scholarly journals Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence

2017 ◽  
Vol 7 (1) ◽  
pp. 20160086 ◽  
Author(s):  
J. D. Crall ◽  
J. J. Chang ◽  
R. L. Oppenheimer ◽  
S. A. Combes
Keyword(s):  
Field Experiments ◽  
Insect Flight ◽  
Energetic Cost ◽  
Natural Environments ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Wind Speeds ◽  
Wide Range ◽  
Outdoor Environments ◽  
Stroke Amplitude

Natural environments are characterized by variable wind that can pose significant challenges for flying animals and robots. However, our understanding of the flow conditions that animals experience outdoors and how these impact flight performance remains limited. Here, we combine laboratory and field experiments to characterize wind conditions encountered by foraging bumblebees in outdoor environments and test the effects of these conditions on flight. We used radio-frequency tags to track foraging activity of uniquely identified bumblebee ( Bombus impatiens ) workers, while simultaneously recording local wind flows. Despite being subjected to a wide range of speeds and turbulence intensities, we find that bees do not avoid foraging in windy conditions. We then examined the impacts of turbulence on bumblebee flight in a wind tunnel. Rolling instabilities increased in turbulence, but only at higher wind speeds. Bees displayed higher mean wingbeat frequency and stroke amplitude in these conditions, as well as increased asymmetry in stroke amplitude—suggesting that bees employ an array of active responses to enable flight in turbulence, which may increase the energetic cost of flight. Our results provide the first direct evidence that moderate, environmentally relevant turbulence affects insect flight performance, and suggest that flying insects use diverse mechanisms to cope with these instabilities.

scholarly journals Simultaneous measurements of three-dimensional trajectories and wingbeat frequencies of birds in the field

2018 ◽  
Vol 15 (147) ◽  
pp. 20180653 ◽  
Author(s):  
Hangjian Ling ◽  
Guillam E. Mclvor ◽  
Geoff Nagy ◽  
Sepehr MohaimenianPour ◽  
Richard T. Vaughan ◽  
...  
Keyword(s):  
Stereo Matching ◽  
Imaging System ◽  
Three Dimensional ◽  
Bird Species ◽  
Three Dimensions ◽  
Natural Environments ◽  
Flight Performance ◽  
Stereo Imaging ◽  
Wingbeat Frequency ◽  
Wide Range

Tracking the movements of birds in three dimensions is integral to a wide range of problems in animal ecology, behaviour and cognition. Multi-camera stereo-imaging has been used to track the three-dimensional (3D) motion of birds in dense flocks, but precise localization of birds remains a challenge due to imaging resolution in the depth direction and optical occlusion. This paper introduces a portable stereo-imaging system with improved accuracy and a simple stereo-matching algorithm that can resolve optical occlusion. This system allows us to decouple body and wing motion, and thus measure not only velocities and accelerations but also wingbeat frequencies along the 3D trajectories of birds. We demonstrate these new methods by analysing six flocking events consisting of 50 to 360 jackdaws ( Corvus monedula ) and rooks ( Corvus frugilegus ) as well as 32 jackdaws and 6 rooks flying in isolated pairs or alone. Our method allows us to (i) measure flight speed and wingbeat frequency in different flying modes; (ii) characterize the U-shaped flight performance curve of birds in the wild, showing that wingbeat frequency reaches its minimum at moderate flight speeds; (iii) examine group effects on individual flight performance, showing that birds have a higher wingbeat frequency when flying in a group than when flying alone and when flying in dense regions than when flying in sparse regions; and (iv) provide a potential avenue for automated discrimination of bird species. We argue that the experimental method developed in this paper opens new opportunities for understanding flight kinematics and collective behaviour in natural environments.

scholarly journals Kinematics Measurement and Power Requirements of Fruitflies at Various Flight Speeds

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4271
Author(s):  
Hao Jie Zhu ◽  
Mao Sun
Keyword(s):  
The Body ◽  
Flight Speed ◽  
Specific Power ◽  
Flight Performance ◽  
Wingbeat Frequency ◽  
Body Angle ◽  
Flying Insects ◽  
Speed Range ◽  
Full Speed ◽  
Stroke Amplitude

