Fat or lean: adjustment of endogenous energy stores to predictable and unpredictable changes in allostatic load

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

  • Jannik Schultner
  • Alexander S. Kitaysky
  • Jorg Welcker
  • Scott Hatch

The ability to store energy endogenously is an important ecological mechanism that allows animals to buffer predictable and unpredictable variation in allostatic load. The secretion of glucocorticoids, which reflects changes in allostatic load, is suggested to play a major role in the adjustment of endogenous stores to these varying conditions. Although crucially important, the relationship between allostatic load and energy stores remains largely unexplorTwo contrasting hypotheses describe how stores may be adjusted: animals may use low allostatic loads to increase stores to a maximum possible ('fat and fit'), or they can attain a lean physique due to fitness advantages of a low body mass ('lean and fit'). We compiled observational and experimental data available for a long-lived seabird to examine the relationship between glucocorticoids and stored energy at two life history stages (incubation and chick-rearing). Data were collected across multiple years and colonies in the North Pacific, thereby reflecting the wide range of environmental conditions birds' encounter in the marine environment. During experimental manipulations, allostatic load was minimized by supplementing food to free-living birds. We found that the relationship between allostatic load and energy stores was clearly curvilinear at both life history stages. Observational data suggested that energy stores remained relatively stable under low allostatic load and decreased under high loads. Experimental data showed that birds did not maximize energy stores under favourable conditions but maintained energy stores below a physiologically attainable level. Energy stores remained consistently lower during chick-rearing compared to incubation across the wide range of variations in allostatic load suggesting that stage-specific trade-offs limit the accumulation of energy during favourable environmental conditions. Secretion of glucocorticoids did not appear to mediate this shift in energy stores between the life history stages. Overall, results of this study support the 'lean and fit' hypothesis. We conclude that increased energy stores may not necessarily reflect better environmental conditions experienced by individuals or predict their higher fitness. A major advantage of adopting a lean physique when environmental conditions allow may be the avoidance of additional energetic costs for moving a heavy body. In breeding seabirds, this advantage may be more important during chick-rearing. In the focal species, the secretion of glucocorticoids might be involved in regulation of energy stores within a life history stage but does not appear to mediate an adaptive shift in energy stores between the incubating and chick-rearing stages of reproduction.

Original languageEnglish
JournalFunctional Ecology
Volume27
Issue number1
Pages (from-to)45-55
Number of pages11
ISSN0269-8463
DOIs
Publication statusPublished - 02.2013

    Research areas

  • allostasis, anorexia, baseline corticosterone, body condition, environmental conditions, fitness, food stress, life history, trade-offs, wing loading
  • Ecosystems Research

Recently viewed

Publications

  1. Construal level theory
  2. Effects of different video- or text-based reflection stimuli on pre-service teachers’ emotions, immersion, cognitive load and knowledge-based reasoning
  3. Multilevel Water Governance and Problems of Scale
  4. The interaction of precipitation and deformation in a binary Mg-Ca alloy at elevated temperatures
  5. Emotions and multimedia learning
  6. Disciplines and Doubts
  7. Das Alltagsmedium Blatt
  8. Evaluationbedarf des § 650c BGB
  9. Experimental and numerical analysis of material flow in porthole die extrusion
  10. Handbook of Philosophy of Management
  11. Monitoring of methotrexate chlorination in water
  12. Beyond the Network
  13. What explains the performance of participatory governance?
  14. Illegal Migration in Postfordism
  15. Guest editorial
  16. Conceptualizing sustainable consumption
  17. Acknowledging temporal diversity in sustainability transformations at the nexus of interconnected systems
  18. Transcending the Locality of Grassroots Initiatives
  19. The role of knowledge and information in innovation
  20. Internet-Based Cognitive Behavioral Therapy for Insomnia
  21. Applying the principles of green engineering to cradle-to-cradle design
  22. Geschlechtsneutralität
  23. Resisting foundations
  24. How to measure the substantive representation of traditionally excluded groups in comparative research
  25. “From Within Fur and Feathers”
  26. Welcome home! Introducing SocSES
  27. New incremental methods for springback compensation by stress superposition
  28. Lagrangian perspectives on turbulent superstructures in Rayleigh-Bénard convection
  29. Logistical futures the chinese dream, debordering labor, and migration
  30. Patterns of organizational (sub)culture and their influence on organizational effectiveness
  31. Indigenous and local knowledge in biocultural approaches to sustainability:
  32. Two high-mountain burnet moth species (Lepidoptera, Zygaenidae) react differently to the global change drivers climate and land-use
  33. Textkommentierungen
  34. Pathways for Transformation
  35. The Basic Values of Russian and European Schoolteachers
  36. Don't ignore the floor
  37. The Folding of the American Working Class in Mad Men
  38. Circularity in green chemical products, processes and services
  39. Comprehensive meta-analysis of excess mortality in depression in the general community versus patients with specific illnesses.
  40. Qualitätsentwicklung und Qualitätssicherung in der Schreibzentrumsarbeit
  41. "Stürmische Plötzlichkeiten"