scholarly journals Commuting fruit bats beneficially modulate their flight in relation to wind

2014 ◽  
Vol 281 (1782) ◽  
pp. 20140018 ◽  
Author(s):  
Nir Sapir ◽  
Nir Horvitz ◽  
Dina K. N. Dechmann ◽  
Jakob Fahr ◽  
Martin Wikelski
Keyword(s):  
Convergent Evolution ◽  
Migratory Birds ◽  
Fruit Bats ◽  
Movement Model ◽  
Cost Of Transport ◽  
Wind Drift ◽  
Optimal Movement ◽  
The Cost ◽  
Free Ranging ◽  
Eidolon Helvum

When animals move, their tracks may be strongly influenced by the motion of air or water, and this may affect the speed, energetics and prospects of the journey. Flying organisms, such as bats, may thus benefit from modifying their flight in response to the wind vector. Yet, practical difficulties have so far limited the understanding of this response for free-ranging bats. We tracked nine straw-coloured fruit bats ( Eidolon helvum ) that flew 42.5 ± 17.5 km (mean ± s.d.) to and from their roost near Accra, Ghana. Following detailed atmospheric simulations, we found that bats compensated for wind drift, as predicted under constant winds, and decreased their airspeed in response to tailwind assistance such that their groundspeed remained nearly constant. In addition, bats increased their airspeed with increasing crosswind speed. Overall, bats modulated their airspeed in relation to wind speed at different wind directions in a manner predicted by a two-dimensional optimal movement model. We conclude that sophisticated behavioural mechanisms to minimize the cost of transport under various wind conditions have evolved in bats. The bats’ response to the wind is similar to that reported for migratory birds and insects, suggesting convergent evolution of flight behaviours in volant organisms.

scholarly journals Lagos Bat Virus Infection Dynamics in Free-Ranging Straw-Colored Fruit Bats (Eidolon helvum)

2017 ◽  
Vol 2 (3) ◽  
pp. 25 ◽  
Author(s):  
Richard Suu-Ire ◽  
Anthony Fooks ◽  
Ashley Banyard ◽  
David Selden ◽  
Kofi Amponsah-Mensah ◽  
...  
Keyword(s):  
Virus Infection ◽  
Fruit Bats ◽  
Bat Virus ◽  
Infection Dynamics ◽  
Free Ranging ◽  
Eidolon Helvum

scholarly journals Persistence of Multiple Paramyxoviruses in a Closed Captive Colony of Fruit Bats (Eidolon helvum)

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1659 ◽  
Author(s):  
Louise Gibson ◽  
Maria Puig Ribas ◽  
James Kemp ◽  
Olivier Restif ◽  
Richard D. Suu-Ire ◽  
...  
Keyword(s):  
Urban Areas ◽  
Emerging Diseases ◽  
Fruit Bats ◽  
Fatal Disease ◽  
Zoonotic Viruses ◽  
High Incidence ◽  
Natural Hosts ◽  
Free Ranging ◽  
Eidolon Helvum

Bats have been identified as the natural hosts of several emerging zoonotic viruses, including paramyxoviruses, such as Hendra and Nipah viruses, that can cause fatal disease in humans. Recently, African fruit bats with populations that roost in or near urban areas have been shown to harbour a great diversity of paramyxoviruses, posing potential spillover risks to public health. Understanding the circulation of these viruses in their reservoir populations is essential to predict and prevent future emerging diseases. Here, we identify a high incidence of multiple paramyxoviruses in urine samples collected from a closed captive colony of circa 115 straw-coloured fruit bats (Eidolon helvum). The sequences detected have high nucleotide identities with those derived from free ranging African fruit bats and form phylogenetic clusters with the Henipavirus genus, Pararubulavirus genus and other unclassified paramyxoviruses. As this colony had been closed for 5 years prior to this study, these results indicate that within-host paramyxoviral persistence underlies the role of bats as reservoirs of these viruses.

Flight Speed and Directional Responses to Wind by Migrating Canada Geese

The Auk ◽  
1984 ◽  
Vol 101 (2) ◽  
pp. 342-348 ◽  
Author(s):  
Michael L. Wege ◽  
Dennis G. Raveling
Keyword(s):  
Metabolic Rate ◽  
Wind Direction ◽  
Time Of Flight ◽  
Weather Conditions ◽  
Canada Geese ◽  
Cost Of Transport ◽  
Wind Drift ◽  
Visual Reference ◽  
The Cost ◽  
Goal Direction

