Fat storage influences fasting endurance more than body size in an ungulate
The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food restricted environment, but contrary to predictions from the FEH, empirical...
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Online Access: | https://hdl.handle.net/11250/2778599 https://doi.org/10.1111/1365-2435.13816 |
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ftunivmob:oai:nmbu.brage.unit.no:11250/2778599 2023-05-15T14:58:06+02:00 Fat storage influences fasting endurance more than body size in an ungulate Trondrud, Liv Monica Pigeon, Gabriel Król, Elżbieta Albon, Steve Evans, Alina Arnold, Walter Hambly, Catherine Irvine, R. Justin Ropstad, Erik Stien, Audun Veiberg, Vebjørn Speakman, John R. Loe, Leif Egil 2021-04-29T10:07:01Z application/pdf https://hdl.handle.net/11250/2778599 https://doi.org/10.1111/1365-2435.13816 eng eng Norges forskningsråd: 267613 Egen institusjon: NMBU urn:issn:0269-8463 https://hdl.handle.net/11250/2778599 https://doi.org/10.1111/1365-2435.13816 cristin:1907151 Functional Ecology VDP::Økologi: 488 VDP::Ecology: 488 Peer reviewed Journal article 2021 ftunivmob https://doi.org/10.1111/1365-2435.13816 2021-09-23T20:15:19Z The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food restricted environment, but contrary to predictions from the FEH, empirical evidence shows that Arctic mammals are often smaller than their temperate conspecifics. Intraspecific studies integrating physiology and behaviour of different‐sized individuals, may shed light on this paradox. We tested the FEH in free‐living Svalbard reindeer (Rangifer tarandus platyrhynchus). We measured daily energy expenditure (DEE), subcutaneous body temperature (Tsc) and activity levels during the late winter in 14 adult females with body masses ranging from 46.3 to 57.8 kg. Winter energy expenditure (WEE) and fasting endurance (FE) were modelled dynamically by combining these data with body composition measurements of culled individuals at the onset of winter (14 years, n = 140) and variation in activity level throughout winter (10 years, n = 70). Mean DEE was 6.3±0.7 MJ day−1. Lean mass, Tsc and activity had significantly positive effects on DEE. Across all 140 individuals, mean FE was 85±17 days (range 48–137 days). In contrast to the predictions of the FEH, the dominant factor affecting FE was initial fat mass, while body mass and FE were not correlated. Furthermore, lean mass and fat mass were not correlated. FE was on average 80% (45 days) longer in fat than lean individuals of the same size. Reducing activity levels by ~16% or Tsc by ~5% increased FE by 7%, and 4%, respectively. Our results fail to support the FEH. Rather, we demonstrate that (i) the size of fat reserves can be independent of lean mass and body size within a species, (ii) ecological and environmental variation influence FE via their effects on body composition, and (iii) physiological and behavioural adjustments can improve FE within individuals. Altogether, our results suggest that there is a selection in Svalbard reindeer to accumulate body fat, rather than to grow structurally large. he Arctic, activity, biologging, daily energy expenditure, doubly labelled water, intraspecific scaling, subcutaneous body temperature, Svalbard reindeer publishedVersion Article in Journal/Newspaper Arctic Rangifer tarandus Rangifer tarandus platyrhynchus Svalbard svalbard reindeer Open archive Norwegian University of Life Sciences: Brage NMBU Arctic Svalbard Dee ENVELOPE(-59.767,-59.767,-62.433,-62.433) Functional Ecology 35 7 1470 1480 |
institution |
Open Polar |
collection |
Open archive Norwegian University of Life Sciences: Brage NMBU |
op_collection_id |
ftunivmob |
language |
English |
topic |
VDP::Økologi: 488 VDP::Ecology: 488 |
spellingShingle |
VDP::Økologi: 488 VDP::Ecology: 488 Trondrud, Liv Monica Pigeon, Gabriel Król, Elżbieta Albon, Steve Evans, Alina Arnold, Walter Hambly, Catherine Irvine, R. Justin Ropstad, Erik Stien, Audun Veiberg, Vebjørn Speakman, John R. Loe, Leif Egil Fat storage influences fasting endurance more than body size in an ungulate |
topic_facet |
VDP::Økologi: 488 VDP::Ecology: 488 |
description |
