Special Issue "Advances in Wildlife Endocrinology and Reproduction"

A special issue of Animals (ISSN 2076-2615). This special issue belongs to the section "Wildlife".

Deadline for manuscript submissions: 31 January 2022.

Special Issue Editors

Prof. Dr. Isabel Barja Núñez
E-Mail Website
Guest Editor
Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, 28049 Madrid, Spain
Interests: animal behavior; chemical communication; ecology, etho- and eco-physiology; reproduction; vertebrates; wildlife conservation
Dr. Álvaro Navarro-Castilla
E-Mail Website
Guest Editor
Universidad Autónoma de Madrid, Ciudad Universitaria de Cantoblanco, Madrid 28049, Spain
Interests: animal behavior; ecology; etho- and eco-physiology; inter-species interactions; vertebrates; wildlife conservation

Special Issue Information

Dear Colleagues,

Wildlife populations are continuously exposed to environmental and human changes that inevitably impose different challenges. The endocrine system is particularly involved in addressing such situations because hormones play a key role in the successful adaptation to the ever-changing environment, by helping to maintain homeostasis, i.e., keeping appropriate internal conditions, while also controlling several physiological processes intimately connected with behavior, reproduction, growth, health, and survival. In this regard, the innovation in hormone analysis techniques has advanced in recent years providing valuable insights to understand how animals cope and act when facing every changing situation in nature. Today, hormone analysis is an accurate, effective, and widely accepted tool for monitoring both physiological stress responses and the reproductive function in wildlife, two major components for the conservation of species. Furthermore, hormonal analysis can be measured not only in plasma but also non-invasively, for example in faeces, which represents a more practical alternative for carrying out endocrinological studies, especially in endangered or hard to capture species. Overall, endocrine approaches may help to recognize the real impact of environmental changes and other perturbations on individuals and populations, understanding associated behavioral responses, and even anticipating the decline of a threatened population by revealing problems leading to reproductive failure. Therefore, contributions targeting, but not limited to, the following topics are welcome:

  • research on wildlife endocrine requirements;
  • potential causes altering hormones function;
  • physiological stress responses to environmental (competition, predation risk, climatic change…) and anthropogenic stressors;
  • hormone monitoring for analyzing biological mechanisms linked to some observed behaviors of animals;
  • developments of new and innovative methods for monitoring endocrine responses in wildlife;
  • advances in conservation endocrinology, i.e., studies showing application of innovative approaches to the conservation of threatened or endangered species;
  • laboratory and captive performed studies with clear implications on the management and conservation free-ranging populations;

This Special Issue aims at gathering the latest findings and technical developments in wildlife endocrinology and reproduction needed for achieving a proper understanding and its successful application for animal welfare, reproduction, and conservation strategies.

Prof. Dr. Isabel Barja Núñez
Dr. Álvaro Navarro-Castilla
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Animals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • animal physiology
  • behavior
  • ecology
  • hormone monitoring
  • reproductive biology
  • steroids
  • stressors

Published Papers

This special issue is now open for submission, see below for planned papers.

Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Title: Long-Tailed Macaque diets and reproductive function as it relates to Human-wildlife conflict and coexistence in Malaysia
Authors: Muhammed Mikail1, 2, Tengku Rinalfi Putra Tengku Azizan *1, 2, Hasliza Abu Hassim 1, 3, Azlan Che' Amat 2, 4
Affiliation: Department of Veterinary Preclinical Sciences, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul-Ehsan, Malaysia. [email protected] (M.M), [email protected] (TRPTA), [email protected] (H.A.H) 2 Wildlife Research Centre, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul-Ehsan, Malaysia. 3 Laboratory of Sustainable Animal Production and Biodiversity, Institute of Tropical Agriculture and Food Security (ITAFoS), Universiti Putra Malaysia, 43400, Serdang, Selangor Darul-Ehsan, Malaysia. 4 Department Veterinary Clinical Studies, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400 Serdang, Selangor Darul-Ehsan, Malaysia. [email protected] (A.C.A).
Abstract: Long-tailed macaques (Macaca fascicularis) are synanthropic wildlife species that play an important role in the maintenance of a healthy ecosystem. Besides, these mammals are valued for their intrinsic value to cultural and or faith systems and their potential economic contribution to local livelihoods through rainforest tourism, hunting for bushmeat, pet trading as well as in biomedical industries. In the past, the classification of Long-tailed macaque according to the International Union for Conservation of Nature (IUCN) red list is the least concern, until recently updated and listed as vulnerable species due to declining population because of human activities. Studies indicate that macaques are the most commonly used wildlife species in biomedical research and or as laboratory animals apart from rhesus monkeys and as the great seed dispersal agent in Asia, hence aid habitat regeneration. Furthermore, been synanthropic wildlife, they are frugivorous at the same time omnivorous, their food availability and provisioned diets influence their movement patterns. Under-standing the macaque's reproductive physiology and or seasonality, diets, as well as nutritional preferences, are therefore important and will offer insight into the best way of mitigating human-long-tailed macaque hostile interaction to bring about cohesive human-long tailed macaques coexistence for successful long-tailed macaques conservation. This review highlights the reproductive physiology of long-tailed macaque, reproductive seasonality across different climatic regions of various geographies, the instinct of long-tailed macaque movement or foraging pattern, nutritional preference, as well as diets across the different climatic and its relationship to reproduction. In addition, this paper explores the knowledge of human-macaque conflict mitigation methods in Peninsular Malaysia, compared with mitigation methods across the long-tailed macaque’s distribution range, illustrating similarities and differences. Keywords Long-tailed Macaques, Diets, Reproduction, Conflict, Co-existence, Peninsular Malaysia