Energy expenditure is a critical characteristic in evaluating the flight performance of flying insects. To investigate how the energy cost of small-sized insects varies with flight speed, we measured the detailed wing and body kinematics in the full speed range of fruitflies and computed the aerodynamic forces and power requirements of the flies. As flight speed increases, the body angle decreases and the stroke plane angle increases; the wingbeat frequency only changes slightly; the geometrical angle of attack in the middle upstroke increases; the stroke amplitude first decreases and then increases. The mechanical power of the fruitflies at all flight speeds is dominated by aerodynamic power (inertial power is very small), and the magnitude of aerodynamic power in upstroke increases significantly at high flight speeds due to the increase of the drag and the flapping velocity of the wing. The specific power (power required for flight divided by insect weigh) changes little when the advance ratio is below about 0.45 and afterwards increases sharply. That is, the specific power varies with flight speed according to a J-shaped curve, unlike those of aircrafts, birds and large-sized insects which vary with flight speed according to a U-shaped curve.

Water, soil and chemical losses: field experiments and model analysis

1999 ◽  
Vol 39 (3) ◽  
pp. 93-102 ◽  
Author(s):  
P. Rossi Pisa ◽  
F. Preti ◽  
M. Rossi ◽  
F. Ventura ◽  
B. Mazzanti
Keyword(s):  
Experimental Data ◽  
Environmental Impact ◽  
Field Experiments ◽  
Nutrient Transport ◽  
Water Erosion ◽  
Natural Environments ◽  
Watershed Scale ◽  
Runoff Water ◽  
Wide Range ◽  
Soil And Water

The study of the environmental impact of water erosion, chemicals and nutrient transport by runoff water is very important to protect soil and water quality. It is possible to find much literature on this topic, but the survey data lack uniformity and represent many different agronomic or natural environments. This is due to the wide range of parameters involved in these phenomena, such as soil and geomorphologic characteristics, tillage and crop management, nutrients and pesticides used. Results of some experiments are presented in this paper. A comparison of water, soil and chemical losses has been made between experimental data and modeling outputs, both at plot and at watershed scale. The findings indicate that monitoring and modeling are two complementary instruments, both necessary for the analysis of agrochemical transport phenomena, and that the proposed methodology is useful to evaluate the related environmental impact under different scenarios.

scholarly journals Surpassing Mt. Everest: extreme flight performance of alpine bumble-bees

2014 ◽  
Vol 10 (2) ◽  
pp. 20130922 ◽  
Author(s):  
Michael E. Dillon ◽  
Robert Dudley
Keyword(s):  
Bumble Bees ◽  
Bumble Bee ◽  
Flight Performance ◽  
Excess Capacity ◽  
Wingbeat Frequency ◽  
Hovering Flight ◽  
Primary Means ◽  
Animal Flight ◽  
High Elevations ◽  
Stroke Amplitude

Animal flight at altitude involves substantial aerodynamic and physiological challenges. Hovering at high elevations is particularly demanding from the dual perspectives of lift and power output; nevertheless, some volant insects reside and fly at elevations in excess of 4000 m. Here, we demonstrate that alpine bumble-bees possess substantial aerodynamic reserves, and can sustain hovering flight under hypobaria at effective elevations in excess of 9000 m, i.e. higher than Mt. Everest. Modulation of stroke amplitude and not wingbeat frequency is the primary means of compensation for overcoming the aerodynamic challenge. The presence of such excess capacity in a high-altitude bumble-bee is surprising and suggests intermittent behavioural demands for extreme flight performance supplemental to routine foraging.

scholarly journals Power of the wingbeat: modelling the effects of flapping wings in vertebrate flight

2015 ◽  
Vol 471 (2177) ◽  
pp. 20140952 ◽  
Author(s):  
M. Klein Heerenbrink ◽  
L. C. Johansson ◽  
A. Hedenström
Keyword(s):  
Energetic Cost ◽  
Flight Performance ◽  
Large Parameter ◽  
Body Area ◽  
Wingbeat Frequency ◽  
Wing Area ◽  
Wing Motion ◽  
Animal Flight ◽  
Flight Model ◽  
Blade Element

