Field Endocrinology Research Articles

Testing of Daubenton's Bat (Myotis daubentonii) Droppings for Field Behavioural Endocrinology

Measurement of faecal hormonal metabolites has become a widespread method in field endocrinology due to its non-invasiveness and ability to assess long-term stress; however, this approach has some limitations. We tested the potential of this assay for the Daubenton's bat (Myotis daubentonii), a small vespertilionid species (body mass 6–10 g), and we explored the relationship between cortisol and testosterone levels and dawn swarming, a signalling behaviour that occurs during roost-switching. Swarming was recorded using automated PIT-tag readers on the tree roosts of a maternity colony. In spite of absence of biological validation, our preliminary results demonstrate that field conditions of sample storage and small faeces weight do not interfere with hormonal measurement. We also found a positive correlation between individual levels of stress hormone (cortisol faecal metabolites) and swarming behaviour, but this should be interpreted with caution due to methodological shortcomings that need to be improved in future studies.

Evaluation of long-term 11-oxoaetiocholanolone stability in red deer faecal samples under different storage conditions

Faecal cortisol metabolite (FCM) analysis is a reliable non-invasive method used in field endocrinology studies to assess levels of stress in animals. It is known that weather and, above all, humidity, can affect FCM concentrations in faecal samples. In addition, the prolonged storage of samples and delay in their analysis may alter metabolite concentrations. Intrinsic factors such as the heterogeneous distribution of FCMs within scats may likewise cause intra-sample variation. All of these sources of variation in FCM concentrations need to be addressed if we are to interpret results correctly. The aim of this study was to assess the effects of lyophilisation and storage temperature on the long-term stability of 11-oxoaetiocholanolone (11-o) in red deer (Cervus elaphus) faecal samples. After pre-cleaning with hexane and extraction with methanol, 11-o levels were analysed using high-performance liquid chromatography coupled with tandem mass spectrometry HPLC-MS/MS at 1, 2, 4, 6, 8, 16 and 32 weeks post-collection. We used linear mixed models to explore the effects of temperature and storage time on concentrations of faecal 11-o in wet and dry samples. Our results showed significant variations in 11-o concentrations in wet faecal samples over time and at different storage temperatures. By contrast, the 11-o values of dry samples were more stable in terms of storage temperatures. Lyophilising red deer faecal samples and storage at − 80 °C guarantees the stability of 11-o for several months.

Non-invasive Methods for Measuring and Monitoring Stress Physiology in Imperiled Amphibians

Global climate change is negatively impacting global biodiversity and ectothermic vertebrates, with amphibians being the most imperiled vertebrate taxa. Increased mean global atmospheric temperatures, high rates of habitat degradation, and exposure to infectious diseases, such as chytridiomycosis, have contributed to population declines and extinctions of rare and endangered amphibian species. Field-based monitoring of physiological endocrine traits can help determine the sub-lethal effects of environmental stressors and provide early alerts when populations are chronically stressed. Recent advances in amphibian stress endocrinology include the development and use of non-invasive methods to quantify the glucocorticoid, or stress biomarker, corticosterone. Non-invasive methods, such as urinary, skin and buccal swabs, and water-borne hormone monitoring methods (suited for terrestrial and aquatic dwelling species), are available to quantify baseline and short-term physiological stress responses of amphibians under field settings. In this review, we illustrate, by using two case studies of aquatic and terrestrial amphibian species, the applications of non-invasive corticosterone monitoring methods to advance the ecological knowledge and conservation of imperiled amphibian species, discuss the limitations of these methods, and provide future directions for the use of non-invasive hormone monitoring methods. We highlight the use of non-invasive field endocrinology methods to monitor the impacts of environmental stressors on the physiology of amphibians, which can be applied to advance ecological research, conservation, and management of imperiled species.

A Mathematical Modeling Approach to the Cort-Fitness Hypothesis.

