of change in BI. Mb , Lh and Lru overall decreased apart from increases in Lh and Lru following the middle-late Miocene (also leading to BI increasing) due to diversifications of the Anatinae and Sphenisciformes. Lh overall decreased further than Lru. Consequently, decreasing Lh mainly contributed to decreasing BI through evolutionary time, implying flight performance increased through neornithine evolution. However, the timings of radiations in these variables implies an Eocene radiation of neornthine flight ecology rather than a rapid expansion into niches vacated by non-neornithine Mesozoic avialians following the Cretaceous-Paleogene boundary. Multiple regressions showed f, θ and Q explained 60% of variation in BI. However, unequivocally evaluating whether BI is related to wing movement (and flight capability) requires direct measures of wing movement for many species, which are currently unavailable. Finally, the findings here and previously observed clade-specificity in BI, suggest flight ecology may also be clade-specific. Hence, the utility of phylogeny in predicting flight ecology requires exploration.


Assuntos
Evolução Biológica , Aves , Animais , Ecologia , Voo Animal , Filogenia , Asas de Animais
9.
Nature ; 597(7877): 480-481, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34552248

Assuntos
Voo Animal , Robótica
10.
Elife ; 102021 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-34523418

RESUMO

Insects have evolved diverse and remarkable strategies for navigating in various ecologies all over the world. Regardless of species, insects share the presence of a group of morphologically conserved neuropils known collectively as the central complex (CX). The CX is a navigational center, involved in sensory integration and coordinated motor activity. Despite the fact that our understanding of navigational behavior comes predominantly from ants and bees, most of what we know about the underlying neural circuitry of such behavior comes from work in fruit flies. Here, we aim to close this gap, by providing the first comprehensive map of all major columnar neurons and their projection patterns in the CX of a bee. We find numerous components of the circuit that appear to be highly conserved between the fly and the bee, but also highlight several key differences which are likely to have important functional ramifications.


Assuntos
Abelhas/fisiologia , Comportamento Animal , Conectoma , Voo Animal , Vias Neurais/fisiologia , Neurópilo/fisiologia , Comportamento Espacial , Animais , Abelhas/ultraestrutura , Drosophila melanogaster/fisiologia , Drosophila melanogaster/ultraestrutura , Vias Neurais/ultraestrutura , Neurópilo/ultraestrutura , Especificidade da Espécie
11.
PLoS One ; 16(9): e0257097, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34506561

RESUMO

Ceratitis capitata (medfly) is one of the most devastating crop pests worldwide. The Sterile Insect Technique (SIT) is a control method that is based on the mass rearing of males, their sterilization, and release in the field. However, the effectiveness of the technique depends on the quality of the released males and their fitness. We previously isolated and selected a probiotic bacteria (Enterobacter sp.), from wild-caught medflies, according to criteria that improved biological quality traits of reared medfly males.We firstly evaluated the impact of the irradiation on the expression of different immune and stress genes in the medfly sterile males. Expression was measured at differents time points ranging from 0 to 168 h after irradiation to capture the response of genes with distinct temporal expression patterns. Then, we supplemented the larval diet with previously isolated Enterobacter sp.strain, live and autoclaved at various concentrations to see whether the probiotic treatments affect, through their protective role, the gene expression level, and quality traits. The irradiation had significant effect on the genes attacin, cecropin, PGPR-LC, hsp23, and hsp70 level expression. The expression of attacin and PGPR-LC was up-regulated while that of cecropin was down-regulated. Hsp genes showed decreased levels between 0 and 18 h to peak at 72 h. However, the supplementation of the probiotic strain, either live or autoclaved, was statistically significant only for attacingene. However, significant interaction time x probiotic was noticed for attacin, cecropin, hsp23 and hsp70. The probiotic treatments also improved the quality control parameters like pupal weight. From this work we can conclude that a consortium of parabiotics (autoclaved probiotics) treatment will be recommended in insectaries considering both the beneficial effects on mass reared insects and its general safety for insectary workers and for environment.


