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Watts HE, Cornelius JM. Toward understanding the endocrine regulation of diverse facultative migration strategies. Horm Behav 2024; 158:105465. [PMID: 38061233 DOI: 10.1016/j.yhbeh.2023.105465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 02/05/2024]
Abstract
Migration is an important event in the annual cycle of many animals that facilitates the use of resources that vary across space and time. It can occur with regular and predictable timing, as in obligate migration, or with much greater flexibility, as in facultative migration. Most research aimed at understanding the endocrine mechanisms regulating the transition to a migratory stage has focused on obligate migration, whereas less is known about facultative forms of migration. One challenge for research into the endocrine regulation of facultative migration is that facultative migrations encompass a diverse array of migratory movements. Here, we present a framework to describe and conceptualize variation in facultative migrations that focuses on conditions at departure. Within the context of this framework, we review potential endocrine mechanisms involved in the initiation of facultative migrations in vertebrates. We first focus on glucocorticoids, which have been the subject of most research on the topic. We then examine other potential hormones and neurohormones that have received less attention, but are exciting candidates to consider. We conclude by highlighting areas where future research is particularly needed.
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Affiliation(s)
- Heather E Watts
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA; Center for Reproductive Biology, Washington State University, Pullman, WA 99164, USA.
| | - Jamie M Cornelius
- Department of Integrative Biology, Oregon State University, Corvallis, OR 97331, USA
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2
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Ryan TA, Taff CC, Zimmer C, Vitousek MN. Cold temperatures induce priming of the glucose stress response in tree swallows. Comp Biochem Physiol A Mol Integr Physiol 2023; 280:111419. [PMID: 36965830 DOI: 10.1016/j.cbpa.2023.111419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/06/2023] [Accepted: 03/21/2023] [Indexed: 03/27/2023]
Abstract
Capricious environments often present wild animals with challenges that coincide or occur in sequence. Conceptual models of the stress response predict that one threat may prime or dampen the response to another. Although evidence has supported this for glucocorticoid responses, much less is known about the effects of previous challenges on energy mobilization. Food limitation may have a particularly important effect, by altering the ability to mobilize energy when faced with a subsequent challenge. We tested the prediction that challenging weather conditions, which reduce food availability, alter the energetic response to a subsequent acute challenge (capture and restraint). Using a three-year dataset from female tree swallows measured during three substages of breeding, we used a model comparison approach to test if weather (temperature, wind speed, and precipitation) over 3- or 72-hour timescales predicted baseline and post-restraint glucose levels, and if so which environmental factors were the strongest predictors. Contrary to our predictions, weather conditions did not affect baseline glucose; however, birds that had experienced lower temperatures over the preceding 72 h tended to have higher stress-induced glucose when faced with an acute stressor. We also saw some support for an effect of rainfall on stress-induced glucose: around the time that eggs hatched, birds that had experienced more rainfall over the preceding 72 h mounted lower responses. Overall, we find support in a wild animal for the idea that the glucose stress response may be primed by exposure to prior challenges.
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Affiliation(s)
- Thomas A Ryan
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA; Cornell Lab of Ornithology, Ithaca, NY, USA.