The Cort-Fitness Hypothesis has generated much interest from investigators integrating field endocrinology with evolutionary biology, ecology, and conservation. The hypothesis was developed to test the assumption that if glucocorticoid levels increase with environmental challenges and fitness decreases with environmental challenges, then there should be a negative relationship between baseline glucocorticoid levels and fitness. Indeed, studies across diverse taxa have found that the relationship between baseline glucocorticoid levels and fitness are not consistent: some studies show a positive relationship, others negative, and some show no correlation. Hence, a deeper understanding of the mechanisms underlying the relationship between baseline glucocorticoid levels, environmental challenges, and fitness is needed. We propose a mathematical model representing the links between baseline glucocorticoid levels, environmental challenges, and fitness. Our model describes how variation in the predictability and intensity of environmental challenges, reproductive strategies, and fitness metrics can all contribute to the variability observed in empirical tests of the Cort-Fitness Hypothesis. We provide qualitative results showing that much of the inconsistency in previous studies can be explained and we discuss how the model can be used to inform future Cort-Fitness studies.

Environmental Endocrinology: Insights into the Diversity of Regulatory Mechanisms in Life Cycles.

All organisms must time their life cycles appropriately and organize life history stages into temporal sequences that enhance fitness in a changing environment. The endocrine system plays a major regulatory role in transducing information from the environment into morphological, physiological, and behavioral responses appropriate for the time of year. The perception, transduction, response pathways via neural and endocrine mechanisms are beginning to be explored and underscore the critical regulatory roles they play. Whereas many conserved mechanisms (evolutionary constraints hypothesis) are emerging, there is a growing realization that there may be alternate pathways unique to populations and individuals (evolutionary flexibility hypothesis). Field investigations (field endocrinology) over the past 45 years have revealed patterns of hormonal responses to environmental changes, physical and social, that could not have been anticipated from laboratory investigations alone. These patterns include differences at population and individual levels that have enabled new insights into acclimation and adaptation to environmental transitions. The number of species studied under natural conditions has grown exponentially in recent years to include all vertebrate classes and some invertebrates as well. These data are now driving evolutionary perspectives and with the advent of comparative genomics a new and exciting era of evolutionary/ecological endocrinology is developing. This article gives a brief overview of where the field stands now and where it is likely to go in the future especially in relation to the networks of regulatory pathways and how they can be modulated to enable acclimation of individuals as well as populations. One illustrative example, mechanisms underlying modulation of the adrenocortical responses to environmental stress, is the focus of this communication. These "coping" mechanisms will be key for acclimation and adaptation to global change.

Sexual dimorphism in baseline urinary corticosterone metabolites and their association with body-condition indices in a peri-urban population of the common Asian toad (Duttaphrynus melanostictus)

Field endocrinology research through the quantification of glucocorticoids or stress hormones in free-living wildlife is crucial for assessing their physiological responses towards pervasive environmental changes. Urinary corticosterone metabolite (UCM) enzyme–immunoassay (EIA) has been validated for numerous amphibian species as a non-invasive measure of physiological stress. Body-condition indices (BCIs) have also been widely used in amphibians as an indirect measure of animal health. Field endocrinology research on amphibian species in Asia is limited. In this study, we validated a UCM EIA in a peri-urban sub-population of the common Asian toad (Duttaphrynus melanostictus) in Pune, Maharashtra, India. We determined the baseline levels of UCMs in male (n=39) and female (n=19) toads. Secondly, we used a standard capture handling protocol to quantify changes in UCMs during short-term captivity. We also determined BCIs in the male and female toads using Fulton's index (K) and residual condition index (RCI). The results showed that mean baseline levels of UCMs were significantly higher in male toads than in females. There was no significant change in mean levels of UCMs of males and females between capture and captivity (0–12h). This highlights plausible habituation of the species to the peri-urban environment. Associations between UCMs with BCIs (K and R) were positive in male toads but negative in females. In conclusion, our UCMs EIA can be applied with BCIs to assess health of the Asian toads. We also suggest that direct fitness parameters such as sperm and oocyte quality, reproductive ecology and immunocompetence measurements should be applied in combination with these conservation physiology tools to quantify the fitness consequences of pervasive environmental changes on native amphibians.

Oncofertility: Realizing a couples' dream of parenthood

Oncofertility is an emerging field, merging oncology and reproductive endocrinology. Any woman facing a cancer diagnosis is devastated especially if she is young. Young women diagnosed with cancer face an additional burden of compromise of future fertility. Oncofertility aims to explore and expand fertility options to address reproductive concerns of young women with cancer diagnosis. This review aims to highlight the available and emerging options for young women diagnosed with gynecological cancers to enable them to realize their dream of parenthood.

