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Hernández A, Torres R, Montoya B. Incubation as a driver of maternal effects: Temperature influences levels of yolk maternally derived 5α-dihydrotestosterone. Gen Comp Endocrinol 2024; 347:114420. [PMID: 38056529 DOI: 10.1016/j.ygcen.2023.114420] [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: 05/26/2023] [Revised: 11/15/2023] [Accepted: 11/26/2023] [Indexed: 12/08/2023]
Abstract
In birds, maternal hormones deposited into eggs in response to environmental stimuli can impact offspring phenotype. Although less studied, environmental conditions can also influence females' incubation behavior, which might play a role in regulating embryo exposure to maternal hormones through changes in incubation temperature that affect the activity of the enzymes responsible for converting testosterone (T) to 5α-dihydrotestosterone (DHT) or estradiol. Here, we tested the hypothesis that the initial T content of the yolk and incubation temperature determine exposure to T metabolites during early embryo development. In the Japanese quail (Coturnix japonica), we experimentally manipulated yolk T and incubation temperature (38° C versus 36° C) and analyzed DHT and estradiol titers on day four of incubation. We found that eggs with experimentally increased T and those incubated at 36° C showed higher DHT concentration in egg yolk (with no synergistic effect of the two treatments). Estradiol titers were not affected by T manipulation or incubation temperature. Our study suggests that incubation temperature influences DHT titers and may act as an understudied source of maternal influence on offspring phenotype.
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Affiliation(s)
- América Hernández
- Doctorado en Ciencias Biológicas, Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala 90000, Mexico; Estación Científica La Malinche, Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala 90000, Mexico; Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - Roxana Torres
- Instituto de Ecología, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico.
| | - Bibiana Montoya
- Estación Científica La Malinche, Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, Tlaxcala 90000, Mexico.
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2
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Titon SCM, Junior BT, Assis VR, Cobo de Figueiredo A, Floreste FR, Lima AS, Gomes FR. Testosterone immunomodulation in free-living and captive Rhinella icterica male toads. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220118. [PMID: 37305916 PMCID: PMC10258661 DOI: 10.1098/rstb.2022.0118] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 03/01/2023] [Indexed: 06/13/2023] Open
Abstract
Testosterone (T) regulates immune function, with both immunostimulatory and immunosuppressive effects on several vertebrates. We investigated the covariation between plasma T and corticosterone (CORT) levels and immunity (plasma bacterial killing ability (BKA), and neutrophil to lymphocyte ratio (NLR)) in free-living Rhinella icterica male toads inside and outside the reproductive season. We found an overall positive correlation between steroids and immune traits, with toads during the reproductive season displaying increased T, CORT and BKA. We also investigated the T transdermal application effects on T, CORT, phagocytosis of blood cells, BKA and NLR in captive toads. Toads were treated with T (1, 10 or 100 µg) or vehicle (sesame oil) for eight consecutive days. Animals were bled on the first and eighth days of treatment. Increased plasma T was observed on the first and last day of T-treatment, while increased BKA was observed following all T doses on the last day, with a positive correlation between T and BKA. Plasma CORT, NLR and phagocytosis increased on the last day for all T-treated and vehicle groups. Overall, we demonstrated a positive covariation between T and immune traits in the field and T-induced augmented BKA in captive toads, indicating a T immunoenhancing effect in R. icterica males. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.
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Affiliation(s)
| | - Braz Titon Junior
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
| | - Vania Regina Assis
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
| | - Aymam Cobo de Figueiredo
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
| | - Felipe Rangel Floreste
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
| | - Alan Siqueira Lima
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
| | - Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, 05508-090 São Paulo, São Paulo, Brazil
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3
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Li G, Wang Q, Zhang M, Hu B, Han S, Xiang C, Yuan G, He H. Male-Biased Parasitism of Brandt's Voles ( Lasiopodomys brandtii) in Inner Mongolia, China. Animals (Basel) 2023; 13:ani13081290. [PMID: 37106853 PMCID: PMC10135223 DOI: 10.3390/ani13081290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/03/2023] [Accepted: 04/07/2023] [Indexed: 04/29/2023] Open
Abstract
The abundance and prevalence of parasitic infection often vary in different host sexes, and this phenomenon has been named sex-biased parasitism. Brandt's voles are the dominant rodent species in typical steppe habitat and are widely distributed in Inner Mongolia, China, but the prevalence of parasites in Brandt's voles are poorly reported. In this study, we investigated the prevalence of six intestinal parasites in Brandt's voles in May, June, July, and August 2022 around the Xilingol Grassland in Inner Mongolia, China. The results showed that Syphacia obvelata, Aspiculuris tetraptera, and Trichostrongylidae family were the dominant intestinal parasites in Brandt's voles that we captured in this study, and the infection rates of the three parasites were significantly higher in males than females, which showed obvious male-biased parasitism. Season and human activities such as grazing had no significant effect on the infection rates for different parasites, while the parasite reproduction level was higher when the ambient temperature was around 18 °C. Sexual size dimorphism was ubiquitous in Brandt's voles, and it was mainly manifested by the differences in body weight and length between males and females. Simple linear regression analysis showed a significant positive correlation between bodyweight and parasite infection rates, so the sex-biased parasitism in Brandt's voles could be explained by the body size hypothesis, as a larger body could provide more ecological niches for parasitic infection.
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Affiliation(s)
- Gaojian Li
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100101, China
| | - Qinghe Wang
- Nanyang Wild Animals and Plants Protection Station, Nanyang 473000, China
| | - Min Zhang
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Bin Hu
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100101, China
| | - Shuyi Han
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100101, China
| | - Chen Xiang
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
- University of Chinese Academy of Sciences, Beijing 100101, China
| | - Guohui Yuan
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Hongxuan He
- National Research Center for Wildlife-Borne Diseases, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
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4
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Nelson-Flower MJ, Grieves LA, Reid JM, Germain RR, Lazic S, Taylor SS, MacDougall-Shackleton EA, Arcese P. Immune genotypes, immune responses, and survival in a wild bird population. Mol Ecol 2023. [PMID: 36919652 DOI: 10.1111/mec.16923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 02/18/2023] [Accepted: 03/02/2023] [Indexed: 03/16/2023]
Abstract
Individuals vary in their immune genotype, inbreeding coefficient f, immune responses, survival to adulthood, and adult longevity. However, whether immune genes predict survival or longevity, whether such relationships are mediated through immune responses, and how f affects immune genotype remain unclear. We use a wild song sparrow (Melospiza melodia) population in which survival to adulthood, adult longevity, and f were measured precisely, and in which immune responses have previously been assessed. We investigate four toll-like receptor (TLR) and the major histocompatibility complex (MHC) class IIB exon 2 genes. We test whether immune genes predict fitness (survival to adulthood or adult longevity); whether immune genes predict immune response; whether immune response predicts fitness and whether fitness, immune responses, or immune genotypes are correlated with f. We find that survival to adulthood is not associated with immune gene variation, but adult longevity is decreased by high MHC allele diversity (especially in birds that were relatively outbred), and by the presence of a specific MHC supertype. Immune responses were affected by specific immune genotypes. Survival to adulthood and adult longevity were not predicted by immune response, implying caution in the use of immune response as a predictor for fitness. We also found no relationship between f and immune genotype. This finding indicates that immune gene associations with longevity and immune response are not artefacts of f, and suggests that pathogen-mediated selection at functional loci can slow the loss of genetic variation arising from genetic drift and small population size.
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Affiliation(s)
- Martha J Nelson-Flower
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Biology, Langara College, Vancouver, British Columbia, Canada
| | - Leanne A Grieves
- Department of Biology, University of Western Ontario, London, Ontario, Canada
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Jane M Reid
- Centre for Biodiversity Dynamics, Institut for Biologi, NTNU, Trondheim, Norway
- School of Biological Sciences, University of Aberdeen, Aberdeen, UK
| | - Ryan R Germain
- Center for Macroecology, Evolution and Climate, GLOBE Institute, University of Copenhagen, Kobenhavn, Denmark
| | - Savo Lazic
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Sabrina S Taylor
- School of Renewable Natural Resources, Louisiana State University and AgCenter, Baton Rouge, Louisiana, USA
| | | | - Peter Arcese
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Sharma A, Tripathi V, Kumar V. Control and adaptability of seasonal changes in behavior and physiology of latitudinal avian migrants: Insights from laboratory studies in Palearctic-Indian migratory buntings. JOURNAL OF EXPERIMENTAL ZOOLOGY. PART A, ECOLOGICAL AND INTEGRATIVE PHYSIOLOGY 2022; 337:902-918. [PMID: 35677956 DOI: 10.1002/jez.2631] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/21/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
Twice-a-year migrations, one in autumn and the other in spring, occur within a discrete time window with striking alterations in the behavior and physiology, as regulated by the interaction of endogenous rhythms with prevailing photoperiod. These seasonal voyages are not isolated events; rather, they are part of an overall annual itinerary and remain closely coupled to the other annual subcycles, called seasonal life history states (LHSs). The success of migration depends on appropriate timing of the initiation and termination of each LHS, for example, reproduction, molt, summer nonmigratory, preautumn migratory (fattening and weight gain), autumn migratory, winter nonmigratory (wnM), prevernal (spring) migratory (fattening and weight gain), and spring migratory LHSs. Migration-linked photoperiod-induced changes include the body fattening and weight gain, nocturnal Zugunruhe (migratory restlessness), elevated triglycerides and free fatty acids, triiodothyronine and corticosterone levels. Hypothalamic expression of the thyroid hormone-responsive dio2 and dio3, light-responsive per2, cry1, and adcyap1 and th (tyrosine hydroxylase, involved in dopamine biosynthesis) genes also show significant changes with transition from wnM to the vernal migratory LHS. Concurrent changes in the expression of genes associated with lipid metabolism and its transport also occur in the liver and flight muscles, respectively. Interestingly, there are clear differences in the behavioral and physiological phenotypes, and associated molecular changes, between the autumn and vernal migrations. In this review, we discuss seasonal changes in the behavior and physiology, and present molecular insights into the development of migratory phenotypes in latitudinal avian migrants, with special reference to Palearctic-Indian migratory buntings.