Abstract We monitored headings, flight speeds, and time of flight of nine transmittertagged giant Canada geese (Branta canadensis maxima) during 10 different autumn migration flights during which data on wind directions and speeds were also available. Destination of these individuals was known because of previous observations of the same birds. This enabled us to evaluate their headings with respect to wind drift. As the magnitude of the following component of the wind increased, air speeds of migrating geese declined while ground speeds were not significantly changed. Therefore, the cost of transport over the ground, and probably metabolic rate, were minimized. Headings of migrant geese varied systematically and significantly with wind direction, but track directions did not deviate significantly from the goal direction. Thus, the geese compensated for wind drift. Visual reference to landmarks may have been the cue used to correct for drift, as weather conditions were such that geese could see the ground.

scholarly journals Persistence of Multiple Paramyxoviruses in a Closed Captive Colony of Fruit Bats (Eidolon helvum)

2021 ◽  
Author(s):  
Louise Gibson ◽  
Maria Puig Rebas ◽  
James Kemp ◽  
Olivier Restif ◽  
Richard D. Suu-Ire ◽  
...  
Keyword(s):  
Urban Areas ◽  
Emerging Diseases ◽  
Fruit Bats ◽  
Fatal Disease ◽  
Zoonotic Viruses ◽  
High Incidence ◽  
Natural Hosts ◽  
Free Ranging ◽  
Eidolon Helvum

Bats have been identified as the natural hosts of several emerging zoonotic viruses, including paramyxoviruses, such as Hendra and Nipah viruses, that can cause fatal disease in humans. Recently, African fruit bats with populations that roost in or near urban areas have been shown to harbour a great diversity of paramyxoviruses, posing potential spillover risks to public health. Understanding the circulation of these viruses in their reservoir populations is essential to predict and prevent future emerging diseases. Here, we identify a high incidence of multiple paramyxoviruses in urine samples collected from a closed, captive colony of circa. 115 straw-coloured fruit bats (Eidolon helvum). The sequences detected have high nucleotide identities with those derived from free ranging African fruit bats and form phylogenetic clusters with the Henipavirus genus, Pararubulavirus genus and other unclassified paramyxoviruses. As this colony had been closed for 5 years prior to this study, these results indicate that within-host paramyxoviral persistence underlies the role of bats as reservoirs of these viruses.

scholarly journals Flight Physiology of Intermediate-Sized Fruit Bats (Pteropodidae)

1986 ◽  
Vol 120 (1) ◽  
pp. 79-103 ◽  
Author(s):  
ROGER E. CARPENTER
Keyword(s):  
Wind Tunnel ◽  
Size Range ◽  
Power Input ◽  
Relative Power ◽  
Fruit Bats ◽  
Cost Of Transport ◽  
Ambient Temperatures ◽  
Power Inputs ◽  
The Cost ◽  
Respiratory Evaporation

Up to eight physiological parameters were measured on members of four species of fruit bats with a size range of 0.188-0.650 kg as they flew in a wind tunnel. Regression lines were calculated for the relationships between body masses of bats and their power inputs (P1), heart and respiratory rates. These were compared to similar relationships for flying birds. Respiratory evaporation dissipated only 10% of the heat produced. At ambient temperatures (Ta) above 15°C, heat loss was facilitated by vasodilation of feet and wing membranes, but this mechanism became less effective at high Ta when thermal differential between wings and air was reduced. Bats are apparently unable to increase greatly their respiratory evaporation, and overheated at Ta of 25–30°C. At low Ta) the flight ability of two bats was reduced, suggesting that reduced coordination or even freezing of wings might be a general problem for bats flying at Ta close to 0°C. The endurance of three bats was so much greater near the middle of their speed ranges that the maximum flight distances ought to be achieved at these velocities, even though the cost of transport would be lower at higher speeds. Endurance at an airspeed was proportional to the relative power input (Pi/Pi,min) raised to the power of −7.45; flying at a speed that raised Pi/Pi,min by 10% reduced endurance by half.

scholarly journals Relations between morphology, buoyancy and energetics of requiem sharks

2016 ◽  
Vol 3 (10) ◽  
pp. 160406 ◽  
Author(s):  
Gil Iosilevskii ◽  
Yannis P. Papastamatiou
Keyword(s):  
Body Temperature ◽  
Negative Selection ◽  
Swimming Performance ◽  
Ontogenetic Changes ◽  
Cost Of Transport ◽  
Pectoral Fins ◽  
Confined Spaces ◽  
Reef Sharks ◽  
The Cost ◽  
Derivatives Of