| | - Conor C Taff
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA; Cornell Lab of Ornithology, Ithaca, NY, USA
| | - Cedric Zimmer
- Laboratory of Experimental and Comparative Ethology, University Sorbonne Paris Nord, Villetaneuse, France
| | - Maren N Vitousek
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, USA; Cornell Lab of Ornithology, Ithaca, NY, USA
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3
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Freeman NE, Gustafson M, Hefley TJ, Boyle WA. Riding out the storm: depleted fat stores and elevated hematocrit in a small bodied endotherm exposed to severe weather. CONSERVATION PHYSIOLOGY 2023; 11:coad011. [PMID: 36950375 PMCID: PMC10026549 DOI: 10.1093/conphys/coad011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 02/15/2023] [Accepted: 03/14/2023] [Indexed: 06/18/2023]
Abstract
In the mid-continental grasslands of North America, climate change is increasing the intensity and frequency of extreme weather events. Increasingly severe storms and prolonged periods of elevated temperatures can impose challenges that adversely affect an individual's condition and, ultimately, survival. However, despite mounting evidence that extreme weather events, such as heavy rain storms, can impose short-term physiological challenges, we know little regarding the putative costs of such weather events. To determine the consequences of extreme weather for small endotherms, we tested predictions of the relationships between both severe precipitation events and wet bulb temperatures (an index that combines temperature and humidity) prior to capture with body composition and hematocrit of grasshopper sparrows (Ammodramus savannarum) caught during the breeding season at the Konza Prairie Biological Station, Kansas, USA, between 2014 and 2016. We measured each individual's fat mass, lean mass and total body water using quantitative magnetic resonance in addition to their hematocrit. Individuals exposed to storms in the 24 hours prior to capture had less fat reserves, more lean mass, more water and higher hematocrit than those exposed to moderate weather conditions. Furthermore, individuals stored more fat if they experienced high wet bulb temperatures in the week prior to capture. Overall, the analysis of these data indicate that extreme weather events take a physiological toll on small endotherms, and individuals may be forced to deplete fat stores and increase erythropoiesis to meet the physiological demands associated with surviving a storm. Elucidating the potential strategies used to cope with severe weather may enable us to understand the energetic consequences of increasingly severe weather in a changing world.
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Affiliation(s)
- N E Freeman
- Division of Biology, Kansas State University,
116 Ackert Hall, Manhattan, KS 66506, USA
- School of Natural Sciences, Bangor University,
Deiniol Road, Bangor, Gwynedd, LL57 2DG, UK
| | - M Gustafson
- Division of Biology, Kansas State University,
116 Ackert Hall, Manhattan, KS 66506, USA
- Department of Biological Sciences, Boise State University, 2133 Cesar Chavez Lane, Boise, ID 83725, USA
| | - T J Hefley
- Department of Statistics, Kansas State University, 101 Dickens Hall, Manhattan, KS 66506, USA
| | - W A Boyle
- Division of Biology, Kansas State University,
116 Ackert Hall, Manhattan, KS 66506, USA
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Integrating orientation mechanisms, adrenocortical activity, and endurance flight in vagrancy behaviour. Sci Rep 2022; 12:22104. [PMID: 36543804 PMCID: PMC9772197 DOI: 10.1038/s41598-022-26136-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 12/09/2022] [Indexed: 12/24/2022] Open
Abstract
Avian migratory processes are typically precisely oriented, yet vagrants are frequently recorded outside their normal range. Wind displaced vagrants often show corrective behaviour, and as an appropriate response is likely adaptive. We investigated the physiological response to vagrancy in passerines. Activation of the emergency life-history stage (ELHS), assessed by high baseline plasma corticosterone, is a potential mechanism to elicit compensatory behaviour in response to challenges resulting from navigational error, coupled with response to fuel load and flight. We compared circulating plasma corticosterone concentrations and body condition between three migratory groups in autumn: (1) wind displaced southwest (SW) vagrants and (2) long range southeast (SE) vagrants on the remote Faroe Islands, and (3) birds within the expected SW migratory route (controls) on the Falsterbo peninsula, Sweden. Vagrants were further grouped by those sampled immediately upon termination of over-water migratory flight and those already on the island. In all groups there was no indication of the activation of the ELHS in response to vagrancy. We found limited support for an increased rate of corticosterone elevation within our 3 min sample interval in a single species, but this was driven by an individual ELHS outlier. Fat scores were negatively correlated with circulating corticosterone; this relationship may suggest that ELHS activation depends upon an individual's energetic states. Interestingly, in individuals caught at the completion of an obligate long-distance flight, we found some evidence of corticosterone suppression. Although limited, data did support the induction of negative feedback mechanisms that suppress corticosterone during endurance exercise, even when fuel loads are low.