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Affiliation(s)
- Aakansha Sharma
- Department of Zoology, IndoUS Center in Chronobiology, University of Delhi, Delhi, India
| | - Vatsala Tripathi
- Department of Zoology, Dyal Singh College, University of Delhi, Delhi, India
| | - Vinod Kumar
- Department of Zoology, IndoUS Center in Chronobiology, University of Delhi, Delhi, India
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6
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Impacts of synthetic androgen and estrogenic antagonist administration on growth performance, sex steroids hormones, and immune markers of male and female broilers. Poult Sci 2022; 102:102244. [PMID: 36335738 PMCID: PMC9640317 DOI: 10.1016/j.psj.2022.102244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 09/23/2022] [Accepted: 10/08/2022] [Indexed: 11/06/2022] Open
Abstract
The influence of synthetic androgen and estrogenic antagonists (Tamoxifen) on body characteristics and immune response of male and female broilers and the correlation between sex hormone levels were estimated in our experiment. One day old chicks were sexed, and chicks of each sex were randomly distributed on three experimental treatments; the first treatment group (TAM20) chicks were supplied with estrogenic antagonist tamoxifen citrate 20 mg/kg body weight through oral administration for four times every other day from third until ninth d; Androgen treatment chicks were injected intramuscular with veterinary androgen AD GAN@ (Boldenone Undecylenate 50 mg) 1 cm/10 kg body weight at fifth and ninth day, and the third treatment was control. Androgen treatment reported the highest feed intake with the lowest for TAM20 treatment. Concerning carcass characteristics, early androgen injection increased breast percentage significantly compared to TAM20 treatment. Androgen supplementation increased significantly comb the percentage. However, TAM20 decreased it particularly compared to control. Moreover, the percentage of comb and shanks was substantially higher for males than females. Concerning the effects of both treatments on sex hormones, androgen showed favorable effects on testosterone and estrogen compared to Tamoxifen 20 treatment. On the other hand, the administration of TAM 20 improves phagocytic activity compared to androgen administration.
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7
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Fuxjager MJ, Fusani L, Schlinger BA. Physiological innovation and the evolutionary elaboration of courtship behaviour. Anim Behav 2022. [DOI: 10.1016/j.anbehav.2021.03.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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8
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Gołyszny M, Obuchowicz E, Zieliński M. Neuropeptides as regulators of the hypothalamus-pituitary-gonadal (HPG) axis activity and their putative roles in stress-induced fertility disorders. Neuropeptides 2022; 91:102216. [PMID: 34974357 DOI: 10.1016/j.npep.2021.102216] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 09/21/2021] [Accepted: 10/05/2021] [Indexed: 11/24/2022]
Abstract
Neuropeptides being regulators of the hypothalamus-pituitary-adrenal (HPA) axis activity, also affect the function of the hypothalamus-pituitary-gonadal (HPG) axis by regulating gonadotrophin-releasing hormone (GnRH) secretion from hypothalamic neurons. Here, we review the available data on how neuropeptides affect HPG axis activity directly or indirectly via their influence on the HPA axis. The putative role of neuropeptides in stress-induced infertility, such as polycystic ovary syndrome, is also described. This review discusses both well-known neuropeptides (i.e., kisspeptin, Kp; oxytocin, OT; arginine-vasopressin, AVP) and more recently discovered peptides (i.e., relaxin-3, RLN-3; nesfatin-1, NEFA; phoenixin, PNX; spexin, SPX). For the first time, we present an up-to-date review of all published data regarding interactions between the aforementioned neuropeptide systems. The reviewed literature suggest new pathophysiological mechanisms leading to fertility disturbances that are induced by stress.
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Affiliation(s)
- Miłosz Gołyszny
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
| | - Ewa Obuchowicz
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
| | - Michał Zieliński
- Department of Pharmacology, Faculty of Medical Sciences in Katowice, Medical University of Silesia, Medyków 18 Street, 40-752 Katowice, Poland.
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9
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Cassettari BO, Madelaire CB, Gomes FR. Elevated corticosterone levels are associated with increased immunocompetence in male toads, both when calling and under experimental conditions. Horm Behav 2022; 137:105083. [PMID: 34773784 DOI: 10.1016/j.yhbeh.2021.105083] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 10/20/2021] [Accepted: 10/22/2021] [Indexed: 12/31/2022]
Abstract
Circulating androgens can influence immune responses and sexual traits in male vertebrates. However, in the last 20 years, glucocorticoids have also been implicated as a possible source of variation in male sexual traits and immunocompetence. In this context, we studied the relations between male vocal mating display, immunity, androgens, and glucocorticoids in the explosive breeding toad Rhinella granulosa. In the field, males with high calling effort display either high- or low-corticosterone (CORT) plasma levels, but only males with both high calling effort and high CORT plasma levels showed high bacterial killing ability (BKA), suggesting that the acute CORT elevation can be immunostimulatory. CORT treatments increased BKA in laboratory experiments, confirming the functional relationship observed in the field. However, toads treated with a low dose of CORT increased BKA for 10 h after the treatment, while toads that received a high dose increased BKA for only 1 h after the treatment. These results indicate that different CORT doses can result in temporal differences in the immune response. We did not find any relationship between calling effort, immune response (BKA and PHA swelling response), and testosterone plasma levels in the field, or any effects of testosterone treatment on immunocompetence. Our results suggest a complex relationship between calling effort and immunity, mediated by CORT plasma levels.
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Affiliation(s)
- Bruna Oliveira Cassettari
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, n° 321, 05508-900 São Paulo, SP, Brazil.
| | - Carla Bonetti Madelaire
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, n° 321, 05508-900 São Paulo, SP, Brazil
| | - Fernando Ribeiro Gomes
- Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo, Rua do Matão, trav. 14, n° 321, 05508-900 São Paulo, SP, Brazil
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10
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Goretskaia MY, Beme IR. Influence of Testosterone on Different Aspects of Bird Behavior and Physiology. BIOL BULL+ 2021. [DOI: 10.1134/s1062359021080094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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11
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Names GR, Krause JS, Schultz EM, Angelier F, Parenteau C, Ribout C, Hahn TP, Wingfield JC. Relationships between avian malaria resilience and corticosterone, testosterone and prolactin in a Hawaiian songbird. Gen Comp Endocrinol 2021; 308:113784. [PMID: 33862049 DOI: 10.1016/j.ygcen.2021.113784] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/23/2021] [Accepted: 04/09/2021] [Indexed: 01/19/2023]
Abstract
Glucocorticoids, androgens, and prolactin regulate metabolism and reproduction, but they also play critical roles in immunomodulation. Since the introduction of avian malaria to Hawaii a century ago, low elevation populations of the Hawaii Amakihi (Chlorodrepanis virens) that have experienced strong selection by avian malaria have evolved increased resilience (the ability to recover from infection), while high elevation populations that have undergone weak selection remain less resilient. We investigated how variation in malaria selection has affected corticosterone, testosterone, and prolactin hormone levels in Amakihi during the breeding season. We predicted that baseline corticosterone and testosterone (which have immunosuppressive functions) would be reduced in low elevation and malaria-infected birds, while stress-induced corticosterone and prolactin (which have immunostimulatory functions) would be greater in low elevation and malaria-infected birds. As predicted, prolactin was significantly higher in malaria-infected than uninfected females (although more robust sample sizes would help to confirm this relationship), while testosterone trended higher in malaria-infected than uninfected males and, surprisingly, neither baseline nor stress-induced CORT varied with malaria infection. Contrary to our predictions, stress-induced corticosterone was significantly lower in low than high elevation birds while testosterone in males and prolactin in females did not vary by elevation, suggesting that Amakihi hormone modulation across elevation is determined by variables other than disease selection (e.g., timing of breeding, energetic challenges). Our results shed new light on relationships between introduced disease and hormone modulation, and they raise new questions that could be explored in experimental settings.
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Affiliation(s)
- Gabrielle R Names
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA.
| | - Jesse S Krause
- Department of Biology, University of Nevada Reno, 1664 North Virginia Street, Reno, NV 89557, USA
| | - Elizabeth M Schultz
- Department of Biology, Wittenberg University, 200 W Ward Street, Springfield, OH 45504, USA
| | - Frédéric Angelier
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Charline Parenteau
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Cécile Ribout
- Centre d'Etudes Biologiques de Chizé, CNRS, La Rochelle Université, UMR 7372, 405 Route de Prissé la Charrière, Villiers-en-Bois, 79360 France
| | - Thomas P Hahn
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
| | - John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California Davis, One Shields Avenue, Davis, CA 95616, USA
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12
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Tobiansky DJ, Long KM, Hamden JE, Brawn JD, Fuxjager MJ. Cost-reducing traits for agonistic head collisions: a case for neurophysiology. Integr Comp Biol 2021; 61:1394-1405. [PMID: 33885750 DOI: 10.1093/icb/icab034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many animal species have evolved extreme behaviors requiring them to engage in repeated high-impact collisions. These behaviors include mating displays like headbutting in sheep and drumming in woodpeckers. To our knowledge, these taxa do not experience any notable acute head trauma, even though the deceleration forces would cause traumatic brain injury in most animals. Previous research has focused on skeletomuscular morphology, biomechanics, and material properties in an attempt to explain how animals moderate these high-impact forces. However, many of these behaviors are understudied, and most morphological or computational studies make assumptions about the behavior without accounting for the physiology of an organism. Studying neurophysiological and immune adaptations that co-vary with these behaviors can highlight unique or synergistic solutions to seemingly deleterious behavioral displays. Here, we argue that selection for repeated, high-impact head collisions may rely on a suite of coadaptations in intracranial physiology as a cost-reducing mechanism. We propose that there are three physiological systems that could mitigate the effects of repeated head trauma: (i) the innate neuroimmune response, (ii) the glymphatic system, and (iii) the choroid plexus. These systems are interconnected yet can evolve in an independent manner. We then briefly describe the function of these systems, their role in head trauma, and research that has examined how these systems may evolve to help reduce the cost of repeated, forceful head impacts. Ultimately, we note that little is known about cost-reducing intracranial mechanisms making it a novel field of comparative study that is ripe for exploration.