Assuntos
Ceratitis capitata/imunologia , Ceratitis capitata/efeitos da radiação , Dieta , Imunidade/efeitos dos fármacos , Infertilidade Masculina/imunologia , Controle Biológico de Vetores , Probióticos/farmacologia , Estresse Fisiológico/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Ceratitis capitata/genética , Radioisótopos de Cobalto , Feminino , Voo Animal/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos da radiação , Imunidade/genética , Imunidade/efeitos da radiação , Infertilidade Masculina/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Masculino , Pupa/efeitos dos fármacos , Estatística como Assunto , Estresse Fisiológico/genética
12.
Proc Biol Sci ; 288(1956): 20210677, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34344177

RESUMO

The evolution of flapping flight is linked to the prolific success of insects. Across Insecta, wing morphology diversified, strongly impacting aerodynamic performance. In the presence of ecological opportunity, discrete adaptive shifts and early bursts are two processes hypothesized to give rise to exceptional morphological diversification. Here, we use the sister-families Sphingidae and Saturniidae to answer how the evolution of aerodynamically important traits is linked to clade divergence and through what process(es) these traits evolve. Many agile Sphingidae evolved hover feeding behaviours, while adult Saturniidae lack functional mouth parts and rely on a fixed energy budget as adults. We find that Sphingidae underwent an adaptive shift in wing morphology coincident with life history and behaviour divergence, evolving small high aspect ratio wings advantageous for power reduction that can be moved at high frequencies, beneficial for flight control. By contrast, Saturniidae, which do not feed as adults, evolved large wings and morphology which surprisingly does not reduce aerodynamic power, but could contribute to their erratic flight behaviour, aiding in predator avoidance. We suggest that after the evolution of flapping flight, diversification of wing morphology can be potentiated by adaptative shifts, shaping the diversity of wing morphology across insects.


Assuntos
Mariposas , Animais , Fenômenos Biomecânicos , Voo Animal , Humanos , Insetos , Modelos Biológicos , Asas de Animais
13.
J R Soc Interface ; 18(181): 20210222, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34343451

RESUMO

Flying animals resort to fast, large-degree-of-freedom motion of flapping wings, a key feature that distinguishes them from rotary or fixed-winged robotic fliers with limited motion of aerodynamic surfaces. However, flapping-wing aerodynamics are characterized by highly unsteady and three-dimensional flows difficult to model or control, and accurate aerodynamic force predictions often rely on expensive computational or experimental methods. Here, we developed a computationally efficient and data-driven state-space model to dynamically map wing kinematics to aerodynamic forces/moments. This model was trained and tested with a total of 548 different flapping-wing motions and surpassed the accuracy and generality of the existing quasi-steady models. This model used 12 states to capture the unsteady and nonlinear fluid effects pertinent to force generation without explicit information of fluid flows. We also provided a comprehensive assessment of the control authority of key wing kinematic variables and found that instantaneous aerodynamic forces/moments were largely predictable by the wing motion history within a half-stroke cycle. Furthermore, the angle of attack, normal acceleration and pitching motion had the strongest effects on the aerodynamic force/moment generation. Our results show that flapping flight inherently offers high force control authority and predictability, which can be key to developing agile and stable aerial fliers.


Assuntos
Voo Animal , Asas de Animais , Animais , Fenômenos Biomecânicos , Modelos Biológicos , Simulação de Ambiente Espacial
14.
J Insect Physiol ; 134: 104293, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34389411

RESUMO

Winged insects vary greatly in size, from tiny wasps (0.015 mg) to large moths (1.6 g). Previous studies on the power requirements of insect flight focused on relatively large insects; those of miniature insects remain relatively unknown. In this study the power requirements of a series of miniature insects were calculated, and changes with size across a range of insect sizes were investigated. Aerodynamic power was computed by numerically solving the Navier-Stokes equation, and inertial power was computed analytically. Comparison analysis was then conducted on the power requirements of miniature and large insects. Despite a 100,000-fold weight difference, the required power per unit insect mass, referred to as mass-specific power, was approximately equal for all the insects examined. This finding is explained as follows. Power is approximately proportional to the product of the wing speed and the wing drag per unit weight (i.e., "drag-to-lift ratio"). When insect size decreased, wing speed decreased (due to reduced wing-length), while wing drag increased (due to increased air-viscosity), resulting in an approximately unchanged mass-specific power. For large or small insects, flight power is derived from the same type of muscles (striated). Assuming that the mean power per unit muscle mass is the same under the same type of muscle, the above size/specific-power relation indicates that the ratio of flight-muscle mass to insect mass is the same for different sized insects.


