The influence of natural photoperiod on seasonal torpor expression of two opportunistic marsupial hibernators

James M. Turner, Fritz Geiser

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6 Citations (Scopus)

Abstract

Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months. Western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) used spontaneous torpor in every month of the year; in total we measured >1100 individual torpor bouts. Torpor bout duration was >60 % longer in winter than in summer and increased with decreasing day length for both species. Interestingly, the duration of torpor appeared to be adjusted at both the beginning and end of bouts because the time of entry into and rewarming from torpor relative to sunrise and sunset, respectively, changed with season. We propose that this reflects a synchronisation of torpor timing with foraging periods in the wild, which would enable animals to maintain a high body mass year-round by maximising both energy savings via torpor and energy input via food consumption. Our study suggests that photoperiod makes a significant contribution to the seasonal change in torpor bout duration of small hibernating mammals that use torpor throughout the year.
Original languageEnglish
Pages (from-to)375-383
Number of pages9
JournalJournal of Comparative Physiology B: biochemical, systemic, and environmental physiology
Volume187
Issue number2
DOIs
Publication statusPublished - Feb 2017

Cite this

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title = "The influence of natural photoperiod on seasonal torpor expression of two opportunistic marsupial hibernators",
abstract = "Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months. Western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) used spontaneous torpor in every month of the year; in total we measured >1100 individual torpor bouts. Torpor bout duration was >60 {\%} longer in winter than in summer and increased with decreasing day length for both species. Interestingly, the duration of torpor appeared to be adjusted at both the beginning and end of bouts because the time of entry into and rewarming from torpor relative to sunrise and sunset, respectively, changed with season. We propose that this reflects a synchronisation of torpor timing with foraging periods in the wild, which would enable animals to maintain a high body mass year-round by maximising both energy savings via torpor and energy input via food consumption. Our study suggests that photoperiod makes a significant contribution to the seasonal change in torpor bout duration of small hibernating mammals that use torpor throughout the year.",
keywords = "Burramyidae, Cercartetus spp., Environmental cue, Temporal organisation, Season, Non-invasive method",
author = "Turner, {James M.} and Fritz Geiser",
year = "2017",
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language = "English",
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pages = "375--383",
journal = "Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology",
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TY - JOUR

T1 - The influence of natural photoperiod on seasonal torpor expression of two opportunistic marsupial hibernators

AU - Turner, James M.

AU - Geiser, Fritz

PY - 2017/2

Y1 - 2017/2

N2 - Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months. Western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) used spontaneous torpor in every month of the year; in total we measured >1100 individual torpor bouts. Torpor bout duration was >60 % longer in winter than in summer and increased with decreasing day length for both species. Interestingly, the duration of torpor appeared to be adjusted at both the beginning and end of bouts because the time of entry into and rewarming from torpor relative to sunrise and sunset, respectively, changed with season. We propose that this reflects a synchronisation of torpor timing with foraging periods in the wild, which would enable animals to maintain a high body mass year-round by maximising both energy savings via torpor and energy input via food consumption. Our study suggests that photoperiod makes a significant contribution to the seasonal change in torpor bout duration of small hibernating mammals that use torpor throughout the year.

AB - Many mammals use torpor throughout the year but the individual contributions of environmental variables to seasonal changes in torpor expression are often difficult to tease apart. In many mammals, torpor is most often used opportunistically in response to decreased ambient temperature (T a ) and food availability, but information on how seasonally changing photoperiod per se influences torpor patterns is scant. Therefore, we quantified patterns of torpor use in response to natural photoperiod in captive marsupial pygmy-possums held at near-constant T a with a stable food supply over a period of 19 months. Western pygmy-possums (Cercartetus concinnus) and eastern pygmy-possums (C. nanus) used spontaneous torpor in every month of the year; in total we measured >1100 individual torpor bouts. Torpor bout duration was >60 % longer in winter than in summer and increased with decreasing day length for both species. Interestingly, the duration of torpor appeared to be adjusted at both the beginning and end of bouts because the time of entry into and rewarming from torpor relative to sunrise and sunset, respectively, changed with season. We propose that this reflects a synchronisation of torpor timing with foraging periods in the wild, which would enable animals to maintain a high body mass year-round by maximising both energy savings via torpor and energy input via food consumption. Our study suggests that photoperiod makes a significant contribution to the seasonal change in torpor bout duration of small hibernating mammals that use torpor throughout the year.

KW - Burramyidae

KW - Cercartetus spp.

KW - Environmental cue

KW - Temporal organisation

KW - Season

KW - Non-invasive method

U2 - 10.1007/s00360-016-1031-z

DO - 10.1007/s00360-016-1031-z

M3 - Article

VL - 187

SP - 375

EP - 383

JO - Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology

JF - Journal of Comparative Physiology B: biochemical, systemic, and environmental physiology

SN - 0174-1578

IS - 2

ER -