The influence of wing morphology and echolocation on the gleaning ability of the insectivorous bat Myotis tricolor

2004 ◽  
Vol 82 (12) ◽  
pp. 1854-1863 ◽  
Author(s):  
Samantha Stoffberg ◽  
David S Jacobs
Keyword(s):  
Discriminant Analysis ◽  
Foraging Behaviour ◽  
Myotis Lucifugus ◽  
The Other ◽  
Wing Morphology ◽  
Echolocation Calls ◽  
Narrow Bandwidth ◽  
Mole Crickets ◽  
Wing Tips ◽  
Wing Tip

On the basis of its external morphology, Myotis tricolor (Temminck, 1832) should be able to both aerial-feed and glean. Furthermore, this bat is known to use broadband calls of short duration, reinforcing the prediction that it gleans. However, results from this study indicate that M. tricolor does not commonly glean. This conclusion was reached after studying the foraging behaviour of M. tricolor in a flight room. We presented M. tricolor with mealworms, moths, mole crickets, beetles, and cicadas in a variety of ways that required either gleaning and (or) aerial feeding. Although M. tricolor readily took tethered prey, it did not take any of the variety of insects presented to it in a manner that required gleaning. We therefore compared its wing morphology and echolocation calls with those of several known gleaners, Nycteris thebaica E. Geoffroy, 1818, Myotis lucifugus (Le Conte, 1831), and Myotis septentrionalis (Trouessart, 1897), and an aerial forager, Neoromicia capensis (A. Smith, 1829). In a discriminant analysis wing-tip shape was the only variable to provide some degree of discrimination between species, with M. tricolor having more pointed wing tips than the known gleaners. Discriminant analysis of echolocation-call parameters grouped M. tricolor with the other Myotis species and separated it from N. capensis and N. thebaica. However, M. tricolor did not use harmonics as did the other Myotis species. The apparent failure of M. tricolor to glean might therefore be due to its relatively pointed wings and narrow-bandwidth echolocation calls, owing to the absence of harmonics in its calls.

scholarly journals The evolution of avian wing shape and previously unrecognized trends in covert feathering

2015 ◽  
Vol 282 (1816) ◽  
pp. 20151935 ◽  
Author(s):  
Xia Wang ◽  
Julia A. Clarke
Keyword(s):  
Foraging Behaviour ◽  
Wing Shape ◽  
Flight Performance ◽  
Wing Morphology ◽  
Wing Loading ◽  
Linear Measurements ◽  
Geometric Morphometric ◽  
Body Sizes ◽  
Wing Tip ◽  
Plastic Character

Avian wing shape has been related to flight performance, migration, foraging behaviour and display. Historically, linear measurements of the feathered aerofoil and skeletal proportions have been used to describe this shape. While the distribution of covert feathers, layered over the anterior wing, has long been assumed to contribute to aerofoil properties, to our knowledge no previous studies of trends in avian wing shape assessed their variation. Here, these trends are explored using a geometric–morphometric approach with landmarks describing the wing outline as well as the extent of dorsal and ventral covert feathers for 105 avian species. We find that most of the observed variation is explained by phylogeny and ecology but shows only a weak relationship with previously described flight style categories, wing loading and an investigated set of aerodynamic variables. Most of the recovered variation is in greater primary covert feather extent, followed by secondary feather length and the shape of the wing tip. Although often considered a plastic character strongly linked to flight style, the estimated ancestral wing morphology is found to be generally conservative among basal parts of most major avian lineages. The radiation of birds is characterized by successive diversification into largely distinct areas of morphospace. However, aquatic taxa show convergence in feathering despite differences in flight style, and songbirds move into a region of morphospace also occupied by basal taxa but at markedly different body sizes. These results have implications for the proposed inference of flight style in extinct taxa.

scholarly journals Preliminary investigation of use of flexible folding wing tips for static and dynamic load alleviation