Animal flight performance has been studied using models developed for man-made aircraft. For an aeroplane with fixed wings, the energetic cost as a function of flight speed can be expressed in terms of weight, wing span, wing area and body area, where more details are included in proportionality coefficients. Flying animals flap their wings to produce thrust. Adopting the fixed wing flight model implicitly incorporates the effects of wing flapping in the coefficients. However, in practice, these effects have been ignored. In this paper, the effects of reciprocating wing motion on the coefficients of the fixed wing aerodynamic power model for forward flight are explicitly formulated in terms of thrust requirement, wingbeat frequency and stroke-plane angle, for optimized wingbeat amplitudes. The expressions are obtained by simulating flights over a large parameter range using an optimal vortex wake method combined with a low-level blade element method. The results imply that previously assumed acceptable values for the induced power factor might be strongly underestimated. The results also show the dependence of profile power on wing kinematics. The expressions introduced in this paper can be used to significantly improve animal flight models.

Control of Winged Waterprimrose (Jussiaea decurrens) and Northern Jointvetch (Aeschynomene virginica) with Fungal Pathogens

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 497-501 ◽  
Author(s):  
C. D. Boyette ◽  
G. E. Templeton ◽  
R. J. Smith
Keyword(s):  
Oryza Sativa ◽  
Glycine Max ◽  
Fungal Pathogens ◽  
Liquid Culture ◽  
Field Experiments ◽  
Colletotrichum Gloeosporioides ◽  
Pathogenic Fungus ◽  
Field Tests ◽  
Wide Range ◽  
Growing Region

An indigenous, host-specific, pathogenic fungus that parasitizes winged waterprimrose [Jussiaea decurrens(Walt.) DC.] is endemic in the rice growing region of Arkansas. The fungus was isolated and identified asColletotrichum gloeosporioides(Penz.) Sacc. f.sp. jussiaeae(CGJ). It is highly specific for parasitism of winged waterprimrose and not parasitic on creeping waterprimrose (J. repensL. var.glabrescensKtze.), rice (Oryza sativaL.), soybeans [Glycine max(L.) Merr.], cotton (Gossypium hirsutumL.), or 4 other crops and 13 other weeds. The fungus was physiologically distinct from C.gloeosporioides(Penz.) Sacc. f. sp.aeschynomene(CGA), an endemic anthracnose pathogen of northern jointvetch[Aeschynomene virginica(L.) B.S.P.], as indicated by cross inoculations of both weeds. Culture in the laboratory and inoculation of winged waterprimrose in greenhouse, growth chamber and field experiments indicated that the pathogen was stable, specific, and virulent in a wide range of environments. The pathogen yielded large quantities of spores in liquid culture. It is suitable for control of winged waterprimrose. Winged waterprimrose and northern jointvetch were controlled in greenhouse and field tests by application of spore mixtures of CGJ and CGA at concentrations of 1 to 2 million spores/ml of each fungus in 94 L/ha of water; the fungi did not damage rice or nontarget crops.

scholarly journals Evidence-Based Landscape Architecture for Human Health and Well-Being

2020 ◽  
Vol 12 (4) ◽  
pp. 1360 ◽  
Author(s):  
Robert D. Brown ◽  
Robert C. Corry
Keyword(s):  
Human Health ◽  
Architectural Design ◽  
Landscape Architecture ◽  
Well Being ◽  
Evidence Based ◽  
Natural Environments ◽  
The People ◽  
Outdoor Environments ◽  
The Usa ◽  
Health And Well Being

More than 80% of the people in the USA and Canada live in cities. Urban development replaces natural environments with built environments resulting in limited access to outdoor environments which are critical to human health and well-being. In addition, many urban open spaces are unused because of poor design. This paper describes case studies where traditional landscape architectural design approaches would have compromised design success, while evidence-based landscape architecture (EBLA) resulted in a successful product. Examples range from school-yard design that provides safe levels of solar radiation for children, to neighborhood parks and sidewalks that encourage people to walk and enjoy nearby nature. Common characteristics for integrating EBLA into private, public, and academic landscape architecture practice are outlined along with a discussion of some of the opportunities and barriers to implementation.