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Affiliation(s)
| | - Kira M Long
- The University of Illinois at Urbana-Champaign, Urbana-Champaign, IL USAKML
| | | | - Jeffrey D Brawn
- The University of Illinois at Urbana-Champaign, Urbana-Champaign, IL USAJDB
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13
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Argaez V, Pruett JA, Seddon RJ, Solano-Zavaleta I, Hews DK, Zúñiga-Vega JJ. Steroid hormones, ectoparasites, and color: Sex, species, and seasonal differences in Sceloporus lizards. Gen Comp Endocrinol 2021; 304:113717. [PMID: 33476662 DOI: 10.1016/j.ygcen.2021.113717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 11/06/2020] [Accepted: 01/14/2021] [Indexed: 12/20/2022]
Abstract
Testosterone, in addition to promoting the expression of sexual ornaments can negatively affect immune function, leaving individuals more susceptible to parasites (immunocompetence handicap hypothesis). Immunosuppressive effects of testosterone also can occur indirectly, through increased glucocorticoid hormones (corticosterone, cortisol). Therefore, the expression of sexual ornaments and the ability to respond to parasites and diseases may be influenced by the interaction between testosterone and corticosterone. In this study we examined correlations of both testosterone and corticosterone with ectoparasite load and with expression of colorful sexual ornaments (patches on belly and throat) in three species of Sceloporus lizards (S. grammicus, S. megalepidurus, S. torquatus). In addition, we evaluated contributions of sex, body condition, and reproductive season. We expected that individuals with higher testosterone and lower corticosterone levels would have more colorful ornaments than individuals with higher corticosterone levels. In addition, if testosterone has negative effects on immune function but only at higher corticosterone levels, individuals with higher levels of testosterone and corticosterone should have higher ectoparasite loads. Contrary to these expectations, we did not detect an interaction between testosterone and corticosterone statistically affecting either ectoparasite load or the expression of colorful ornaments. Further, we did not find a positive association of either testosterone or corticosterone on ectoparasite loads in any of the three study species. Only in S. grammicus males was a hormone statistically associated with ectoparasite load, but it was a negative association with testosterone. The relationships between both hormones and different aspects of the colorful patches (brightness and chroma) varied drastically among the three species as well as between sexes. Hence, even among congeneric species, we did not observe consistent patterns among color, steroid hormones and ectoparasites. Different associations between these variables may reflect different physiological strategies for the production of colorful signals and immune defense.
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Affiliation(s)
- Víctor Argaez
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Jake A Pruett
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA; Department of Biological Sciences, Southeastern Oklahoma State University, Durant, OK 74701, USA.
| | - Ryan J Seddon
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - Israel Solano-Zavaleta
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
| | - Diana K Hews
- Department of Biology, Indiana State University, Terre Haute, IN 47809, USA.
| | - J Jaime Zúñiga-Vega
- Departamento de Ecología y Recursos Naturales, Facultad de Ciencias, Universidad Nacional Autónoma de México, Ciudad Universitaria, 04510 Ciudad de México, Mexico.
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14
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Albert G, Arnocky S, Puts DA, Hodges-Simeon CR. Can listeners assess men's self-reported health from their voice? EVOL HUM BEHAV 2021. [DOI: 10.1016/j.evolhumbehav.2020.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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15
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LaVere AA, Hamlin HJ, Lowers RH, Parrott BB, Ezenwa VO. Associations between testosterone and immune activity in alligators depend on bacteria species and temperature. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13756] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Russell H. Lowers
- Herndon Solutions Group, LLC, NASA Environmental and Medical Contract Kennedy Space Center FL USA
| | - Benjamin B. Parrott
- Odum School of Ecology University of Georgia Athens GA USA
- Savannah River Ecology Laboratory University of Georgia Aiken SC USA
| | - Vanessa O. Ezenwa
- Odum School of Ecology University of Georgia Athens GA USA
- Department of Infectious Diseases College of Veterinary Medicine University of Georgia Athens GA USA
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16
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Kharwar RK, Singh V, Haldar C. Expression of Melatonin and Glucocorticoid
Receptor Varies along with Lung-Associated Cell-Mediated Immunity
in the Jungle Bush Quail Perdicula asiatica:
a Trade-off between Melatonin and Dexamethasone. J EVOL BIOCHEM PHYS+ 2020. [DOI: 10.1134/s0022093020040079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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17
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Sur S, Sharma A, Bhardwaj SK, Kumar V. Involvement of steroid and antioxidant pathways in spleen-mediated immunity in migratory birds. Comp Biochem Physiol A Mol Integr Physiol 2020; 250:110790. [PMID: 32800933 DOI: 10.1016/j.cbpa.2020.110790] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 08/06/2020] [Accepted: 08/06/2020] [Indexed: 12/11/2022]
Abstract
The molecular underpinnings of the spleen-mediated immune functions during the period of heightened energetic needs in the year are not known in avian migrants. We investigated this, in Palearctic-Indian migratory male redheaded buntings, which exhibited vernal (spring) premigratory / early testicular maturation states under artificial long days. This was evidenced by increased dio2 and decreased dio3 mRNA expression in the hypothalamus, elevated levels of circulating corticosterone and testosterone, and enlarged testes in long-day-photostimulated birds, as compared to unstimulated controls under short days. The concomitant decrease in both mass and volume of the spleen, and increase in the heterophil/ lymphocyte ratio suggested the parallel innate immunity effects in photostimulated buntings. Importantly, we found increased mRNA expression of genes coding for the cytokines (il15 and il34), steroid receptors (nr3c2) and oxidative stress marker enzymes (gpx1 and sod1) in the spleen, suggesting the activation of both immune and antioxidant molecular pathways during the early photostimulated state. However, the splenic expressions of il1β, il6, tgfβ, ar and nos2 genes were not significantly different between long-day stimulated and short-day unstimulated birds. The negative correlation of plasma corticosterone levels with spleen mass further indicated a role of corticosterone in the modulation of the spleen function, probably via nr3c2 gene encoded mineralocorticoid receptors. These results suggest the activation of the spleen-mediated innate immunity in anticipation of the heightened energetic stress state of the photostimulated spring migratory/breeding period in migratory songbirds.
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Affiliation(s)
- Sayantan Sur
- Department of Zoology, University of Delhi, Delhi 110 007, India
| | - Aakansha Sharma
- Department of Zoology, University of Delhi, Delhi 110 007, India
| | | | - Vinod Kumar
- Department of Zoology, University of Delhi, Delhi 110 007, India.
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18
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Simkins JW, Joseph AE, Bonier F, Benowitz-Fredericks ZM. Prenatal aromatase inhibition alters postnatal immunity in domestic chickens (Gallus gallus). Gen Comp Endocrinol 2020; 294:113497. [PMID: 32360542 DOI: 10.1016/j.ygcen.2020.113497] [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: 08/23/2019] [Revised: 04/19/2020] [Accepted: 04/27/2020] [Indexed: 10/24/2022]
Abstract
In birds, exposure to exogenous testosterone during embryonic development can suppress measures of immune function; however, it is unclear whether these effects are due to direct or indirect action via aromatization. Estradiol (E2) is synthesized from testosterone by the enzyme aromatase, and this conversion is a necessary step in many signaling pathways that are ostensibly testosterone-dependent. Many lines of evidence in mammals indicate that E2 can affect immune function. We tested the hypothesis that some of the immunomodulatory effects observed in response to in ovo testosterone exposure in birds are mediated by conversion to E2 by aromatase, by using fadrozole to inhibit aromatization of endogenous testosterone during a crucial period of embryonic immune system development in domestic chickens (Gallus gallus). We then measured total IgY antibody count, response to PHA challenge, mass of thymus and bursa of Fabricius, and plasma testosterone post-hatch on days 3 and 18. Because testosterone has a reputation for immunosuppression, we predicted that if modulation of an immune measure by testosterone is dependent on aromatization, then inhibition of estrogen production by fadrozole treatment would lead to elevated measures of that parameter. Conversely, if testosterone inhibits an immune measure directly, then fadrozole treatment would likely not alter that parameter. Fadrozole treatment reduced circulating E2 in female embryos, but had no effect on males or on testosterone in either sex. Fadrozole-treated chicks had decreased day 3 plasma IgY antibody titers and a strong trend towards increased day 18 thymic mass. Furthermore, fadrozole treatment generated a positive relationship between testosterone and thymic mass in males, and tended to increase day 18 IgY levels for a given bursal mass in females. There was no effect on PHA response, bursal mass, or plasma testosterone at either age post-hatch. The alteration of several indicators of immune function in fadrozole-treated chicks implicates aromatization as a relevant pathway through which developmental exposure to testosterone can affect immunity in birds.