2016 ◽  
Vol 121 (1235) ◽  
pp. 73-94 ◽  
Author(s):  
A. Castrichini ◽  
V. Hodigere Siddaramaiah ◽  
D.E. Calderon ◽  
J.E. Cooper ◽  
T. Wilson ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Preliminary Investigation ◽  
Aircraft Design ◽  
Dynamic Loads ◽  
Induced Drag ◽  
Aeroelastic Model ◽  
Static And Dynamic Loads ◽  
Folding Wing ◽  
Wing Tips ◽  
Wing Tip

ABSTRACTA recent consideration in aircraft design is the use of folding wing-tips with the aim of enabling higher aspect ratio aircraft with less induced drag while also meeting airport gate limitations. This study investigates the effect of exploiting folding wing-tips in flight as a device to reduce both static and dynamic loads. A representative civil jet aircraft aeroelastic model was used to explore the effect of introducing a wing-tip device, connected to the wings with an elastic hinge, on the load behaviour. For the dynamic cases, vertical discrete gusts and continuous turbulence were considered. The effects of hinge orientation, stiffness, damping and wing-tip weight on the static and dynamic response were investigated. It was found that significant reductions in both the static and dynamic loads were possible. For the case considered, a 25% increase in span using folding wing-tips resulted in almost no increase in loads.

ENERGY SAVINGS IN FORMATION FLIGHT OF PINK-FOOTED GEESE

1994 ◽  
Vol 189 (1) ◽  
pp. 251-261 ◽  
Author(s):  
C Cutts ◽  
J Speakman
Keyword(s):  
Energy Savings ◽  
Flight Path ◽  
Total Power ◽  
Maximum Information ◽  
Optimal Position ◽  
Wind Speeds ◽  
Anser Brachyrhynchus ◽  
Spacing Variation ◽  
Wing Tips ◽  
Wing Tip

Fifty-four skeins of pink-footed geese (Anser brachyrhynchus) were photographed from directly underneath to eliminate the effects of perspective distortion, and the wing-tip spacings (the distance between adjacent birds' wing tips perpendicular to the flight path at maximum wingspan) and depths (the distance between adjacent birds' body centres parallel to the flight path) were measured at the same time as local wind speeds. The photographs were used to test for savings in induced power from wing positioning relative to the predicted positions of vortices generated by other wings, using a theoretical model. The mean wing-tip spacing corresponded to a saving in induced power of 14 %, less than one-third of the maximum possible. The saving in total power might be as low as 2.4 %. The high variation in wing-tip spacing suggests that pink-footed geese found difficulty maintaining position and thus adopted a strategy of flying outboard of the optimal position that maximises savings. This may minimise the risk of straying into a zone where savings are negative. There was a significant correlation between depth and wing-tip spacing, supporting an alternative communication hypothesis, whereby the birds position themselves to obtain maximum information on their neighbour's position. In high winds, there was little change in wing-tip spacing variation but a decrease in depth variation, suggesting a shift towards more regularly spaced skeins.

Analyse discriminante et vocabulaire politique : Essai méthodologique

Res Publica ◽  
1970 ◽  
Vol 34 (1) ◽  
pp. 87-97
Author(s):  
Jacqueline Chapelle ◽  
Pierre Couvreur ◽  
Giuseppe Pagano
Keyword(s):  
Discriminant Analysis ◽  
Discriminant Function ◽  
The Other ◽  
Limited Sample ◽  
Ideological Differences ◽  
French Speaking ◽  
Political Speeches ◽  
Lexical Items

This paper aims at testing the hypothesis of growing ideological uniformity of political speeches. If political speeches lack ideological differences, it should be difficult to re-classify them only by analyzing the presence or absence of lexical items. We first worked out a method to classify political speeches and then carried a test on two speeches by leading Belgian French-speaking politicians.  The method is based on discriminant analysis. It utilizes the words most encountered in one speech and not in the other as discriminant factors. Statistical softwares then assess a discriminant function used to re-classify short parts of each speech called blocks. The most discriminating 10 factors re-classify correctly 89% of the blocks. The percentage increases to 93% with 20 factors and to 98% with 30 factors.However the results should be taken with caution because of the limited sample, the test tends to question the growing uniformity of political speeches. The sampled ones had enough specific features for allowing a rather simpte method to re-classify most parts of them correctly, even if some typically ideological items are not to be found.

