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Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation

Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation
Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation
Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species’ vulnerability to climate warming and extreme events.
macrophysiology, operative temperature, climate sensitivity
0027-8424
5610-5615
Sunday, Jennifer M.
825c86f3-1fd5-45ad-a08d-804535daadf9
Bates, Amanda E.
a96e267d-6d22-4232-b7ed-ce4e448a2a34
Kearney, Michael R.
61bf94df-7e97-41a8-a9e4-87861f527060
Colwell, Robert K.
8a9fa14f-6577-4027-84b9-d1ee6b723905
Dulvy, Nicholas K.
c514f298-ee3d-40b9-8ffb-1ec56d8f8e38
Longino, John T.
84b96c70-c77f-42e8-a20a-53508903c614
Huey, Raymond B.
1d4fa984-393a-41b0-94c9-bb4983db8945
Sunday, Jennifer M.
825c86f3-1fd5-45ad-a08d-804535daadf9
Bates, Amanda E.
a96e267d-6d22-4232-b7ed-ce4e448a2a34
Kearney, Michael R.
61bf94df-7e97-41a8-a9e4-87861f527060
Colwell, Robert K.
8a9fa14f-6577-4027-84b9-d1ee6b723905
Dulvy, Nicholas K.
c514f298-ee3d-40b9-8ffb-1ec56d8f8e38
Longino, John T.
84b96c70-c77f-42e8-a20a-53508903c614
Huey, Raymond B.
1d4fa984-393a-41b0-94c9-bb4983db8945

Sunday, Jennifer M., Bates, Amanda E., Kearney, Michael R., Colwell, Robert K., Dulvy, Nicholas K., Longino, John T. and Huey, Raymond B. (2014) Thermal-safety margins and the necessity of thermoregulatory behavior across latitude and elevation. Proceedings of the National Academy of Sciences, 111 (15), 5610-5615. (doi:10.1073/pnas.1316145111).

Record type: Article

Abstract

Physiological thermal-tolerance limits of terrestrial ectotherms often exceed local air temperatures, implying a high degree of thermal safety (an excess of warm or cold thermal tolerance). However, air temperatures can be very different from the equilibrium body temperature of an individual ectotherm. Here, we compile thermal-tolerance limits of ectotherms across a wide range of latitudes and elevations and compare these thermal limits both to air and to operative body temperatures (theoretically equilibrated body temperatures) of small ectothermic animals during the warmest and coldest times of the year. We show that extreme operative body temperatures in exposed habitats match or exceed the physiological thermal limits of most ectotherms. Therefore, contrary to previous findings using air temperatures, most ectotherms do not have a physiological thermal-safety margin. They must therefore rely on behavior to avoid overheating during the warmest times, especially in the lowland tropics. Likewise, species living at temperate latitudes and in alpine habitats must retreat to avoid lethal cold exposure. Behavioral plasticity of habitat use and the energetic consequences of thermal retreats are therefore critical aspects of species’ vulnerability to climate warming and extreme events.

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More information

e-pub ahead of print date: 3 February 2014
Published date: 15 April 2014
Keywords: macrophysiology, operative temperature, climate sensitivity
Organisations: Ocean and Earth Science

Identifiers

Local EPrints ID: 363028
URI: http://eprints.soton.ac.uk/id/eprint/363028
ISSN: 0027-8424
PURE UUID: 59edff8c-0f91-4c10-aa19-aa5ebd029fdd

Catalogue record

Date deposited: 12 Mar 2014 10:06
Last modified: 16 Jul 2019 21:10

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