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Affiliation(s)
- J W Simkins
- Bucknell University, Department of Biology, 1 Dent Drive, Lewisburg, PA, USA.
| | - A E Joseph
- Bucknell University, Department of Biology, 1 Dent Drive, Lewisburg, PA, USA.
| | - F Bonier
- Queen's University, Department of Biology, 116 Barrie Street, Kingston, ON K7L 3N6, Canada.
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19
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Affiliation(s)
- Donna L Maney
- Department of Psychology, Emory University, Atlanta, GA, USA.
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20
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Wingfield JC, Goymann W, Jalabert C, Soma KK. Reprint of "Concepts derived from the Challenge Hypothesis". Horm Behav 2020; 123:104802. [PMID: 32540136 DOI: 10.1016/j.yhbeh.2020.104802] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 12/19/2022]
Abstract
The Challenge Hypothesis was developed to explain why and how regulatory mechanisms underlying patterns of testosterone secretion vary so much across species and populations as well as among and within individuals. The hypothesis has been tested many times over the past 30years in all vertebrate groups as well as some invertebrates. Some experimental tests supported the hypothesis but many did not. However, the emerging concepts and methods extend and widen the Challenge Hypothesis to potentially all endocrine systems, and not only control of secretion, but also transport mechanisms and how target cells are able to adjust their responsiveness to circulating levels of hormones independently of other tissues. The latter concept may be particularly important in explaining how tissues respond differently to the same hormone concentration. Responsiveness of the hypothalamo-pituitary-gonad (HPG) axis to environmental and social cues regulating reproductive functions may all be driven by gonadotropin-releasing hormone (GnRH) or gonadotropin-inhibiting hormone (GnIH), but the question remains as to how different contexts and social interactions result in stimulation of GnRH or GnIH release. These concepts, although suspected for many decades, continue to be explored as integral components of environmental endocrinology and underlie fundamental mechanisms by which animals, including ourselves, cope with a changing environment. Emerging mass spectrometry techniques will have a tremendous impact enabling measurement of multiple steroids in specific brain regions. Such data will provide greater spatial resolution for studying how social challenges impact multiple steroids within the brain. Potentially the Challenge Hypothesis will continue to stimulate new ways to explore hormone-behavior interactions and generate future hypotheses.
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Affiliation(s)
- John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Wolfgang Goymann
- Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Cecilia Jalabert
- Department of Zoology, University of British Columbia, Vancouver, Canada; Djavad Mofawaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kiran K Soma
- Department of Zoology, University of British Columbia, Vancouver, Canada; Djavad Mofawaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada
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21
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Videvall E, Palinauskas V, Valkiūnas G, Hellgren O. Host Transcriptional Responses to High- and Low-Virulent Avian Malaria Parasites. Am Nat 2020; 195:1070-1084. [DOI: 10.1086/708530] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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22
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Metcalf CJE, Roth O, Graham AL. Why leveraging sex differences in immune trade-offs may illuminate the evolution of senescence. Funct Ecol 2020; 34:129-140. [PMID: 32063662 PMCID: PMC7006808 DOI: 10.1111/1365-2435.13458] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 09/10/2019] [Indexed: 12/15/2022]
Abstract
The immune system affects senescence (declines in probabilities of survival or reproduction with age), by shaping late age vulnerability to chronic inflammatory diseases and infections. It is also a dynamic interactive system that must balance competing demands across the life course. Thus, immune system function remains an important frontier in understanding the evolution of senescence.Here, we review our expanding mechanistic understanding of immune function over the life course, in the context of theoretical predictions from life-history evolution. We are especially interested in stage- and sex-dependent costs and benefits of investment in the immune system, given differential life-history priorities of the life stages and sexes.We introduce the costs likely to govern immune allocation across the life course. We then discuss theoretical expectations for differences between the sexes and their likely consequences in terms of how the immune system is both modulated by and may modulate senescence, building on information from life-history theory, experimental immunology and demography.We argue that sex differences in immune function provide a potentially powerful probe of selection pressures on the immune system across the life course. In particular, differences in 'competing' and 'caring' between the sexes have evolved across the tree of life, providing repeated instances of divergent selection pressures on immune function occurring within the same overall bauplan.We conclude by detailing an agenda for future research, including development of theoretical predictions of the differences between the sexes under an array of existing models for sex differences in immunity, and empirical tests of such predictions across the tree of life. A free http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13458/suppinfo can be found within the Supporting Information of this article.
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Affiliation(s)
| | - Olivia Roth
- GEOMAR, Marine Evolutionary EcologyHelmholtz Centre for Ocean ResearchKielGermany
| | - Andrea L. Graham
- Department of Ecology and Evolutionary BiologyPrinceton UniversityPrincetonNJUSA
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23
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Lelono A, Robledo-Ruiz DA, Berghof TVL, Parmentier HK, Riedstra B, Groothuis TG. Does paternal immunocompetence affect offspring vulnerability to maternal androgens? A study in domestic chickens. Biol Open 2019; 8:bio.045096. [PMID: 31748241 PMCID: PMC6899007 DOI: 10.1242/bio.045096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Exposure of yolk androgens can positively stimulate chick growth and competitive ability, but may negatively affect immunity. It has been hypothesized that only chicks from immunologically superior fathers can bear the cost of prenatal exposure to high androgen levels. To test this hypothesis, we paired roosters from two selection lines, one up- and one down-selected for natural antibodies (NAbs), with hens from a control line. We measured yolk testosterone and androstenedione levels, and we injected the treatment group of eggs of each female with testosterone suspended in sesame oil and the control group with sesame oil only. We then measured hatching success and growth, and characterized the humoral and cellular immune responses using three different challenges: a phyto-hemagglutinin, a lipopolysaccharide and a sheep red blood cell challenge. We found that the hatching success, body mass, initial levels of natural antibodies and the chicks’ immunological responses to the three different challenges and development were affected neither by paternal immunocompetence nor by treatment. These results do not support the hypothesis that chicks from low-NAb line fathers are more sensitive to testosterone exposure during embryonic development than chicks from high-NAb line fathers. Summary: Our study shows that there were no effects of paternal natural antibody line, increased embryonic testosterone exposure or the interaction of both on immunocompetence of chicks.
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Affiliation(s)
- Asmoro Lelono
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands .,Department of Biology, Faculty of Mathematics and Natural Sciences, University of Jember, 68121 Jember, East Java, The Republic of Indonesia
| | - Diana A Robledo-Ruiz
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Tom V L Berghof
- Department of Animal Sciences, Wageningen University & Research Animal Breeding and Genomics, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Henk K Parmentier
- Department of Animal Sciences, Wageningen University & Research Adaptation Physiology, P.O. Box 338, 6700 AH Wageningen, The Netherlands
| | - Bernd Riedstra
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
| | - Ton G Groothuis
- Behavioural Biology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747 AG, Groningen, The Netherlands
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24
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Schuppe ER, Fuxjager MJ. Phenotypic variation reveals sites of evolutionary constraint in the androgenic signaling pathway. Horm Behav 2019; 115:104538. [PMID: 31211944 DOI: 10.1016/j.yhbeh.2019.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/19/2019] [Accepted: 06/10/2019] [Indexed: 01/05/2023]
Abstract
Steroid hormone systems play an important role in shaping the evolution of vertebrate sexual traits, but several aspects of this relationship remain unclear. For example, we currently know little about how steroid signaling complexes are adapted to accommodate the emergence of behavior in response to sexual selection. We use downy woodpeckers (Dryobates pubescens) to evaluate how the machinery underlying androgen action can evolve to accommodate this bird's main territorial signal, the drum. We focus specifically on modifications to androgenic mechanisms in the primary neck muscle that actuates the hammering movements underlying this signal. Of the signaling components we examine, we find that levels of circulating testosterone (T) and androgen receptor (AR) expression are consistently increased in a way that likely enhances androgenic regulation of drumming. By contrast, the expression of nuclear receptor co-factors-the 'molecular rheostats' of steroid action-show no such relationship in our analyses. If anything, co-factors are expressed in directions that would presumably hinder androgenic regulation of the drum. These findings therefore collectively point to T levels and AR as the more evolutionarily labile components of the androgenic system, in that they are likely more apt to change over time to support sexual selection for territorial signaling in woodpeckers. Yet the signaling elements that fine-tune AR's functional effects on the genome-namely the receptor's transcriptional co-factors-do not change in such a manner, and thus may be under tighter evolutionary constraint.
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Affiliation(s)
- Eric R Schuppe
- Department of Biology, Wake Forest University, 455 Vine Street, Winston-Salem, NC 27101, United States of America
| | - Matthew J Fuxjager
- Department of Ecology and Evolutionary Biology, Brown University, Providence, RI 02912, United States of America.
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25
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Wingfield JC, Goymann W, Jalabert C, Soma KK. Concepts derived from the Challenge Hypothesis. Horm Behav 2019; 115:104550. [PMID: 31265826 DOI: 10.1016/j.yhbeh.2019.06.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 06/28/2019] [Accepted: 06/28/2019] [Indexed: 12/25/2022]
Abstract
The Challenge Hypothesis was developed to explain why and how regulatory mechanisms underlying patterns of testosterone secretion vary so much across species and populations as well as among and within individuals. The hypothesis has been tested many times over the past 30years in all vertebrate groups as well as some invertebrates. Some experimental tests supported the hypothesis but many did not. However, the emerging concepts and methods extend and widen the Challenge Hypothesis to potentially all endocrine systems, and not only control of secretion, but also transport mechanisms and how target cells are able to adjust their responsiveness to circulating levels of hormones independently of other tissues. The latter concept may be particularly important in explaining how tissues respond differently to the same hormone concentration. Responsiveness of the hypothalamo-pituitary-gonad (HPG) axis to environmental and social cues regulating reproductive functions may all be driven by gonadotropin-releasing hormone (GnRH) or gonadotropin-inhibiting hormone (GnIH), but the question remains as to how different contexts and social interactions result in stimulation of GnRH or GnIH release. These concepts, although suspected for many decades, continue to be explored as integral components of environmental endocrinology and underlie fundamental mechanisms by which animals, including ourselves, cope with a changing environment. Emerging mass spectrometry techniques will have a tremendous impact enabling measurement of multiple steroids in specific brain regions. Such data will provide greater spatial resolution for studying how social challenges impact multiple steroids within the brain. Potentially the Challenge Hypothesis will continue to stimulate new ways to explore hormone-behavior interactions and generate future hypotheses.