Title: Number of primordial follicles in juvenile ringed seals (Phoca hispida) from the Gulf of Bothnia and West Greenland
Authors: Britta Schmidt1, Julia Hollenbach2, Christian Mühlfeld3, Christiane Pfarrer2, Sara Persson4, Ursula Siebert1
Affiliation: 1Institute for Terrestrial and Aquatic Wildlife Research, University of Veterinary Medicine Hannover, Foundation, Werftstr. 6, 25761 D-Büsum, Germany 2Institute of Anatomy, University of Veterinary Medicine Hannover, Foundation, Bischofsholer Damm 15, 30173 D-Hannover, Germany 3Institute of Functional and Applied Anatomy, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 D-Hannover, Germany 4Department of Environmental Research and Monitoring, Swedish Museum of Natural History, P.O. Box 50007, SE-104 05 Stockholm, Sweden
Abstract: Primordial follicles are important for the reproduction cycle and, therefore, also for the survival of the whole population of a species. Mammals have a large pool of primordial follicles and it is thought that this pool represents the total number of oocytes. The aim of the present study was to determine the total primordial follicle number of juvenile ringed seals (Phoca hispida) from the Baltic Sea and Greenland. Overall, 52 ovaries from two ringed seal populations (West Greenland (N = 6), Gulf of Bothnia (N = 46)) were examined. All ovaries were cut into 2 mm thick slices and every slice was embedded in paraffin. Out of each embedded tissue block, a 5 µm thick section was cut and stained with haematoxylin-eosin. The mean volume of the follicles and the total volume of primordial follicles per ovary were estimated by stereology and used to calculate the total estimated number of primordial follicles. The median of the total estimated number of primordial follicles is higher in Baltic individuals than in Greenland individuals (Baltic Sea = 565,657; Greenland Sea = 122,475). This makes it difficult to calculate one total range of primordial follicles in ringed seals. The different volumes (volume density of follicles, the total follicle volume, the ovary volume and the number-weighted mean volume) differ between both examined populations, whereby the Greenland individuals always had lower volumes compared to the Baltic individuals. However, this study aims to establish a suitable morphometric protocol to analyse the delicate ovaries of marine mammals, by showing its effectiveness through provided reference data of the number and mean volume of ringed seal primordial follicles. This is used to identify potential differences between populations of different local origin.

Title: Non-Invasive Determination of the Circannual Fecal Cortisol, Androstenedione and Testosterone Variations in a Herd of Seven Male Asian Elephants (Elephas maximus) and its Relation to Climatology
Authors: Paloma Jimena de Andrés1,2*, Sara Cáceres3, Belén Crespo3; Gema Silván3 and Juan Carlos Illera3
Affiliation: 1 La Reserva del Castillo de las Guardas, El Castillo de las Guardas, Sevilla, Spain. 2 Department of Medicine and Surgery, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain 3 Department of Phisiology, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain.
Abstract: The measurement of stress and reproductive hormones by non-invasive methods in wild species has a special interest. To assess whether the adrenal and gonadal hormones show a circannual varia-tions in male Asian elephants and to evaluate if there are any influences of the climatology variables with respect to the hormonal secretion, fecal samples were taken from a herd of 7 Asian elephants over a 14-month period to later determine the concentrations of fecal testosterone (T), andros-tenedione (A4), and cortisol (C) by a previously validated immunoassay technique. Data regarding to three climatic variables in the place and period of study were collected: monthly mean values of temperature, humidity and rainfall. Levels of T and A4 showed two peaks in July (T: 1088,35 ± 131,04 ng/g; A4: 480,40 ± 50,86 ng/g) and October (T: 825,09 ± 31,60 ng/g; A4: 319,96 ± 32,69 ng/g) (p < 0,05). Our results showed a clear annual pattern of fecal androgen secretion dependent on temperature (T and A4), and humidity (T). Male musth was initially detected during the first T and A4 peaks. The highest concentrations of C were observed in September (156,67 ± 60,89 ng/g) (p < 0,05); probably due to the stressful fights observed because of the period of musth. The observed results of T, A4 and C fecal levels were similar to that obtained by invasive methods. In conclusion, fecal secretion of the three hormones in captive male Asian elephants followed a circannual variation related in some cases to different weather factors.