Age and food hardness affect food handling by insectivorous bats

2007 ◽  
Vol 85 (9) ◽  
pp. 985-993 ◽  
Author(s):  
E.E. Fraser ◽  
M.B. Fenton
Keyword(s):  
Optimal Foraging ◽  
Feeding Behaviour ◽  
Eating Behaviour ◽  
Myotis Lucifugus ◽  
The Other ◽  
Food Handling ◽  
Insectivorous Bats ◽  
Male And Female ◽  
Food Items ◽  
And Gender

Eating behaviour can vary with age, experience, and gender, as well as food hardness. This variation can contribute to intraspecific dietary differences and may result in variable definitions of optimal foraging and decreased intraspecific competition. We quantified feeding behaviour of insectivorous bats eating hard and soft mealworm-based food items based on the bats’ ability to consume and manipulate food items, consumption time, chew frequency, and total chews to consume. Adult Myotis lucifugus (LeConte, 1831) were more successful at both consuming and manipulating mealworms and consumed mealworms more quickly, with greater chew frequency and in fewer chews, than did subadults. Adults chewed mealworm viscera more frequently than did subadults but showed no differences in the other variables. Adult Eptesicus fuscus (Beauvois, 1796) consumed mealworms more quickly and with fewer chews than did subadults but showed no differences in the other variables. There were no differences between adult and subadult E. fuscus when consuming mealworm viscera. Male and female M. lucifugus did not differ significantly when eating either mealworms or mealworm viscera. There was no change in subadult consumption time of mealworms over the summer. Age-based differences in eating abilities may play a role in defining optimal foraging and dietary composition in insectivorous bats.

Fibroblast progenitor cells of the embryonic chick limb

Development ◽  
1980 ◽  
Vol 56 (1) ◽  
pp. 191-200
Author(s):  
Stuart A. Newman
Keyword(s):  
Progenitor Cells ◽  
Cell Types ◽  
Mesenchymal Cells ◽  
The Other ◽  
Embryonic Chick ◽  
Similar Morphology ◽  
Level Characteristic ◽  
Fibroblast Progenitor Cells ◽  
Wing Tip ◽  
Mesodermal Lineage

A population of mesenchymal cells derived from the stage-25 chick wing tip gives rise to progeny of a similar morphology and to authentic fibroblasts when grown in low densityculture. Mixed clones containing both cell types are often observed. As the more rapidly proliferating fibroblasts begin to predominate in these cultures, collagen biosynthesisrises from the basal mesenchymal level to a level characteristic of mature fibroblasts. Thefibroblast progenitor is discussed relative to the other cell types of the mesodermal lineage of the developing limb.

On the taxonomy of the genus Thyridanthrax Osten Sacken in Egypt and the Kingdom of Saudi Arabia, with description of a new species (Diptera: Bombyliidae)

Zootaxa ◽  
2019 ◽  
Vol 4701 (6) ◽  
pp. 501-519 ◽  
Author(s):  
MAGDI S. EL-HAWAGRY ◽  
MAHMOUD S. ABDEL-DAYEM ◽  
HATHAL M. AL DHAFER
Keyword(s):  
Saudi Arabia ◽  
New Species ◽  
Field Trips ◽  
The Other ◽  
Wing Morphology ◽  
Key To Species ◽  
Kingdom Of Saudi Arabia ◽  
Rigorous Study ◽  
One New Species ◽  
A New Species