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Word KR, Austin SH, Wingfield JC. Allostasis revisited: A perception, variation, and risk framework. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.954708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The framework of allostasis, allostatic load and overload (i.e., stability through change) attempts to combine homeostasis processes in day-to-day responses of physiology and behavior. These include predictive changes in environment such as seasons, and facultative responses to perturbations. The latter can be severe, occur at any time, and may present considerable additional challenges to homeostasis. Hormonal cascades, such as the hypothalamo-pituitary-adrenal cortex (HPA) axis, play a key role in responses to perturbations across vertebrate taxa. Glucocorticoids have been implicated in these processes in relation to energy balance that plays a role in determining responses to energetic demand (allostatic load) and influencing subsequent physiology and behavior associated with coping. Circulating glucocorticoid levels are likely regulated in part based on an individual’s proximity to energetic crisis, identified as the perturbation resistance potential (PRP). In the model of allostatic load, PRP is quantified as the difference between available resources and all energetic costs of allostatic load such as daily routines, life history stages (breeding, migration, molt and so on), and the impact of environmental perturbations. PRP can change gradually or abruptly and may be reflected by spikes in blood hormone levels. The pattern of individual responsiveness to PRP may vary and has specific implications for the activation of mineralocorticoid vs glucocorticoid-type receptors, hormone metabolizing enzymes and other downstream factors in target tissues. However, PRP is a difficult metric to measure. Here, we examine the variety of cues that animals may use to inform them about the status of their PRP and probability of energetic crisis. We consider (1) elevation in glucocorticoids as an endocrine “decision,” and (2) error management strategies in evaluating responsiveness to cues that may reflect or predict an impending energetic crisis. The potential for differential receptor activation as well as further integrative “decisions” to determine the diverse and sometimes contradictory effects of receptor activation and its downstream actions are important to the consideration of error management. This perspective offers insight into the basis of intra- and inter-individual variability in responsiveness and opens an avenue toward improving compatibility of the allostasis model with more classical views on “stress”.
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Vitousek MN, Houtz JL, Pipkin MA, Chang van Oordt DA, Hallinger KK, Uehling JJ, Zimmer C, Taff CC. Natural and experimental cold exposure in adulthood increase the sensitivity to future stressors in a free‐living songbird. Funct Ecol 2022. [DOI: 10.1111/1365-2435.14144] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Maren N. Vitousek
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
| | - Jennifer L. Houtz
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
| | - Monique A. Pipkin
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
| | - David A. Chang van Oordt
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
| | - Kelly K. Hallinger
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
- Department of Biology Albion College Albion MI USA
| | - Jennifer J. Uehling
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
| | - Cedric Zimmer
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Laboratoire d’Ethologie Expérimentale et Comparée, LEEC Université Sorbonne Paris Nord UR Villetaneuse France
| | - Conor C. Taff
- Department of Ecology and Evolutionary Biology Cornell University Ithaca NY USA
- Cornell Lab of Ornithology Ithaca NY USA
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Krause JS, Watkins T, Reid AMA, Cheah JC, Pérez JH, Bishop VR, Ramenofsky M, Wingfield JC, Meddle SL. Gene expression of sex steroid metabolizing enzymes and receptors in the skeletal muscle of migrant and resident subspecies of white-crowned sparrow (Zonotrichia leucophrys). Oecologia 2022; 199:549-562. [PMID: 35732927 DOI: 10.1007/s00442-022-05204-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 05/27/2022] [Indexed: 10/17/2022]
Abstract
Circulating sex steroid concentrations vary dramatically across the year in seasonally breeding animals. The ability of circulating sex steroids to effect muscle function can be modulated by changes in intracellular expression of steroid metabolizing enzymes (e.g., 5α-reductase type 2 and aromatase) and receptors. Together, these combined changes in plasma hormones, metabolizing enzymes and receptors allow for seasonally appropriate changes in skeletal muscle function. We tested the hypothesis that gene expression of sex steroid metabolizing enzymes and receptors would vary seasonally in skeletal muscle and these changes would differ between a migrant and resident life history strategy. We quantified annual changes in plasma testosterone and gene expression in pectoralis and gastrocnemius skeletal muscles using quantitative polymerase chain reaction (qPCR) in free-living migrant (Zonotrichia leucophrys gambelii) and resident (Z. l. nuttalli) subspecies of white-crowned sparrow during breeding, pre-basic molt, and wintering life history stages. Pectoralis muscle profile was largest in migrants during breeding, while residents maintained large muscle profiles year-round. Circulating testosterone peaked during breeding in both subspecies. Pectoralis muscle androgen receptor mRNA expression was lower in females of both subspecies during breeding. Estrogen receptor-α expression was higher in the pectoralis muscle, but not gastrocnemius, of residents throughout the annual cycle when compared to migrants. Pectoralis aromatase expression was higher in resident males compared to migrant males. No differences were observed for 5α-reductase 2. Between these two subspecies, patterns of plasma testosterone and androgen receptors appear to be conserved, however estrogen receptor gene expression appears to have diverged.