Title: Implications of Androgens in Behaviour and Reproduction of White Rhinoceros (Ceratotherium simum)
Authors: Leticia Martínez1*, Gema Silván1, Sara Cáceres1, José Manuel Caperos2, Belen Crespo1, Jesús Martínez3, Miguel Casares4, and Juan Carlos Illera1
Affiliation: 1 Department Animal Physiology, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain. 2 University of Comillas, Social Sciences Faculty, Dept. of Psychology. Calle Universidad Comillas 3, 28049 Madrid, Spain. 3 Zoological Area of Parques Reunidos Group. Casa de Campo s/n, 28011 Madrid, Spain. 4 Bioparc of Valencia. Avenida Pio Baroja 3, 46015 Valencia, Spain.
Abstract: Conservation of white rhinoceros is still a major concern for many scientists, due to the high poaching rate and their low reproductive success in captivity. Non-invasive hormonal techniques are powerful tools to deepen into the endocrinology of different species and their reproductive bi-ology. Androgens are known to have various effects on different behaviours, especially socio-sexual behaviour. We have analysed the concentration of androgens in 572 faecal samples from 15 dif-ferent white rhinoceros kept in three different habitat conditions (captivity, semi-captivity, free-ranging). We used a competitive EIA to analyse androgen (A: 4-androsten-17β-ol-3-one) concentrations. We studied behavioural patterns and mean androgen concentration in order to stablish whether or not a seasonal reproductive pattern influences hormonal concentrations, and how is it related to socio-sexual behaviour to improve reproduction in captivity and wildlife management. A statistically significant androgen increase was found in relation to aggressive, sexual and territorial behaviour of the white rhinoceros. Significant higher androgen concentration was found during summer in free ranging rhinos, which can be related to a seasonal reproductive pattern in this species that disappeared in captivity. Our findings suggest that a seasonal repro-ductive trend occurs only in free-ranging white rhinoceros and disappears in captivity. This may be affecting their natural biological rhythms developing changes in socio-sexual behaviour and leading to reproduction failure in captivity.

Title: Effects of Social Environment and Habitat Conditions in Faecal Glucocorticoid Metabolites in White Rhinoceros (Ceratotheri-um simum)
Authors: Leticia Martínez1*, Gema Silván1, Sara Cáceres1, José Manuel Caperos2, Belen Crespo1, Jesús Martínez3, Miguel Casares4, and Juan Carlos Illera1
Affiliation: Department Animal Physiology, Veterinary Faculty, Complutense University of Madrid, Madrid, Spain
Abstract: White rhinoceroses are the most social and gregarious species from all the rhinoceroses known worldwide. In this species, habitat conditions seem to play a very important role in their repro-duction success and behaviour. One of the most critical effects of elevated glucocorticoid concen-trations, especially in threatened species, is its relation to chronic stress that could potentially lead to immunosuppression and reduced reproductive activity. Our aim is to determine how different habitat conditions might be influencing the secretion of faecal glucocorticoids in white rhinoceroses. We have analysed the concentration of faecal glucocorticoid metabolites (fGCM) in 572 faecal samples from 15 white rhinoceroses kept in three different habitat conditions (2 captive groups and 1 semi-captive/free-ranging group). All samples were analysed by competitive EIA to establish fGCM levels. We found that females showed statistically higher fGCM, possibly due to the different excretion routs among sexes or the influence of the sexual steroids on the H-H-A axis. There was no significant difference between the fGCM concentrations between seasons (summer vs winter) in none of our three groups studied. Although not all the variables known to control the secretion of glucocorticoids could be examined, our results showed a linear relationship between the three groups and their glucocorticoid concentration, suggesting that the more restrictive habitat and so-cial conditions, the higher glucocorticoid concentration. We conclude that the analysis of gluco-corticoids in relation to other factors, are powerful tools to assess adrenocortical response in white rhinoceros in order to broaden the knowledge of their reproductive biology and improve the management of the species.

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