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Affiliation(s)
- John C Wingfield
- Department of Neurobiology, Physiology and Behavior, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Wolfgang Goymann
- Department of Behavioral Neurobiology, Max Planck Institute for Ornithology, Seewiesen, Germany
| | - Cecilia Jalabert
- Department of Zoology, University of British Columbia, Vancouver, Canada; Djavad Mofawaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | - Kiran K Soma
- Department of Zoology, University of British Columbia, Vancouver, Canada; Djavad Mofawaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada; Department of Psychology, University of British Columbia, Vancouver, Canada
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26
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Cozzarolo CS, Sironi N, Glaizot O, Pigeault R, Christe P. Sex-biased parasitism in vector-borne disease: Vector preference? PLoS One 2019; 14:e0216360. [PMID: 31048933 PMCID: PMC6497283 DOI: 10.1371/journal.pone.0216360] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 04/18/2019] [Indexed: 01/03/2023] Open
Abstract
Sex-biased infections are a recurrent observation in vertebrates. In many species, males are more parasitized than females. Two potentially complementary mechanisms are often suggested to explain this pattern: sexual differences in susceptibility mainly caused by the effect of sex hormones on immunity and differential exposure to parasites. Exposure is mostly a consequence of host behavioural traits, but vector-borne parasitic infections involve another degree of complexity due to the active role of vectors in transmission. Blood-sucking insects may make choices based on cues produced by hosts. Regarding malaria, several studies highlighted a male-biased infection by Plasmodium sp in great tits (Parus major). We hypothesize that the mosquito vector, Culex pipiens, might at least partially cause this bias by being more attracted to male birds. Intrinsic variation associated to bird sex would explain a preference of mosquitoes for males. To test this hypothesis, we provide uninfected mosquitoes with a choice between uninfected male and female nestlings. Mosquito choice is assessed by sex typing of the ingested blood. We did not observe any preference for a given sex. This result does not support our prediction of a preference of mosquitoes for male great tits during the nestling period. In conclusion, mosquitoes do not seem to have an intrinsic preference for male nestlings. However, sexually divergent traits (e.g. behaviour, odour, metabolic rate) present in adults may play a role in the attraction of mosquitoes and should be investigated.
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Affiliation(s)
| | - Nicolas Sironi
- Département d’Ecologie & Evolution, Université de Lausanne, Lausanne, Suisse
| | - Olivier Glaizot
- Département d’Ecologie & Evolution, Université de Lausanne, Lausanne, Suisse
- Musée cantonal de zoologie, Lausanne, Suisse
| | - Romain Pigeault
- Département d’Ecologie & Evolution, Université de Lausanne, Lausanne, Suisse
| | - Philippe Christe
- Département d’Ecologie & Evolution, Université de Lausanne, Lausanne, Suisse
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27
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Madelaire CB, Cassettari BDO, Gomes FR. Immunomodulation by testosterone and corticosterone in toads: Experimental evidences from transdermal application. Gen Comp Endocrinol 2019; 273:227-235. [PMID: 30195026 DOI: 10.1016/j.ygcen.2018.09.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 08/31/2018] [Accepted: 09/04/2018] [Indexed: 10/28/2022]
Abstract
Androgens and glucocorticoids play important roles in vertebrate's reproduction and display complex immunomodulatory functions that may affect survival. In anurans, testosterone and corticosterone are correlated to sexual behavior, reproduction, and immune function. Male toads (Rhinella jimi) were treated with acute doses of testosterone (T) and corticosterone (CORT) and immune variables (plasma bacterial killing ability [BKA], swelling after phytohemagglutinin [PHA] injection and the time point of maximum PHA swelling response) were measured. Transdermal T and CORT application increased androgen (T-DHT) and CORT plasma levels after 1 h of treatment, respectively, without a dose-specific effect. Transdermal T treatment did not affect BKA or PHA swelling response. Individuals treated with transdermal CORT showed an earlier maximum PHA swelling response and a tendency of lower BKA 15 h after treatment. Our results indicated that an acute experimental increase of CORT plasma levels diminished time for inflammatory resolution and suppressed non-cellular innate response.
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Affiliation(s)
- Carla Bonetti Madelaire
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil.
| | - Bruna de Oliveira Cassettari
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil
| | - Fernando Ribeiro Gomes
- USP - Universidade de São Paulo, Instituto de Biociências, Departamento de Fisiologia, Rua do Matão, trav 14 n 321, Cidade Universitária, São Paulo, SP 05508-090, Brazil
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28
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O'Brien KA, Waterman JM, Anderson WG, Bennett NC. Trade-offs between immunity and testosterone in male African ground squirrels. ACTA ACUST UNITED AC 2018; 221:jeb.177683. [PMID: 29941613 DOI: 10.1242/jeb.177683] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 06/20/2018] [Indexed: 10/28/2022]
Abstract
The immunocompetence handicap hypothesis (ICHH) proposes that testosterone has both beneficial effects on male reproductive potential and negative effects by suppressing the immune system. However, support for the ICHH has been variable and an alternative hypothesis suggests that testosterone may be acting indirectly via cortisol to suppress immunity (the stress-linked ICHH). A third hypothesis is that increased energetic investment in immunity results in the suppression of testosterone. We tested these hypotheses in male Cape ground squirrels (Xerus inauris) through two separate manipulations: first, by triggering a strong immune response using a lipopolysaccharide (LPS) injection and, secondly, by increasing circulating testosterone using silastic testosterone implants. Responding to an immune challenge significantly reduced testosterone, supporting the immune suppression hypothesis, while increasing circulating testosterone had no effect on immunocompetence, body mass, ectoparasite abundances or cortisol levels, failing to support either the ICHH or stress-linked ICHH. Our results add to the increasing body of literature that challenges the ICHH, and we conclude that the trade-off between testosterone and immunity is mediated through immune activation and not through testosterone in male Cape ground squirrels. Being able to test the ICHH, stress-linked ICHH and immune suppression hypotheses in a free-ranging mammal gives us a unique opportunity to examine the mechanisms mediating this trade-off.
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Affiliation(s)
- Kelsey A O'Brien
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Jane M Waterman
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada .,Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
| | - W Gary Anderson
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Nigel C Bennett
- Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa
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29
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Smyth KN, Caruso NM, Davies CS, Clutton-Brock TH, Drea CM. Social and endocrine correlates of immune function in meerkats: implications for the immunocompetence handicap hypothesis. ROYAL SOCIETY OPEN SCIENCE 2018; 5:180435. [PMID: 30225031 PMCID: PMC6124081 DOI: 10.1098/rsos.180435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 06/25/2018] [Indexed: 06/08/2023]
Abstract
Social status can mediate effects on the immune system, with profound consequences for individual health; nevertheless, most investigators of status-related disparities in free-ranging animals have used faecal parasite burdens to proxy immune function in the males of male-dominant species. We instead use direct measures of innate immune function (complement and natural antibodies) to examine status-related immunocompetence in both sexes of a female-dominant species. The meerkat is a unique model for such a study because it is a cooperatively breeding species in which status-related differences are extreme, evident in reproductive skew, morphology, behaviour, communication and physiology, including that dominant females naturally express the greatest total androgen (androstenedione plus testosterone) concentrations. We found that, relative to subordinates, dominant animals had reduced serum bacteria-killing abilities; also, relative to subordinate females, dominant females had reduced haemolytic complement activities. Irrespective of an individual's sex or social status, androstenedione concentrations (but not body condition, age or reproductive activity) negatively predicted concurrent immunocompetence. Thus, dominant meerkats of both sexes are immunocompromised. Moreover, in female meerkats, androstenedione perhaps acting directly or via local conversion, may exert a double-edged effect of promoting dominance and reproductive success at the cost of increased parasitism and reduced immune function. Given the prominent signalling of dominance in female meerkats, these findings may relate to the immunocompetence handicap hypothesis (ICHH); however, our data would suggest that the endocrine mechanism underlying the ICHH need not be mediated solely by testosterone and might explain trade-offs in females, as well as in males.