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Affiliation(s)
- Jesse S Krause
- Department of Biology, University of Nevada Reno, 1664 N. Virginia Street, Sarah Fleischmann 109, Reno, NV, 89557, USA. .,Department of Neurobiology Physiology Behavior, University of California, Davis, CA, 95616, USA.
| | - Trevor Watkins
- Department of Biology, University of Nevada Reno, 1664 N. Virginia Street, Sarah Fleischmann 109, Reno, NV, 89557, USA
| | - Angus M A Reid
- Institute of Genetics and Molecular Medicine, University of Edinburgh, Crewe Road South, Edinburgh, EH4 2XU, Scotland, UK.,The Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, Scotland, UK
| | - Jeffrey C Cheah
- Department of Neurobiology Physiology Behavior, University of California, Davis, CA, 95616, USA
| | - Jonathan H Pérez
- Department of Biology, University of South Alabama, Mobile, AL, 36688, USA
| | - Valerie R Bishop
- The Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, Scotland, UK
| | - Marilyn Ramenofsky
- Department of Neurobiology Physiology Behavior, University of California, Davis, CA, 95616, USA
| | - John C Wingfield
- Department of Neurobiology Physiology Behavior, University of California, Davis, CA, 95616, USA
| | - Simone L Meddle
- The Roslin Institute, University of Edinburgh, Midlothian, EH25 9RG, Scotland, UK
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Mikkelsen AJ, Lesmeister DB, O’Reilly KM, Dugger KM. Feather corticosterone reveals developmental challenges in a long‐term study of juvenile northern spotted owls. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13944] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ashlee J. Mikkelsen
- USDA Forest Service Pacific Northwest Research Station Corvallis OR USA
- Oregon Cooperative Fish and Wildlife Research Unit Department of Fisheries, Wildlife, and Conservation Sciences Oregon State University Corvallis OR USA
| | - Damon B. Lesmeister
- USDA Forest Service Pacific Northwest Research Station Corvallis OR USA
- Department of Fisheries, Wildlife, and Conservation Sciences Oregon State University Corvallis OR USA
| | | | - Katie M. Dugger
- U.S. Geological Survey Oregon Cooperative Fish and Wildlife Research Unit Department of Fisheries, Wildlife, and Conservation Sciences Oregon State University Corvallis OR USA
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MacDougall-Shackleton SA, Bonier F, Romero LM, Moore IT. Glucocorticoids and "Stress" Are Not Synonymous. Integr Org Biol 2019; 1:obz017. [PMID: 33791532 PMCID: PMC7671118 DOI: 10.1093/iob/obz017] [Citation(s) in RCA: 135] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Reference to glucocorticoids as “stress hormones” has been growing in prevalence in the literature, including in comparative and environmental endocrinology. Although glucocorticoids are elevated in response to a variety of stressors in vertebrate animals, the primary functions of glucocorticoids are not responding to stressors and they are only one component of complex suite of physiological and behavioral responses to stressors. Thus, the use of the short-hand phrase “stress hormone” can be misleading. Further, simply measuring glucocorticoids is not equivalent to measuring a stress response, nor is manipulating glucocorticoids equivalent to exposing an animal to a stressor. In this commentary we highlight the problems with using functional names for hormones, and of treating cortisol or corticosterone as synonymous with stress. We provide recommendations to add clarity to the presentation of research on this topic, and to avoid conflation of glucocorticoids with stressors and the stress response in the design of experiments.
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Affiliation(s)
| | - F Bonier
- Biology Department, Queen's University, Kingston, Ontario, Canada K7L 3N6
| | - L M Romero
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - I T Moore
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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