Assuntos
Tamanho Corporal , Voo Animal/fisiologia , Insetos/fisiologia , Asas de Animais/fisiologia , Animais , Fenômenos Biomecânicos , Simulação por Computador , Modelos Biológicos
15.
J Insect Physiol ; 134: 104297, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34403656

RESUMO

Bumble bees are eusocial, with distinct worker and queen castes that vary strikingly in size and life-history. The smaller workers rely on energetically-demanding foraging flights to collect resources for rearing brood. Queens can be 3 to 4 times larger than workers, flying only for short periods in fall and again in spring after overwintering underground. These differences between castes in size and life history may be reflected in hypoxia tolerance. When oxygen demand exceeds supply, oxygen delivery to the tissues can be compromised. Previous work revealed hypermetric scaling of tracheal system volume of worker bumble bees (Bombus impatiens); larger workers had much larger tracheal volumes, likely to facilitate oxygen delivery over longer distances. Despite their much larger size, queens had relatively small tracheal volumes, potentially limiting their ability to deliver oxygen and reducing their ability to respond to hypoxia. However, these morphological measurements only indirectly point to differences in respiratory capacity. To directly assess size- and caste-related differences in tolerance to low oxygen, we measured critical PO2 (Pcrit; the ambient oxygen level below which metabolism cannot be maintained) during both rest and flight of worker and queen bumble bees. Queens and workers had similar Pcrit values during both rest and flight. However, during flight in oxygen levels near the Pcrit, mass-specific metabolic rates declined precipitously with mass both across and within castes, suggesting strong size limitations on oxygen delivery, but only during extreme conditions, when demand is high and supply is low. Together, these data suggest that the comparatively small tracheal systems of queen bumble bees do not limit their ability to deliver oxygen except in extreme conditions; they pay little cost for filling body space with eggs rather than tracheal structures.


Assuntos
Abelhas , Voo Animal/fisiologia , Oxigênio/metabolismo , Animais , Abelhas/metabolismo , Abelhas/fisiologia , Hipóxia , Respiração , Fenômenos Fisiológicos Respiratórios
16.
PLoS One ; 16(8): e0254159, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34351932

RESUMO

Wind farms can have two broad potential adverse effects on birds via antagonistic processes: displacement from the vicinity of turbines (avoidance), or death through collision with rotating turbine blades. These effects may not be mutually exclusive. Using detailed data from 99 turbines at two wind farms in central Scotland and thousands of GPS-telemetry data from dispersing golden eagles, we tested three hypotheses. Before-and-after-operation analyses supported the hypothesis of avoidance: displacement was reduced at turbine locations in more preferred habitat and with more preferred habitat nearby. After-operation analyses (i.e. from the period when turbines were operational) showed that at higher wind speeds and in highly preferred habitat eagles were less wary of turbines with motionless blades: rejecting our second hypothesis. Our third hypothesis was supported, since at higher wind speeds eagles flew closer to operational turbines; especially-once more-turbines in more preferred habitat. After operation, eagles effectively abandoned inner turbine locations, and flight line records close to rotor blades were rare. While our study indicated that whole-wind farm functional habitat loss through avoidance was the substantial adverse impact, we make recommendations on future wind farm design to minimise collision risk further. These largely entail developers avoiding outer turbine locations which are in and surrounded by swathes of preferred habitat. Our study illustrates the insights which detailed case studies of large raptors at wind farms can bring and emphasises that the balance between avoidance and collision can have several influences.


Assuntos
Conservação dos Recursos Naturais , Águias/fisiologia , Ecossistema , Voo Animal , Telemetria , Vento , Migração Animal , Animais , Escócia
17.
Nature ; 596(7872): 404-409, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34381211

RESUMO

As animals navigate on a two-dimensional surface, neurons in the medial entorhinal cortex (MEC) known as grid cells are activated when the animal passes through multiple locations (firing fields) arranged in a hexagonal lattice that tiles the locomotion surface1. However, although our world is three-dimensional, it is unclear how the MEC represents 3D space2. Here we recorded from MEC cells in freely flying bats and identified several classes of spatial neurons, including 3D border cells, 3D head-direction cells, and neurons with multiple 3D firing fields. Many of these multifield neurons were 3D grid cells, whose neighbouring fields were separated by a characteristic distance-forming a local order-but lacked any global lattice arrangement of the fields. Thus, whereas 2D grid cells form a global lattice-characterized by both local and global order-3D grid cells exhibited only local order, creating a locally ordered metric for space. We modelled grid cells as emerging from pairwise interactions between fields, which yielded a hexagonal lattice in 2D and local order in 3D, thereby describing both 2D and 3D grid cells using one unifying model. Together, these data and model illuminate the fundamental differences and similarities between neural codes for 3D and 2D space in the mammalian brain.


