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Conversion efficiency of flight power is low, but increases with flight speed in the migratory bat Pipistrellus nathusii

Currie, Shannon E. LU ; Johansson, L. Christoffer LU ; Aumont, Cedric LU ; Voigt, Christian C. and Hedenström, Anders LU (2023) In Proceedings of the Royal Society B: Biological Sciences 290(1998).
Abstract

The efficiency with which flying animals convert metabolic power to mechanical power dictates an individual's flight behaviour and energy requirements. Despite the significance of this parameter, we lack empirical data on conversion efficiency for most species as in vivo measurements are notoriously difficult to obtain. Furthermore, conversion efficiency is often assumed to be constant across flight speeds, even though the components driving flight power are speed-dependent. We show, through direct measurements of metabolic and aerodynamic power, that conversion efficiency in the migratory bat (Pipistrellus nathusii) increases from 7.0 to 10.4% with flight speed. Our findings suggest that peak conversion efficiency in this species... (More)

The efficiency with which flying animals convert metabolic power to mechanical power dictates an individual's flight behaviour and energy requirements. Despite the significance of this parameter, we lack empirical data on conversion efficiency for most species as in vivo measurements are notoriously difficult to obtain. Furthermore, conversion efficiency is often assumed to be constant across flight speeds, even though the components driving flight power are speed-dependent. We show, through direct measurements of metabolic and aerodynamic power, that conversion efficiency in the migratory bat (Pipistrellus nathusii) increases from 7.0 to 10.4% with flight speed. Our findings suggest that peak conversion efficiency in this species occurs near maximum range speed, where the cost of transport is minimized. A meta-analysis of 16 bird and 8 bat species revealed a positive scaling relationship between estimated conversion efficiency and body mass, with no discernible differences between bats and birds. This has profound consequences for modelling flight behaviour as estimates assuming 23% efficiency underestimate metabolic costs for P. nathusii by almost 50% on average (36-62%). Our findings suggest that conversion efficiency may vary around an ecologically relevant optimum speed and provide a crucial baseline for investigating whether this drives variation in conversion efficiency between species.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
13 C-labelled sodium bicarbonate, energy efficiency, mechanical power output, metabolic power input, particle image velocimetry, wind tunnel
in
Proceedings of the Royal Society B: Biological Sciences
volume
290
issue
1998
article number
20230045
pages
11 pages
publisher
Royal Society Publishing
external identifiers
  • pmid:37132234
  • scopus:85158002631
ISSN
0962-8452
DOI
10.1098/rspb.2023.0045
language
English
LU publication?
yes
id
a6ebc782-2960-473e-8dab-2b274a7e2cef
date added to LUP
2023-08-10 12:57:53
date last changed
2024-04-20 01:19:44
@article{a6ebc782-2960-473e-8dab-2b274a7e2cef,
  abstract     = {{<p>The efficiency with which flying animals convert metabolic power to mechanical power dictates an individual's flight behaviour and energy requirements. Despite the significance of this parameter, we lack empirical data on conversion efficiency for most species as in vivo measurements are notoriously difficult to obtain. Furthermore, conversion efficiency is often assumed to be constant across flight speeds, even though the components driving flight power are speed-dependent. We show, through direct measurements of metabolic and aerodynamic power, that conversion efficiency in the migratory bat (Pipistrellus nathusii) increases from 7.0 to 10.4% with flight speed. Our findings suggest that peak conversion efficiency in this species occurs near maximum range speed, where the cost of transport is minimized. A meta-analysis of 16 bird and 8 bat species revealed a positive scaling relationship between estimated conversion efficiency and body mass, with no discernible differences between bats and birds. This has profound consequences for modelling flight behaviour as estimates assuming 23% efficiency underestimate metabolic costs for P. nathusii by almost 50% on average (36-62%). Our findings suggest that conversion efficiency may vary around an ecologically relevant optimum speed and provide a crucial baseline for investigating whether this drives variation in conversion efficiency between species.</p>}},
  author       = {{Currie, Shannon E. and Johansson, L. Christoffer and Aumont, Cedric and Voigt, Christian C. and Hedenström, Anders}},
  issn         = {{0962-8452}},
  keywords     = {{13 C-labelled sodium bicarbonate; energy efficiency; mechanical power output; metabolic power input; particle image velocimetry; wind tunnel}},
  language     = {{eng}},
  month        = {{05}},
  number       = {{1998}},
  publisher    = {{Royal Society Publishing}},
  series       = {{Proceedings of the Royal Society B: Biological Sciences}},
  title        = {{Conversion efficiency of flight power is low, but increases with flight speed in the migratory bat Pipistrellus nathusii}},
  url          = {{http://dx.doi.org/10.1098/rspb.2023.0045}},
  doi          = {{10.1098/rspb.2023.0045}},
  volume       = {{290}},
  year         = {{2023}},
}