The fasting endurance hypothesis (FEH) predicts strong selection for large body size in mammals living in environments where food supply is interrupted over prolonged periods of time. The Arctic is a highly seasonal and food restricted environment, but contrary to predictions from the FEH, empirical evidence shows that Arctic mammals are often smaller than their temperate conspecifics. Intraspecific studies integrating physiology and behaviour of different‐sized individuals, may shed light on this paradox. We tested the FEH in free‐living Svalbard reindeer (Rangifer tarandus platyrhynchus). We measured daily energy expenditure (DEE), subcutaneous body temperature (Tsc) and activity levels during the late winter in 14 adult females with body masses ranging from 46.3 to 57.8 kg. Winter energy expenditure (WEE) and fasting endurance (FE) were modelled dynamically by combining these data with body composition measurements of culled individuals at the onset of winter (14 years, n = 140) and variation in activity level throughout winter (10 years, n = 70). Mean DEE was 6.3±0.7 MJ day−1. Lean mass, Tsc and activity had significantly positive effects on DEE. Across all 140 individuals, mean FE was 85±17 days (range 48–137 days). In contrast to the predictions of the FEH, the dominant factor affecting FE was initial fat mass, while body mass and FE were not correlated. Furthermore, lean mass and fat mass were not correlated. FE was on average 80% (45 days) longer in fat than lean individuals of the same size. Reducing activity levels by ~16% or Tsc by ~5% increased FE by 7%, and 4%, respectively. Our results fail to support the FEH. Rather, we demonstrate that (i) the size of fat reserves can be independent of lean mass and body size within a species, (ii) ecological and environmental variation influence FE via their effects on body composition, and (iii) physiological and behavioural adjustments can improve FE within individuals. Altogether, our results suggest that there is a selection in Svalbard reindeer to accumulate body fat, rather than to grow structurally large. he Arctic, activity, biologging, daily energy expenditure, doubly labelled water, intraspecific scaling, subcutaneous body temperature, Svalbard reindeer publishedVersion |
format |
Article in Journal/Newspaper |
author |
Trondrud, Liv Monica Pigeon, Gabriel Król, Elżbieta Albon, Steve Evans, Alina Arnold, Walter Hambly, Catherine Irvine, R. Justin Ropstad, Erik Stien, Audun Veiberg, Vebjørn Speakman, John R. Loe, Leif Egil |
author_facet |
Trondrud, Liv Monica Pigeon, Gabriel Król, Elżbieta Albon, Steve Evans, Alina Arnold, Walter Hambly, Catherine Irvine, R. Justin Ropstad, Erik Stien, Audun Veiberg, Vebjørn Speakman, John R. Loe, Leif Egil |
author_sort |
Trondrud, Liv Monica |
title |
Fat storage influences fasting endurance more than body size in an ungulate |
title_short |
Fat storage influences fasting endurance more than body size in an ungulate |
title_full |
Fat storage influences fasting endurance more than body size in an ungulate |
title_fullStr |
Fat storage influences fasting endurance more than body size in an ungulate |
title_full_unstemmed |
Fat storage influences fasting endurance more than body size in an ungulate |
title_sort |
fat storage influences fasting endurance more than body size in an ungulate |
publishDate |
2021 |
url |
https://hdl.handle.net/11250/2778599 https://doi.org/10.1111/1365-2435.13816 |
long_lat |
ENVELOPE(-59.767,-59.767,-62.433,-62.433) |
geographic |
Arctic Svalbard Dee |
geographic_facet |
Arctic Svalbard Dee |
genre |
Arctic Rangifer tarandus Rangifer tarandus platyrhynchus Svalbard svalbard reindeer |
genre_facet |
Arctic Rangifer tarandus Rangifer tarandus platyrhynchus Svalbard svalbard reindeer |
op_source |
Functional Ecology |
op_relation |
Norges forskningsråd: 267613 Egen institusjon: NMBU urn:issn:0269-8463 https://hdl.handle.net/11250/2778599 https://doi.org/10.1111/1365-2435.13816 cristin:1907151 |
op_doi |
https://doi.org/10.1111/1365-2435.13816 |
container_title |
Functional Ecology |
container_volume |
35 |
container_issue |
7 |
container_start_page |
1470 |
op_container_end_page |
1480 |
_version_ |
1766330195121274880 |