Assuntos
Quirópteros/fisiologia , Percepção de Profundidade/fisiologia , Córtex Entorrinal/citologia , Córtex Entorrinal/fisiologia , Células de Grade/fisiologia , Modelos Neurológicos , Animais , Comportamento Animal/fisiologia , Voo Animal/fisiologia , Masculino
18.
J Insect Physiol ; 133: 104290, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34352283

RESUMO

Adult body size in insects can be influenced by environmental conditions during larval growth. The effect of such intraspecific variation in body mass on flight performance is poorly understood. In Batocera rufomaculata, a large tree boring beetle, adults emerging from larvae that developed in a dying host tree, and therefore, under nutrient-deprived diet conditions, are smaller but have an elevated long-distance flight capability compared to larger conspecifics that developed in viable host trees. The improved endurance for long-distance flight in the smaller individuals appears to contradict the interspecific trend in flying animals of a decrease in Cost of Transport (CoT) with increased body mass. To explore the relationship between intraspecific variation in body size and power expended during steady forward flight, we flew these beetles tethered in a wind tunnel and compared the flapping kinematics and power output of individuals varying in body mass (1-7 gr). Concurrently, we measured the forces the insects applied on the tether allowing us to evaluate the tethering effects and correct for them. From the flapping kinematics we estimated the mechanical power expended using a quasi-steady blade-element model. We found that muscle mass-specific power did not differ between small and large individuals flying at the same wind (flight) speed in the tunnel. Consequently, the CoT of B. rufomaculata does not vary with body mass. Such invariance of mass-specific power with body mass may aid the dispersal of smaller individuals from deteriorating host trees to new ones.


Assuntos
Besouros/fisiologia , Voo Animal , Asas de Animais/fisiologia , Animais , Tamanho Corporal , Feminino , Masculino
19.
Sci Rep ; 11(1): 15984, 2021 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-34362958

RESUMO

Animals swim in water, fly in air, or dive into water to find mates, chase prey, or escape from predators. Even though these locomotion modes are phenomenologically distinct, we can rationalize the underlying hydrodynamic forces using a unified fluid potential model. First, we review the previously known complex potential of a moving thin plate to describe circulation and pressure around the body. Then, the impact force in diving or thrust force in swimming and flying are evaluated from the potential flow model. For the impact force, we show that the slamming or impact force of various ellipsoid-shaped bodies of animals increases with animal weight, however, the impact pressure does not vary much. For fliers, birds and bats follow a linear correlation between thrust lift force and animal weight. For swimming animals, we present a scaling of swimming speed as a balance of thrust force with drag, which is verified with biological data. Under this framework, three distinct animal behaviors (i.e., swimming, flying, and diving) are similar in that a thin appendage displaces and pressurizes a fluid, but different in regards to the surroundings, being either fully immersed in a fluid or at a fluid interface.


Assuntos
Comportamento Animal/fisiologia , Mergulho/fisiologia , Voo Animal , Modelos Biológicos , Natação , Animais , Fenômenos Biomecânicos , Aves , Quirópteros , Hidrodinâmica
20.
PLoS Comput Biol ; 17(8): e1009195, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34379622

RESUMO

Animals rely on sensory feedback to generate accurate, reliable movements. In many flying insects, strain-sensitive neurons on the wings provide rapid feedback that is critical for stable flight control. While the impacts of wing structure on aerodynamic performance have been widely studied, the impacts of wing structure on sensing are largely unexplored. In this paper, we show how the structural properties of the wing and encoding by mechanosensory neurons interact to jointly determine optimal sensing strategies and performance. Specifically, we examine how neural sensors can be placed effectively on a flapping wing to detect body rotation about different axes, using a computational wing model with varying flexural stiffness. A small set of mechanosensors, conveying strain information at key locations with a single action potential per wingbeat, enable accurate detection of body rotation. Optimal sensor locations are concentrated at either the wing base or the wing tip, and they transition sharply as a function of both wing stiffness and neural threshold. Moreover, the sensing strategy and performance is robust to both external disturbances and sensor loss. Typically, only five sensors are needed to achieve near-peak accuracy, with a single sensor often providing accuracy well above chance. Our results show that small-amplitude, dynamic signals can be extracted efficiently with spatially and temporally sparse sensors in the context of flight. The demonstrated interaction of wing structure and neural encoding properties points to the importance of understanding each in the context of their joint evolution.


Assuntos
Voo Animal/fisiologia , Insetos/anatomia & histologia , Insetos/fisiologia , Modelos Biológicos , Asas de Animais/anatomia & histologia , Asas de Animais/inervação , Potenciais de Ação/fisiologia , Animais , Evolução Biológica , Fenômenos Biomecânicos , Biologia Computacional , Simulação por Computador , Retroalimentação Sensorial/fisiologia , Manduca/anatomia & histologia , Manduca/fisiologia , Mecanorreceptores/fisiologia , Modelos Neurológicos , Rotação , Asas de Animais/fisiologia
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