Long‐term storage effects in steroid metabolite extracts from baboon (Papio sp.) faeces – a comparison of three commonly applied storage methods

Summary The measurement of steroid hormone metabolites from faeces in wild animal populations is a powerful, noninvasive tool in behavioural endocrinology of all major vertebrate taxa. However, because such research is often done in remote areas with limited infrastructure, storage of samples for hormone analysis over long periods at high temperature is a critical issue in field endocrinology. Previous studies have indicated that storage of alcoholic faecal extracts is more reliable than storage of unprocessed faeces if no freezer is available, but a standard method has not been established yet. We tested the validity of three commonly applied storage conditions – liquid extracts, dried extracts and extracts placed on solid‐phase extraction (SPE) cartridges – to preserve concentrations of glucocorticoid and androgen metabolites from faecal extracts of olive baboons (Papio anubis) at high temperature over 1 year. Temporal variation in concentrations was detected for all metabolites and all storage conditions, including values measured from the control condition, that is, extracts stored at −20°C. This suggested that most variation was due to interassay variability, corroborated by comparisons of variation in ‘quality controls’ and samples. Compared to frozen control samples, liquid extracts were stable for up to 24 weeks, extracts on SPE cartridges were stable for up to 50 weeks, while steroid metabolite concentrations in dried extracts decreased slightly over time. If steroid samples have to be stored at ambient temperature, we suggest storage of liquid extracts for up to 24 weeks in a dark and cool place. For longer periods, SPE cartridges should be applied as evaporation, a potential confound arising with long‐term storage of liquid extracts at higher temperatures, is not a problem in this storage condition. Storage of dried extracts is more cost‐effective, but may result in small time‐dependent changes in steroid concentrations.

Evaluación de eventos reproductivos y estrés fisiológico en vertebrados silvestres a partir de sus excretas: evolución de una metodología no invasiva

Este documento tiene como objetivo servir como referencia de términos y procesos asociados a una metodología no invasiva para el estudio de la fisiología de vertebrados silvestre, pero también de las transformaciones históricas que dicha metodología ha experimentado. Debido a la dificultad de su encuentro directo y su manipulación, las investigaciones de vertebrados silvestres requieren, muchas veces, de aproximaciones indirectas. Un recurso tradicionalmente empleado es la recolección de muestras fecales en el campo que permite definición de distribución, abundancia, dieta e infestación parasitaria de especies de interés. Más recientemente, tomado de prácticas veterinarias utilizadas en zoológicos y granjas, el uso de heces se ha adoptado para evaluar concentraciones de hormonas. Durante los últimos 10-15 años, la endocrinología de campo ha aportado información sobre los ciclos reproductivos, cambios estacionales en concentraciones hormonales, diferencias sexuales y de comportamiento asociadas a las hormonas, asociación entre posiciones jerárquicas, estrés y concentraciones hormonales con efectos sobre la reproducción y, aún, efectos de las actividades humanas sobre el bienestar de especies silvestres. Sin embargo, la investigación de las técnicas de laboratorio asociadas a esta disciplina durante los últimos 3 años, llama a tener precaución con su uso y enfatiza la validación previa, especie por especie. Dado que el avance de esta línea de investigación requiere de protocolos de análisis adecuados y de preguntas sólidas sobre ecología de campo, la colaboración creativa de expertos de ambas áreas (los técnicos de laboratorio y los ecólogos de fauna silvestre), sería una práctica pertinente en países como México donde los recursos humanos y capitales son limitados.

Spatial and temporal dynamics of corticosterone and corticosterone binding globulin are driven by environmental heterogeneity

The question of whether changes in glucocorticoid concentrations reflect consistent changes in physiology associated with transitions between different stages of reproduction, or whether they reflect responses to environmental conditions, is one the central issues in field endocrinology studies. We examined the temporal and spatial dynamics of corticosterone (CORT, baseline, and acute stress-induced) and corticosterone binding globulin (CBG) concentrations in blood of Black-legged Kittiwakes (Rissa tridactyla) breeding at four major colonies in the Bering Sea, Alaska, during 1999–2005. We found that total CORT, free CORT, and CBG capacity varied inconsistently among reproductive stages, colonies, and years. Total CORT levels were positively correlated with CBG capacity. Variation in free CORT was largely driven by variation in total CORT. Results suggest that the adrenocortical function and CBG in breeding kittiwakes do not vary as a consequence of stage-specific modulation associated with a particular reproductive stage as in some short-lived passerine birds. Rather, in accord with predictions for a long-lived species, the lack of consistent colony, year, and reproductive stage patterns in baseline and maximum CORT, and CBG indicates that environmental factors, probably local dynamics of food availability, drive variation in these factors.