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Affiliation(s)
- Kendra N. Smyth
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Nicholas M. Caruso
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | - Charli S. Davies
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
| | - Tim H. Clutton-Brock
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
- Department of Zoology, University of Cambridge, Cambridge, UK
- Mammal Research Institute, University of Pretoria, Pretoria, South Africa
| | - Christine M. Drea
- University Program in Ecology, Duke University, Durham, NC, USA
- Department of Evolutionary Anthropology, Duke University, Durham, NC, USA
- Department of Biology, Duke University, Durham, NC, USA
- Kalahari Research Trust, Kuruman River Reserve, Van Zylsrus, Northern Cape, South Africa
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Loggie JW, Garner SR, Partridge CG, Dixon B, Knapp R, Neff BD. A test of the effects of androgens on immunity: No relationship between 11-ketotestosterone and immune performance in bluegill (Lepomis macrochirus). Gen Comp Endocrinol 2018; 261:1-8. [PMID: 29355535 DOI: 10.1016/j.ygcen.2018.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 01/13/2018] [Accepted: 01/13/2018] [Indexed: 11/24/2022]
Abstract
The immunosuppressive effects of androgens are a key component of the immunocompetence handicap hypothesis (ICHH). Here, we use bluegill sunfish (Lepomis macrochirus) to test two predictions arising from this hypothesis: (1) natural circulating concentrations of the androgen 11-ketotestosterone (11-KT) will be negatively related with measures of immunity, and (2) immune stimulation will lower circulating 11-KT concentration. We found no evidence for a relationship between natural circulating 11-KT concentration and measures of immunity (lymphocyte and granulocyte counts, respiratory burst, cytokine mRNA levels), and an immune stimulation with Vibrio vaccine did not affect circulating 11-KT concentration. We also performed a meta-analysis of immune stimulation studies to help interpret our results, and report evidence suggesting that immune stimulation has weaker effects on androgen levels in fishes compared to other vertebrates. These results suggest that the ICHH may not apply to all vertebrates, although it remains premature to state what factors account for the weaker evidence in fishes that androgens are immunosuppressive.
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Affiliation(s)
- John W Loggie
- Department of Biology, The University of Western Ontario, 1151 Richmond St., London, ON N6A 5B7, Canada
| | - Shawn R Garner
- Department of Biology, The University of Western Ontario, 1151 Richmond St., London, ON N6A 5B7, Canada
| | - Charlyn G Partridge
- Annis Water Resources Institute, Grand Valley State University, 740 W. Shoreline Dr., Muskegon, MI 49441, USA
| | - Brian Dixon
- Department of Biology, University of Waterloo, 200 University Ave. W., Waterloo, ON N2L 3G1, Canada
| | - Rosemary Knapp
- Department of Biology, University of Oklahoma, 730 Van Vleet Oval, Norman, OK 73019, USA
| | - Bryan D Neff
- Department of Biology, The University of Western Ontario, 1151 Richmond St., London, ON N6A 5B7, Canada.
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Nowak J, Pawłowski B, Borkowska B, Augustyniak D, Drulis-Kawa Z. No evidence for the immunocompetence handicap hypothesis in male humans. Sci Rep 2018; 8:7392. [PMID: 29743556 PMCID: PMC5943526 DOI: 10.1038/s41598-018-25694-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 04/26/2018] [Indexed: 12/11/2022] Open
Abstract
The observations that testosterone might be immunosuppressive, form the basis for the immunocompetence handicap hypothesis (ICHH). According to ICHH only high-quality individuals can maintain high levels of testosterone and afford the physiological cost of hormone-derived immunosuppression. The animal and human studies that attempted to support the ICHH by precisely defined impairment of immunity associated with high testosterone levels are inconclusive. Furthermore, human studies have used only selected immune functions and varying testosterone fractions. This is the first study examining the relationship between multiple innate and adaptive immunity and serum levels of free testosterone, total testosterone, DHT and DHEA in ninety-seven healthy men. Free testosterone and marginally DHT levels were positively correlated with the strength of the influenza post-vaccination response. Total testosterone and DHEA showed no immunomodulatory properties. Our findings did not support ICHH assumptions about immunosuppressive function of androgens. In the affluent society studied here, men with higher levels of free testosterone could afford to invest more in adaptive immunity. Since the hormone-immune relationship is complex and may depend on multiple factors, including access to food resources, androgens should be treated as immunomodulators rather than implicit immunosuppressants.
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Affiliation(s)
- Judyta Nowak
- Department of Human Biology, University of Wroclaw, Kuźnicza 35, 50-138, Wrocław, Poland.
| | - Bogusław Pawłowski
- Department of Human Biology, University of Wroclaw, Kuźnicza 35, 50-138, Wrocław, Poland
| | - Barbara Borkowska
- Department of Human Biology, University of Wroclaw, Kuźnicza 35, 50-138, Wrocław, Poland
| | - Daria Augustyniak
- Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148, Wrocław, Poland
| | - Zuzanna Drulis-Kawa
- Institute of Genetics and Microbiology, University of Wroclaw, Przybyszewskiego 63/77, 51-148, Wrocław, Poland
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Béziers P, Ducrest AL, Simon C, Roulin A. Circulating testosterone and feather-gene expression of receptors and metabolic enzymes in relation to melanin-based colouration in the barn owl. Gen Comp Endocrinol 2017; 250:36-45. [PMID: 28457648 DOI: 10.1016/j.ygcen.2017.04.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Revised: 03/11/2017] [Accepted: 04/26/2017] [Indexed: 10/19/2022]
Abstract
Knowledge of how and why secondary sexual characters are associated with sex hormones is important to understand their signalling function. Such a link can occur if i) testosterone participates in the elaboration of sex-traits, ii) the display of an ornament triggers behavioural response in conspecifics that induce a rise in testosterone, or iii) genes implicated in the elaboration of a sex-trait pleiotropically regulate testosterone physiology. To evaluate the origin of the co-variation between melanism and testosterone, we measured this hormone and the expression of enzymes involved in its metabolism in feathers of barn owl (Tyto alba) nestlings at the time of melanogenesis and in adults outside the period of melanogenesis. Male nestlings displaying smaller black feather spots had higher levels of circulating testosterone, potentially suggesting that testosterone could block the production of eumelanin pigments, or that genes involved in the production of small spots pleiotropically regulate testosterone production. In contrast, the enzyme 5α-reductase, that metabolizes testosterone to DHT, was more expressed in feathers of reddish-brown than light-reddish nestlings. This is consistent with the hypothesis that testosterone might be involved in the expression of reddish-brown pheomelanic pigments. In breeding adults, male barn owls displaying smaller black spots had higher levels of circulating testosterone, whereas in females the opposite result was detected during the rearing period, but not during incubation. The observed sex- and age-specific co-variations between black spottiness and testosterone in nestling and adult barn owls may not result from testosterone-dependent melanogenesis, but from melanogenic genes pleiotropically regulating testosterone, or from colour-specific life history strategies that influence testosterone levels.
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Affiliation(s)
- Paul Béziers
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
| | - Anne-Lyse Ducrest
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Céline Simon
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Alexandre Roulin
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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Within- and between-individual (co)variance partitioning reveals limited pleiotropic effects of testosterone on immune function, sexual signaling, and parental investment. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-017-2308-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Neuman-Lee LA, French SS. Endocrine-reproductive-immune interactions in female and male Galápagos marine iguanas. Horm Behav 2017; 88:60-69. [PMID: 27818221 DOI: 10.1016/j.yhbeh.2016.10.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 10/25/2016] [Accepted: 10/28/2016] [Indexed: 12/14/2022]
Abstract
Endocrine-immune interactions are variable across species and contexts making it difficult to discern consistent patterns. There is a paucity of data in non-model systems making these relationships even more nebulous, particularly in reptiles. In the present study, we have completed a more comprehensive test of the relationship among steroid hormones and ecologically relevant immune measures. We tested the relationship between baseline and stress-induced levels of sex and adrenal steroid hormones and standard ecoimmunological metrics in both female and male Galápagos marine iguanas (Amblyrhynchus cristatus). We found significant associations between adrenal activity and immunity, whereby females that mounted greater corticosterone responses to stress had lower basal and stress-induced immunity (i.e., bactericidal ability). Males showed the opposite relationship, suggesting sex-specific immunomodulatory actions of corticosterone. In both sexes, we observed a stress-induced increase in corticosterone, and in females a stress-induced increase in bactericidal ability. Consistent with other taxa, we also found that baseline corticosterone and testosterone in males was inversely related to baseline bactericidal ability. However, in females, we found a positive relationship between both testosterone and progesterone and bactericidal ability. Multivariate analysis did not discern any further endocrine-immune relationships, suggesting that interactions between adrenal, sex steroid hormones, and the immune system may not be direct and instead may be responding to other common stimuli, (i.e., reproductive status, energy). Taken together, these data illustrate significant endocrine-immune interactions that are highly dependent on sex and the stress state of the animal.
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Affiliation(s)
- Lorin A Neuman-Lee
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA; The Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, USA
| | - Susannah S French
- Department of Biology, Utah State University, 5305 Old Main Hill, Logan, UT 84322-5305, USA; The Ecology Center, Utah State University, 5205 Old Main Hill, Logan, UT 84322-5205, USA.
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Abstract
Through behavior, animals interact with a world where parasites abound. It is easy to understand how behavioral traits can thus have a differential effect on pathogen exposure. Harder to understand is why we observe behavioral traits to be linked to immune defense traits. Is variation in immune traits a consequence of behavior-induced variation in immunological experiences? Or is variation in behavioral traits a function of immune capabilities? Is our immune system a much bigger driver of personality than anticipated? In this review, I provide examples of how behavioral and immune traits co-vary. I then explore the different routes linking behavioral and immune traits, emphasizing on the physiological/hormonal mechanisms that could lead to immune control of behavior. Finally, I discuss why we should aim at understanding more about the mechanisms connecting these phenotypic traits.