Egyptian and Saudi Arabian Thyridanthrax spp. collected in field trips or preserved in the Efflatoun’s insect collection in Cairo University were taxonomically studied. One new species, T. elegansoides sp. nov., is herein described, and two species, T. decipulus (Austen) and T. polyphemus (Wiedemann), are newly recorded from Egypt. Ten species are treated: one species from the Kingdom of Saudi Arabia, T. anomalus Greathead; two species from Egypt and the Kingdom of Saudi Arabia, T. decipulus (Austen) and T. perspicillaris (Loew); and seven species from Egypt: T. elegans (Wiedemann), T. elegansoides sp. nov., T. griseolus (Klug), T. incanus (Klug), T. lotus (Loew), T. obliteratus (Loew), and T. polyphemus (Wiedemann). Taxonomic comments, an identification key to species, diagnoses, and photographs of some species and genitalia are provided. Based on wing morphology and male genitalic characters, T. lotus clearly does not fit in the genus Thyridanthrax, and may need to be placed elsewhere, nevertheless it is not clear whether it can be included in any of the other currently recognized genera in the tribe Villini. It is here kept in Thyridanthrax until a more rigorous study can be conducted to better ascertain its position in the Villini. 

Bat activity over calm and turbulent water

1987 ◽  
Vol 65 (2) ◽  
pp. 219-222 ◽  
Author(s):  
Beatrix von Frenckell ◽  
Robert M. R. Barclay
Keyword(s):  
Water Level ◽  
Frequency Analysis ◽  
Myotis Lucifugus ◽  
Prey Abundance ◽  
Sticky Traps ◽  
Insect Abundance ◽  
Echolocation Calls ◽  
Bat Activity ◽  
Little Brown Bat ◽  
Turbulent Water

A comparison of the activity of the little brown bat (Myotis lucifugus) over calm pools and fast-flowing riffles was performed in southwestern Alberta. Bat activity was assessed by monitoring echolocation calls using ultrasonic detectors. Activity was higher over pools than riffles. This could be due to differences in prey abundance or accessibility in the two habitats. Alternatively, water noise at turbulent sites may interfere with the bats' echolocation abilities. Sticky traps were used to assess prey abundance, and water noise was recorded for intensity–frequency analysis. Insect abundance at the height where the bats flew (< 1 m above the water) did not differ between sites, but insects close to or at water level at calm pools may be more accessible than at fast-flowing riffles. Further, water noise at riffles may decrease the efficiency with which bats detect targets.

Postnatal development in the big-footed bat, Myotis macrodactylus: wing morphology, echolocation calls, and flight

2014 ◽  
Vol 59 (3) ◽  
pp. 435-441 ◽  
Author(s):  
Lei Wang ◽  
Aiqing Lin ◽  
Yanhong Xiao ◽  
Tinglei Jiang ◽  
Jiang Feng
Keyword(s):  
Postnatal Development ◽  
Wing Morphology ◽  
Echolocation Calls

Numerical Study in Wing Tip Vortex for a Modified Commercial Boeing Aircraft

2008 ◽  
Author(s):  
Ricardo Hernandez-Rivera ◽  
Abel Hernandez-Guerrero ◽  
Cuauhtemoc Rubio-Arana ◽  
Raul Lesso-Arroyo
Keyword(s):  
Numerical Study ◽  
Tip Vortex ◽  
Total Drag ◽  
The Core ◽  
Induced Drag ◽  
Wing Tip Vortex ◽  
Drag And Lift ◽  
Wing Tips ◽  
Wing Tip ◽  
Constant Mach Number

Recent studies have shown that the use of winglets in aircrafts wing tips have been able to reduce fuel consumption by reducing the lift-induced drag caused by wing tip vortex. This paper presents a 3-D numerical study to analyze the drag and lift forces, and the behavior of the vortexes generated in the wing tips from a modified commercial Boeing aircraft 767-300/ER. This type of aircraft does not contain winglets to control the wing tip vortex, therefore, the aerodynamic effects were analyzed adding two models of winglets to the wing tip. The first one is the vortex diffuser winglet and the second one is the tip fence winglet. The analyses were made for steady state and compressible flow, for a constant Mach number. The results show that the vortex diffuser winglet gives the best results, reducing the core velocity of the wing tip vortex up to 19%, the total drag force of the aircraft up to 3.6% and it leads to a lift increase of up to 2.4% with respect to the original aircraft without winglets.

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