Stress hormones link food availability and population processes in seabirds

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 352:245-258 (2007) - DOI: https://doi.org/10.3354/meps07074 Stress hormones link food availability and population processes in seabirds A. S. Kitaysky1,*, J. F. Piatt2, J. C. Wingfield3 1Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, Alaska 99775, USA 2USGS Alaska Science Center, 1011 East Tudor Road, Anchorage, Alaska 99503, USA 3Department of Biology, University of Washington, Seattle, Washington 98195, USA *Email: ffask@uaf.edu ABSTRACT: Catastrophic population declines in marine top predators in the northern Pacific have been hypothesized to result from nutritional stress affecting reproduction and survival of individuals. However, empirical evidence for food-related stress in wild animals is frequently lacking or inconclusive. We used a field endocrinology approach to measure stress, identify its causes, and examine a link between stress and population processes in the common murre Uria aalge. We tested the empirical relationship between variations in the stress hormone corticosterone (CORT) and food abundance, reproduction, and persistence of individuals at declining and increasing colonies in Cook Inlet, Alaska, from 1996 to 2001. We found that CORT secretion in murres is independent of colony, reproductive stage effects, and gender of individuals, but is directly negatively correlated with abundance of their food. Baseline CORT reflected current food abundance, whereas acute stress-induced CORT reflected food abundance in the previous month. As food supply diminished, increased CORT secretion predicted a decrease in reproductive performance. At a declining colony, increased baseline levels of CORT during reproduction predicted disappearance of individuals from the population. Persistence of individuals in a growing colony was independent of CORT during reproduction. The obtained results support the hypothesis that nutritional stress during reproduction affects reproduction and survival in seabirds. This study provides the first unequivocal evidence for CORT secretion as a mechanistic link between fluctuations in food abundance and population processes in seabirds. KEY WORDS: Corticosterone · Food availability · Stress · Seabirds · Population processes Full text in pdf format PreviousNextCite this article as: Kitaysky AS, Piatt JF, Wingfield JC (2007) Stress hormones link food availability and population processes in seabirds. Mar Ecol Prog Ser 352:245-258. https://doi.org/10.3354/meps07074 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 352. Online publication date: December 20, 2007 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2007 Inter-Research.

Field Endocrinology and Conservation Biology

Field endocrinology techniques allow the collection of samples (i.e., blood, urine, feces, tissues) from free-living animals for analysis of hormones, receptors, enzymes, etc. These data reveal mechanisms by which individuals respond to environmental challenges, breed, migrate and regulate all aspects of their life cycles. Field endocrinology techniques can also be used to address many issues in conservation biology. We briefly review past and current ways in which endocrine methods are used to monitor threatened species, identify potential stressors and record responses to environmental disturbance. We then focus on one important aspect of conservation: how free-living populations respond to human disturbance, particularly in relation to ecotourism. Breeding adult Magellanic penguins, Spheniscus magellanicus, appear to habituate well to tourists, and breed in an area where about 70,000 people visit during the season. Baseline levels of corticosterone return to normal after exposure of naïve birds to humans. However, penguin chicks appear to show a heightened adrenocortical response to handling stress in nests exposed to tourists, compared to chicks living in areas isolated from human intrusions. Given that developmental exposure to stress can have profound influences on how individuals cope with stress as adults, this potential effect of tourists on chicks could have long-term consequences. This field endocrine approach identified a stressor not observed through monitoring behavior alone.