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Affiliation(s)
- Patricia C Lopes
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
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Muriel J, Pérez-Rodríguez L, Ortiz-Santaliestra ME, Puerta M, Gil D. Sex-Specific Effects of High Yolk Androgen Levels on Constitutive and Cell-Mediated Immune Responses in Nestlings of an Altricial Passerine. Physiol Biochem Zool 2017; 90:106-117. [DOI: 10.1086/688445] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Abstract
Multidirectional interactions among the immune, endocrine, and nervous systems have been demonstrated in humans and non-human animal models for many decades by the biomedical community, but ecological and evolutionary perspectives are lacking. Neuroendocrine-immune interactions can be conceptualized using a series of feedback loops, which culminate into distinct neuroendocrine-immune phenotypes. Behavior can exert profound influences on these phenotypes, which can in turn reciprocally modulate behavior. For example, the behavioral aspects of reproduction, including courtship, aggression, mate selection and parental behaviors can impinge upon neuroendocrine-immune interactions. One classic example is the immunocompetence handicap hypothesis (ICHH), which proposes that steroid hormones act as mediators of traits important for female choice while suppressing the immune system. Reciprocally, neuroendocrine-immune pathways can promote the development of altered behavioral states, such as sickness behavior. Understanding the energetic signals that mediate neuroendocrine-immune crosstalk is an active area of research. Although the field of psychoneuroimmunology (PNI) has begun to explore this crosstalk from a biomedical standpoint, the neuroendocrine-immune-behavior nexus has been relatively underappreciated in comparative species. The field of ecoimmunology, while traditionally emphasizing the study of non-model systems from an ecological evolutionary perspective, often under natural conditions, has focused less on the physiological mechanisms underlying behavioral responses. This review summarizes neuroendocrine-immune interactions using a comparative framework to understand the ecological and evolutionary forces that shape these complex physiological interactions.
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Affiliation(s)
- Noah T Ashley
- Department of Biology, Western Kentucky University, Bowling Green, KY 42101, USA.
| | - Gregory E Demas
- Department of Biology, Center for the Integrative Study of Animal Behavior - Program in Neuroscience, Indiana University, Bloomington, IN 47405, USA
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Sin YW, Newman C, Dugdale HL, Buesching C, Mannarelli ME, Annavi G, Burke T, Macdonald DW. No Compensatory Relationship between the Innate and Adaptive Immune System in Wild-Living European Badgers. PLoS One 2016; 11:e0163773. [PMID: 27695089 PMCID: PMC5047587 DOI: 10.1371/journal.pone.0163773] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Accepted: 09/14/2016] [Indexed: 11/19/2022] Open
Abstract
The innate immune system provides the primary vertebrate defence system against pathogen invasion, but it is energetically costly and can have immune pathological effects. A previous study in sticklebacks found that intermediate major histocompatibility complex (MHC) diversity correlated with a lower leukocyte coping capacity (LCC), compared to individuals with fewer, or many, MHC alleles. The organization of the MHC genes in mammals, however, differs to the highly duplicated MHC genes in sticklebacks by having far fewer loci. Using European badgers (Meles meles), we therefore investigated whether innate immune activity, estimated functionally as the ability of an individual’s leukocytes to produce a respiratory burst, was influenced by MHC diversity. We also investigated whether LCC was influenced by factors such as age-class, sex, body condition, season, year, neutrophil and lymphocyte counts, and intensity of infection with five different pathogens. We found that LCC was not associated with specific MHC haplotypes, MHC alleles, or MHC diversity, indicating that the innate immune system did not compensate for the adaptive immune system even when there were susceptible MHC alleles/haplotypes, or when the MHC diversity was low. We also identified a seasonal and annual variation of LCC. This temporal variation of innate immunity was potentially due to physiological trade-offs or temporal variation in pathogen infections. The innate immunity, estimated as LCC, does not compensate for MHC diversity suggests that the immune system may function differently between vertebrates with different MHC organizations, with implications for the evolution of immune systems in different taxa.
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Affiliation(s)
- Yung Wa Sin
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire, OX13 5QL, United Kingdom
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
- Department of Organismic and Evolutionary Biology, Museum of Comparative Zoology, Harvard University, 26 Oxford Street, Cambridge, MA, 02138, United States of America
- * E-mail:
| | - Chris Newman
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire, OX13 5QL, United Kingdom
| | - Hannah L. Dugdale
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, PO Box 11103, 9700 CC, Groningen, Netherlands
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, United Kingdom
| | - Christina Buesching
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire, OX13 5QL, United Kingdom
| | - Maria-Elena Mannarelli
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, Norfolk, NR4 7TJ, United Kingdom
| | - Geetha Annavi
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire, OX13 5QL, United Kingdom
- Faculty of Science, Department of Biology, University of Putra Malaysia, UPM 43400, Serdang, Selangor, Malaysia
| | - Terry Burke
- NERC Biomolecular Analysis Facility, Department of Animal and Plant Sciences, University of Sheffield, Sheffield, S10 2TN, United Kingdom
| | - David W. Macdonald
- Wildlife Conservation Research Unit, Department of Zoology, University of Oxford, Recanati-Kaplan Centre, Tubney House, Abingdon Road, Tubney, Abingdon, Oxfordshire, OX13 5QL, United Kingdom
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Populations of the Lizard,Sceloporus occidentalis, that Differ in Melanization have Different Rates of Wound Healing. ACTA ACUST UNITED AC 2016; 325:491-500. [DOI: 10.1002/jez.2033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/23/2016] [Accepted: 06/28/2016] [Indexed: 11/07/2022]
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Innate immunity and testosterone rapidly respond to acute stress, but is corticosterone at the helm? J Comp Physiol B 2016; 186:907-18. [PMID: 27188192 DOI: 10.1007/s00360-016-0996-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Revised: 04/27/2016] [Accepted: 05/02/2016] [Indexed: 01/25/2023]
Abstract
When faced with a stressor, vertebrates can rapidly increase the secretion of glucocorticoids, which is thought to improve the chances of survival. Concurrent changes in other physiological systems, such as the reproductive endocrine or innate immune systems, have received less attention, particularly in wild vertebrates. It is often thought that glucocorticoids directly modulate immune performance during a stress response, but, in many species, androgens also rapidly respond to stress. However, to our knowledge, no study has simultaneously examined the interactions between the glucocorticoid, androgen, and innate immune responses to stress in a wild vertebrate. To address this issue, we tested the hypothesis that the change in plasma corticosterone (CORT) in response to the acute stress of capture and restraint is correlated with the concurrent changes in plasma testosterone (T) and innate immune performance (estimated by the capacity of plasma to agglutinate and lyse foreign cells) in the Abert's Towhee (Melozone aberti). Furthermore, to broaden the generality of the findings, we compared male and female towhees, as well as males from urban and non-urban populations. Acute stress increased plasma CORT, decreased plasma T in males, and decreased innate immune performance, but the increase in CORT during stress was not correlated with the corresponding decreases in either plasma T or innate immunity. By contrast, the plasma T stress response was positively correlated with the innate immune stress response. Collectively, our results challenge the proposition that the glucocorticoid stress response is correlated with the concurrent changes in plasma T, a key reproductive hormone, and innate immunity, as estimated by agglutination and lysis.
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Pedersen AL, Nelson LH, Saldanha CJ. Centrally Synthesized Estradiol Is a Potent Anti-Inflammatory in the Injured Zebra Finch Brain. Endocrinology 2016; 157:2041-51. [PMID: 26963472 PMCID: PMC4870876 DOI: 10.1210/en.2015-1991] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In homeotherms, injury to the brain, such as a penetrating wound, increases microglial cytokine expression and astroglial aromatase (estrogen synthase). In songbirds, injury-induced synthesis of estrogens is neuroprotective as aromatase inhibition and replacement with estradiol (E2) exacerbates and mitigates the extent of damage, respectively. The influence of induced aromatization on inflammation, however, remains unstudied. We hypothesized that injury-induced aromatization, via E2 synthesis, may affect neuroinflammation after a penetrating brain injury. Using adult zebra finches, we first documented an increase in the transcription of cytokines but not aromatase, 2 hours after the injury. Twenty-four hours after the injury, however, aromatase was dramatically elevated and cytokine expression had returned to baseline, suggesting that aromatization may be involved in the decrease of cytokines and neuroinflammation. In two subsequent experiments, we tested the influence of the inhibition of induced aromatization and aromatase inhibition with concomitant central E2 replacement on the transcription of the cytokines TNF-α, IL-1β, and IL-6, the enzyme cyclooxygenase-2 (cox-2), and its product prostaglandin E2 (PGE2). Administration of fadrozole, an aromatase inhibitor, caused a sustained elevation of IL-1β in females and TNF-α, cox-2, and PGE2 in both sexes. This prolonged neuroinflammation appears to be due to a failure to synthesize E2 locally because intracranial E2 replacement lowered IL-1β in females, TNF-α in males, and cox-2 and PGE2 in both sexes. IL-6 was not affected by injury, aromatase inhibition, or E2 replacement in either sex. These data suggest that E2 synthesis after a penetrating brain injury is a potent and inducible anti-inflammatory signal, with specific modulation of discrete cytokine signaling.