scholarly journals Rattail fescue (Vulpia myuros) interference and seed production as affected by sowing time and crop density in winter wheat

Weed Science ◽  
2020 ◽  
pp. 1-10
Author(s):  
Muhammad Javaid Akhter ◽  
Per Kudsk ◽  
Solvejg Kopp Mathiassen ◽  
Bo Melander
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Seed Production ◽  
Yield Components ◽  
Field Experiments ◽  
Growing Season ◽  
Sowing Time ◽  
Growing Seasons ◽  
Crop Density ◽  
Wide Range

Abstract Field experiments were conducted in the growing seasons of 2017 to 2018 and 2018 to 2019 to evaluate the competitive effects of rattail fescue [Vulpia myuros (L.) C.C. Gmel.] in winter wheat (Triticum aestivum L.) and to assess whether delayed crop sowing and increased crop density influence the emergence, competitiveness, and fecundity of V. myuros. Cumulative emergence showed the potential of V. myuros to emerge rapidly and under a wide range of climatic conditions with no effect of crop density and variable effects of sowing time between the two experiments. Grain yield and yield components were negatively affected by increasing V. myuros density. The relationship between grain yield and V. myuros density was not influenced by sowing time or by crop density, but crop–weed competition was strongly influenced by growing conditions. Due to very different weather conditions, grain yield reductions were lower in the growing season of 2017 to 2018 than in 2018 to 2019, with maximum grain yield losses of 22% and 50% in the two growing seasons, respectively. The yield components, number of crop ears per square meter, and 1,000-kernel weight were affected almost equally, reflecting that V. myuros’s competition with winter wheat occurred both early and late in the growing season. Seed production of V. myuros was suppressed by delaying sowing and increasing crop density. The impacts of delayed sowing and increasing crop density on seed production of V. myuros highlight the potential of these cultural weed control tactics in the long-term management programs of this species.

scholarly journals On the shape of cicada’s wing leading-edge cross section

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rachel M. Starkweather ◽  
Svetlana V. Poroseva ◽  
David T. Hanson
Keyword(s):  
Cross Section ◽  
Insect Flight ◽  
Leading Edge ◽  
Flight Performance ◽  
Cross Section Shape ◽  
Section Shape ◽  
First Time

AbstractAn important role that the leading-edge cross-section shape plays in the wing flight performance is well known in aeronautics. However, little is known about the shape of the leading-edge cross section of an insect’s wing and its contribution to remarkable qualities of insect flight. In this paper, we reveal, in the first time, the shape of the leading-edge cross section of a cicada’s wing and analyze its variability along the wing. We also identify and quantify similarities in characteristic dimensions of this shape in the wings of three different cicada species.

scholarly journals Ocean Emission Effects on Aerosol-Cloud Interactions: Insights from Two Case Studies

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Armin Sorooshian ◽  
Hanh T. Duong
Keyword(s):  
Case Studies ◽  
Field Experiments ◽  
Remote Sensing Data ◽  
Anthropogenic Pollution ◽  
Cloud Microphysics ◽  
Marine Aerosols ◽  
Aerosol Cloud ◽  
First Case ◽  
Wide Range ◽  
Aerosol Cloud Interactions

Two case studies are discussed that evaluate the effect of ocean emissions on aerosol-cloud interactions. A review of the first case study from the eastern Pacific Ocean shows that simultaneous aircraft and space-borne observations are valuable in detecting links between ocean biota emissions and marine aerosols, but that the effect of the former on cloud microphysics is less clear owing to interference from background anthropogenic pollution and the difficulty with field experiments in obtaining a wide range of aerosol conditions to robustly quantify ocean effects on aerosol-cloud interactions. To address these limitations, a second case was investigated using remote sensing data over the less polluted Southern Ocean region. The results indicate that cloud drop size is reduced more for a fixed increase in aerosol particles during periods of higher ocean chlorophyll A. Potential biases in the results owing to statistical issues in the data analysis are discussed.

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