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A trade-off between perceived predation risk and energy conservation revealed by an immune challenge experiment

Nord, Andreas LU ; Sköld Chiriac, Sandra LU ; Hasselquist, Dennis LU and Nilsson, Jan-Åke LU (2014) In Oikos 123(9). p.1091-1100
Abstract
Energy is typically a limiting factor for animals during boreal zone winters, when low temperatures increase the cost of thermoregulation at the same times as short day-lengths and snow cover constrain foraging opportunities. Under these circumstances animals use a suite of behavioural and physiological adaptations to avoid overnight starvation. However, it is poorly understood how such strategies are affected by increased energy demands from other physiological systems. Thus, we used free-ranging blue tits (Cyanistes caeruleus L.) to test if competing demands for energy (here induced by a non-inflammatory, antibody-mediated immune challenge) would affect nocturnal body temperature (a predictor of energy expenditure in small animals) and... (More)
Energy is typically a limiting factor for animals during boreal zone winters, when low temperatures increase the cost of thermoregulation at the same times as short day-lengths and snow cover constrain foraging opportunities. Under these circumstances animals use a suite of behavioural and physiological adaptations to avoid overnight starvation. However, it is poorly understood how such strategies are affected by increased energy demands from other physiological systems. Thus, we used free-ranging blue tits (Cyanistes caeruleus L.) to test if competing demands for energy (here induced by a non-inflammatory, antibody-mediated immune challenge) would affect nocturnal body temperature (a predictor of energy expenditure in small animals) and energy-saving nest box roosting behaviour. We also assessed if the immune challenge incurred long-term survival costs. We found no evidence that body temperature regulation differed between immune-challenged and saline-injected birds. Nor did the immune challenge reduce survival to the next breeding season. However, old (second winter or older) immune-challenged birds continued roosting in nest boxes to a larger extent at the peak immune response, despite increased perceived predation risk induced by the preceding capture and immunization. In contrast, old control birds were less prone to roost in nest boxes after capture and saline injection. This difference was less pronounced in young (first winter) birds. We interpret the increased risk-taking behaviour in immune-challenged birds as a consequence of a higher need for exploiting the thermal benefits of nest box roosting to reduce energy loss. This suggests that resource deficiency might be a stronger predictor of overnight survival than the threat of nocturnal predation in this system. As such, our study provides insights into the classic trade-off between starvation and predation risk, in suggesting that priority is given to minimizing the risk of starvation in situations where both starvation and predation risks increase during cold winter nights. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Oikos
volume
123
issue
9
pages
1091 - 1100
publisher
Wiley-Blackwell
external identifiers
  • wos:000342753900008
  • scopus:84897216259
ISSN
1600-0706
DOI
10.1111/oik.01221
language
English
LU publication?
yes
id
9645489d-4f62-41e2-a70e-34b7ca0aed63 (old id 4693569)
date added to LUP
2014-10-02 15:54:18
date last changed
2017-11-19 03:12:55
@article{9645489d-4f62-41e2-a70e-34b7ca0aed63,
  abstract     = {Energy is typically a limiting factor for animals during boreal zone winters, when low temperatures increase the cost of thermoregulation at the same times as short day-lengths and snow cover constrain foraging opportunities. Under these circumstances animals use a suite of behavioural and physiological adaptations to avoid overnight starvation. However, it is poorly understood how such strategies are affected by increased energy demands from other physiological systems. Thus, we used free-ranging blue tits (Cyanistes caeruleus L.) to test if competing demands for energy (here induced by a non-inflammatory, antibody-mediated immune challenge) would affect nocturnal body temperature (a predictor of energy expenditure in small animals) and energy-saving nest box roosting behaviour. We also assessed if the immune challenge incurred long-term survival costs. We found no evidence that body temperature regulation differed between immune-challenged and saline-injected birds. Nor did the immune challenge reduce survival to the next breeding season. However, old (second winter or older) immune-challenged birds continued roosting in nest boxes to a larger extent at the peak immune response, despite increased perceived predation risk induced by the preceding capture and immunization. In contrast, old control birds were less prone to roost in nest boxes after capture and saline injection. This difference was less pronounced in young (first winter) birds. We interpret the increased risk-taking behaviour in immune-challenged birds as a consequence of a higher need for exploiting the thermal benefits of nest box roosting to reduce energy loss. This suggests that resource deficiency might be a stronger predictor of overnight survival than the threat of nocturnal predation in this system. As such, our study provides insights into the classic trade-off between starvation and predation risk, in suggesting that priority is given to minimizing the risk of starvation in situations where both starvation and predation risks increase during cold winter nights.},
  author       = {Nord, Andreas and Sköld Chiriac, Sandra and Hasselquist, Dennis and Nilsson, Jan-Åke},
  issn         = {1600-0706},
  language     = {eng},
  number       = {9},
  pages        = {1091--1100},
  publisher    = {Wiley-Blackwell},
  series       = {Oikos},
  title        = {A trade-off between perceived predation risk and energy conservation revealed by an immune challenge experiment},
  url          = {http://dx.doi.org/10.1111/oik.01221},
  volume       = {123},
  year         = {2014},
}