Concentrations of four fecal steroids in wild baboons: short-term storage conditions and consequences for data interpretation

One source of both bias and “noise” in fecal steroid analysis is temporal change in steroid concentrations resulting from duration or conditions of fecal sample storage. However, no consensus currently exists regarding correct procedures or precautions necessary for fecal sample storage, and conditions vary widely within field endocrinology literature. This study considered the effects of short-term, weeks-long, storage conditions on quantifiable fecal testosterone (fT), glucocorticoids (fGC), estrogens (fE), and progestagen (fP) metabolite concentrations in wild baboons ( Papio cynocephalus). Quadruplicate subsamples of fecal samples ( n=29) collected at Amboseli National Park and its environs were subjected to four different storage conditions prior to lyophilization, in order to determine the effects of storage on subsequent steroid concentrations, as assessed by 125 I radioimmunoassays. As expected, the best alternative to the “initial condition” of lyophilization at three days after collection was to freeze fecal samples at −20 °C for two weeks prior to lyophilization. This storage method resulted in no significant change from initial steroid concentrations for fE, fT, or fP, although fGC showed a slight but significant decline. Storage for two weeks in a charcoal refrigerator caused a mean increase in all four steroid concentrations. However, the results from this storage condition were robust in terms of practical questions asked of the data: fE and fP values still reflected pregnant versus non-pregnant states in baboon females; a fGC profile constructed by age class resembled that created from the samples from the initial condition, although slightly inflated across age classes; and there were only moderate changes in relative fT concentrations across adult males. Knowledge of the effects of storage upon each steroid analyzed within one’s study is a necessary component in determining the optimal compromise for storage protocol in a particular research project.

Behavioral Approaches to Conservation in the Wild

List of contributors Preface General acknowledgments Part I. Problems and Issues: 1. Linking conservation and behavior Janine R. Clemmons and Richard Buchholz 2. Integrating behavior into conservation biology: potentials and limitations Steven R. Beissinger 3. Why hire a behaviorist into a conservation or management team? Peter Arcese, Lukas F. Keller and John R. Cary 4. Conservation, behavior and 99% of the world's biodiversity: is our ignorance really bliss? Hugh Dingle, Scott P. Carroll and Jenella E. Loye Part II. Conservation and the Four Levels of Behavioral Study: 5. Environmental stress, field endocrinology and conservation biology John C. Wingfield, Kathleen Hunt, Creagh Breuner, Kent Dunlap, Gene S. Fowler, Leonard Freed and Jaan Lepson 6. Conservation and the ontogeny of behavior Ian G. McLean 7. Hatching asynchrony in parrots: boon or bane for sustainable use? Scott H. Stoleson and Steven R. Beissinger 8. Behavioral variation: a valuable but neglected biodiversity Richard Buchholz and Janine R. Clemmons Part III. Examples and Case Studies: 9. Bioacoustics as a tool in conservation studies Luis F. Baptista and Sandra L. L. Gaunt 10. Mating systems, effective population size and conservation of natural populations Patricia G. Parker and Thomas A. Waite 11. The importance of social behavior studies for conservation Jan Komdeur and Charlotte Deerenberg 12. Linking environmental toxicology, ethology and conservation Edmund H. Smith and Dennis T. Logan 13. The problem of photopollution for sea turtles and other nocturnal animals Blair E. Witherington 14. Light, behavior and conservation of forest-dwelling organisms John A. Endler 15. On becoming a conservation biologist: autobiography and advice Katherine Ralls Author acknowledgments Index.

Recent advances in noninvasive techniques to monitor hormone-behavior interactions.

This paper reviews recent advances in field endocrinology, a focus as well as a method in primatology and behavioral ecology that permits the examination of social behavior and life history through hormonal investigations in natural settings. Endocrine data complements the traditional behavioral data collected by field scientists by providing quantitative measures for the examination of adaptive tradeoffs, costs of social strategies, and reproductive and social significance of mating events. Further, investigations of the physiological mechanisms of reproductive constraint provide tests of the adaptive significance of reproductive skew in cooperative and competitive breeders. Hormone data also can provide insights into the costs of competition and aggression and the role of temperament in individual reproductive success and the evolution of social systems. New, noninvasive methods for the collection of this information have augmented and expanded field endocrinology through the use of techniques that do not require potentially confounding physical or physiological manipulations. Specifically, urine and fecal samples can be collected from free-ranging animals and contain gonadal and adrenal hormones that parallel profiles of serum hormones. Sampling, preservation, extraction, and assay methods for the analysis of excreted steroids are reviewed along with the species and questions to which these methods have been applied.