Sharks have a distinctive shape that remained practically unchanged through hundreds of millions of years of evolution. Nonetheless, there are variations of this shape that vary between and within species. We attempt to explain these variations by examining the partial derivatives of the cost of transport of a generic shark with respect to buoyancy, span and chord of its pectoral fins, length, girth and body temperature. Our analysis predicts an intricate relation between these parameters, suggesting that ectothermic species residing in cooler temperatures must either have longer pectoral fins and/or be more buoyant in order to maintain swimming performance. It also suggests that, in general, the buoyancy must increase with size, and therefore, there must be ontogenetic changes within a species, with individuals getting more buoyant as they grow. Pelagic species seem to have near optimally sized fins (which minimize the cost of transport), but the majority of reef sharks could have reduced the cost of transport by increasing the size of their fins. The fact that they do not implies negative selection, probably owing to decreased manoeuvrability in confined spaces (e.g. foraging on a reef).

New Evolutionary Algorithm Based on 2-Opt Local Search to Solve the Vehicle Routing Problem with Private Fleet and Common Carrier

2012 ◽  
pp. 125-148
Author(s):  
Jalel Euchi ◽  
Habib Chabchoub ◽  
Adnan Yassine
Keyword(s):  
Local Search ◽  
Evolutionary Algorithm ◽  
Vehicle Routing ◽  
Cost Savings ◽  
Alternative Mode ◽  
Cost Of Transport ◽  
Routing Problem ◽  
The Cost ◽  
Specific Assignment ◽  
Selection Of

Mismanagement of routing and deliveries between sites of the same company or toward external sites leads to consequences in the cost of transport. When shipping alternatives exist, the selection of the appropriate shipping alternative (mode) for each shipment may result in significant cost savings. In this paper, the authors examine a class of vehicle routing in which a fixed internal fleet is available at the warehouse in the presence of an external transporter. The authors describe hybrid Iterated Density Estimation Evolutionary Algorithm with 2-opt local search to determine the specific assignment of each tour to a private vehicle (internal fleet) or an outside carrier (external fleet). Experimental results show that this method is effective, allowing the discovery of new best solutions for well-known benchmarks.

scholarly journals Soaring Flight in the Eleonora's Falcon (Falco eleonorae)

The Auk ◽  
2002 ◽  
Vol 119 (3) ◽  
pp. 835-840 ◽  
Author(s):  
Mikael Rosén ◽  
Anders Hedenström
Keyword(s):  
Flight Behavior ◽  
Small Island ◽  
Cost Of Transport ◽  
Open Sea ◽  
Gliding Flight ◽  
Eleonora’S Falcon ◽  
Soaring Flight ◽  
Falco Eleonorae ◽  
Vertical Winds ◽  
The Cost

Abstract Eleonora's Falcon (Falco eleonorae) breeds in the Mediterranean region and is highly adapted for catching small birds on passage migration between Eurasia and their African winter quarters, which they feed their young. We studied gliding flight behavior of Eleonora's Falcon at a breeding colony located on a small island southwest of Sardinia, Italy. Gliding and soaring flight performance was measured using an optical range finder and evaluated against flight mechanical theory. The male falcon does the majority of hunting and usually sets off from the colony to hunting areas located at high altitude over the open sea to catch prey. To lower the cost of transport and maximize the energy gain from hunting, we show that the birds use vertical winds for soaring when available. The occurrence of rising air changes with wind direction. At north-northwesterly winds (on-shore), slope lift is available outside the nesting cliffs, and at south-southeasterly winds thermals that form over the island drift out over the sea. Our observations demonstrated the flexibility of flight behavior in relation to the wind situation, and birds thereby make full use of available soaring conditions.

scholarly journals The rising cost of warming waters: effects of temperature on the cost of swimming in fishes

2011 ◽  
Vol 8 (2) ◽  
pp. 266-269 ◽  
Author(s):  
Andrew M. Hein ◽  
Katrina J. Keirsted
Keyword(s):  
Water Temperature ◽  
Fish Species ◽  
Global Climate ◽  
Swimming Performance ◽  
Metabolic Cost ◽  
Quantitative Model ◽  
The Body ◽  
Energetic Cost ◽  
Cost Of Transport ◽  
The Cost

Understanding the effects of water temperature on the swimming performance of fishes is central in understanding how fish species will respond to global climate change. Metabolic cost of transport (COT)—a measure of the energy required to swim a given distance—is a key performance parameter linked to many aspects of fish life history. We develop a quantitative model to predict the effect of water temperature on COT. The model facilitates comparisons among species that differ in body size by incorporating the body mass-dependence of COT. Data from 22 fish species support the temperature and mass dependencies of COT predicted by our model, and demonstrate that modest differences in water temperature can result in substantial differences in the energetic cost of swimming.

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