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Affiliation(s)
- Alyssa L Pedersen
- Department of Biology, Behavior, Cognition, and Neuroscience Program and The Center for Behavioral Neuroscience, American University, Washington, DC 20016
| | - Lars H Nelson
- Department of Biology, Behavior, Cognition, and Neuroscience Program and The Center for Behavioral Neuroscience, American University, Washington, DC 20016
| | - Colin J Saldanha
- Department of Biology, Behavior, Cognition, and Neuroscience Program and The Center for Behavioral Neuroscience, American University, Washington, DC 20016
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Calero-Riestra M, García JT. Sex-dependent differences in avian malaria prevalence and consequences of infections on nestling growth and adult condition in the Tawny pipit, Anthus campestris. Malar J 2016; 15:178. [PMID: 27001667 PMCID: PMC4802721 DOI: 10.1186/s12936-016-1220-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Accepted: 03/09/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Parasites play pivotal roles in host population dynamics and can have strong ecological impacts on hosts. Knowledge of the effects of parasites on hosts is often limited by the general observation of a fraction of individuals (mostly adults) within a population. The aim of this study was to assess the prevalence of malaria parasites in adult (≥ 1 year old) and nestling (7-11 day old) Tawny pipits Anthus campestris, to evaluate the influence of the host sex on parasite prevalence in both groups of age, and explore the association between infections and body condition (adults) and growth (nestlings). METHODS Two hundred Tawny pipits (105 adults and 95 nestlings) from one Spanish population were screened for avian malaria parasites (Haemoproteus and Plasmodium) using the polymerase chain reaction (PCR)-based methods. Body condition (body mass against a linear measure of size) was measured in adults and growth rate (daily mass gain) was calculated for nestlings. RESULTS The overall prevalence of infection was 46%. Sixteen different mitochondrial cytochrome b haplotypes of Plasmodium spp. and one Haemoproteus spp. haplotype were found. Malaria parasites were equally prevalent in nestlings and adults (45 and 46%, respectively). Males were more likely to be infected by parasites than females, and this sex-bias parasitism was evident in both adults and nestlings. Furthermore, a lower daily mass gain during nestling growth in males than in females following infections were found, whereas the effect of infections on body condition of adults was detrimental for females but not for males. CONCLUSIONS Age-specific differences in physiological trade-offs and ecological factors, such as nest predation would explain, at least in part, the observed host sex and age-related patterns in Tawny pipits.
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Affiliation(s)
- María Calero-Riestra
- Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo s/n, 13071, Ciudad Real, Spain
| | - Jesus T García
- Instituto de Investigación en Recursos Cinegéticos (IREC), CSIC-UCLM-JCCM, Ronda de Toledo s/n, 13071, Ciudad Real, Spain.
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Foo YZ, Nakagawa S, Rhodes G, Simmons LW. The effects of sex hormones on immune function: a meta-analysis. Biol Rev Camb Philos Soc 2016; 92:551-571. [DOI: 10.1111/brv.12243] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 10/30/2015] [Accepted: 11/06/2015] [Indexed: 11/30/2022]
Affiliation(s)
- Yong Zhi Foo
- ARC Centre of Excellence in Cognition and its Disorders, School of Psychology, University of Western Australia; 35 Stirling Hwy Crawley Western Australia 6009 Australia
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia; 35 Stirling Hwy Crawley Western Australia 6009 Australia
| | - Shinichi Nakagawa
- Department of Zoology; University of Otago; 340 Great King Street Dunedin 9016 New Zealand
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental Sciences, University of New South Wales; UNSW Sydney NSW 2052 Australia
| | - Gillian Rhodes
- ARC Centre of Excellence in Cognition and its Disorders, School of Psychology, University of Western Australia; 35 Stirling Hwy Crawley Western Australia 6009 Australia
| | - Leigh W. Simmons
- ARC Centre of Excellence in Cognition and its Disorders, School of Psychology, University of Western Australia; 35 Stirling Hwy Crawley Western Australia 6009 Australia
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia; 35 Stirling Hwy Crawley Western Australia 6009 Australia
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Sexually antagonistic selection during parental care is not generated by a testosterone-related intralocus sexual conflict-insights from full-sib comparisons. Sci Rep 2015; 5:17715. [PMID: 26625951 PMCID: PMC4667218 DOI: 10.1038/srep17715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Accepted: 11/04/2015] [Indexed: 01/05/2023] Open
Abstract
The evolution of shared male and female traits can be hampered if selection favours sex-specific optima. However, such genomic conflicts can be resolved when independent male and female mechanisms evolve. The existence, extent and consequences of conflict and/or conflict resolution are currently debated. Endocrinological traits like plasma testosterone (T) are suitable test cases, given their important role in mediating correlated traits, plus their opposing sex-specific fitness effects. We compared full-sibling (brother/sister) captive canaries to test for (1) sexually antagonistic selection characterized by contrasting fitness patterns within pairs of relatives, (2) intersexual genetic correlation of plasma T (h(²) = 0.41 ± 0.31) and (3) intralocus sexual conflict over T levels featured by distinct sex-specific fitness optima. We found potential for sexually antagonistic selection, since high fledgling mass was reached by either brothers or sisters, but not by both. We report a positive intersexual correlation for T, as a requirement for intralocus sexual conflict. However, high levels of T were associated with increased female and decreased male fitness (fledgling mass), which contrasts our expectations and challenges the hypothesis of intralocus sexual conflict driven by T. We hypothesize that behavioural and physiological trade-offs differ between sexes when raising offspring, driving T levels towards a state of monomorphism.
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Kawajiri M, Uchida K, Chiba H, Moriyama S, Yamahira K. Variation in the ontogeny of sex steroid levels between latitudinal populations of the medaka. ZOOLOGICAL LETTERS 2015; 1:31. [PMID: 26605076 PMCID: PMC4657280 DOI: 10.1186/s40851-015-0032-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 09/28/2015] [Indexed: 06/05/2023]
Abstract
INTRODUCTION Sex steroids mediate the expression of sexual dimorphism during ontogeny, and populations that differ in the magnitudes of sexual dimorphism may accordingly differ in the ontogenetic patterns of their sex steroid levels. The medaka, Oryzias latipes species complex, shows geographic variation in the magnitude of sexual dimorphism with respect to the lengths of their anal and dorsal fins; dimorphism is greater in low-latitude populations than in high-latitude populations. However, sexual differences in the ontogenetic dynamics of sex steroids, and its interpopulation variation, have not been examined. RESULTS We measured testosterone (T), estradiol-17β (E2), and 11-ketotestosterone (11-KT) concentrations throughout ontogeny of laboratory-reared fish from two latitudinal populations: Aomori (northern) and Okinawa (southern). In both populations, the levels of all three steroids were high during early ontogenetic stages and decreased with growth. After reaching about 15 mm in standard length, when sexual dimorphisms in fin lengths became apparent, steroid levels increased and tended to plateau. Sexual differences in the steroid levels were observed only in the later ontogenetic stages; T and 11-KT levels were higher in males, while E2 levels were higher in females. Accordingly, interpopulation differences also became clearer; the southern fish tended to show higher T levels and lower E2 levels than the northern fish. CONCLUSIONS The ontogenetic patterns of sex steroid levels paralleled the ontogeny of anal and dorsal fins in the two latitudinal populations, suggesting that interpopulation variation in the degree of sexual dimorphisms in fin lengths is mediated by sex steroid-dependent regulation of fin elongation.
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Affiliation(s)
- Maiko Kawajiri
- />Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, 903-0213 Japan
| | - Katsuhisa Uchida
- />Faculty of Agriculture, University of Miyazaki, Miyazaki, 889-2192 Japan
| | - Hiroaki Chiba
- />School of Marine Biosciences, Kitasato University, Kanagawa, 252-0373 Japan
| | - Shunsuke Moriyama
- />School of Marine Biosciences, Kitasato University, Kanagawa, 252-0373 Japan
| | - Kazunori Yamahira
- />Tropical Biosphere Research Center, University of the Ryukyus, Okinawa, 903-0213 Japan
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Muriel J, Salmón P, Nunez-Buiza A, de Salas F, Pérez-Rodríguez L, Puerta M, Gil D. Context-dependent effects of yolk androgens on nestling growth and immune function in a multibrooded passerine. J Evol Biol 2015; 28:1476-88. [PMID: 26079258 DOI: 10.1111/jeb.12668] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 06/08/2015] [Indexed: 01/08/2023]
Abstract
Female birds may adjust their offspring phenotype to the specific requirements of the environment by differential allocation of physiologically active substances into yolks, such as androgens. Yolk androgens have been shown to accelerate embryonic development, growth rate and competitive ability of nestlings, but they can also entail immunological costs. The balance between costs and benefits of androgen allocation is expected to depend on nestling environment. We tested this hypothesis in a multibrooded passerine, the spotless starling, Sturnus unicolor. We experimentally manipulated yolk androgen levels using a between-brood design and evaluated its effects on nestling development, survival and immune function. Both in first and replacement broods, the embryonic development period was shorter for androgen-treated chicks than controls, but there were no differences in second broods. In replacement broods, androgen-treated chicks were heavier and larger than those hatched from control eggs, but this effect was not observed in the other breeding attempts. Androgen exposure reduced survival with respect to controls only in second broods. Regarding immune function, we detected nonsignificant trends for androgen treatment to activate two important components of innate and adaptive immunity (IL-6 and Ig-A levels, respectively). Similarly, androgen-treated chicks showed greater lymphocyte proliferation than controls in the first brood and an opposite trend in the second brood. Our results indicate that yolk androgen effects on nestling development and immunity depend on the environmental conditions of each breeding attempt. Variation in maternal androgen allocation to eggs could be explained as the result of context-dependent optimal strategies to maximize offspring fitness.
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Affiliation(s)
- J Muriel
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain
| | - P Salmón
- Department of Biology, Evolutionary Ecology Unit, Lund University, Lund, Sweden
| | - A Nunez-Buiza
- Departamento de Fisiología Animal II, Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain
| | - F de Salas
- Departamento de Fisiología Animal II, Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain
| | - L Pérez-Rodríguez
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain.,Departamento de Ecología Evolutiva, Estación Biológica de Doñana (EBD-CSIC), Sevilla, Spain
| | - M Puerta
- Departamento de Fisiología Animal II, Facultad de Ciencias Biológicas, Universidad Complutense, Madrid, Spain
| | - D Gil
- Departamento de Ecología Evolutiva, Museo Nacional de Ciencias Naturales (MNCN-CSIC), Madrid, Spain
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Pavitt AT, Walling CA, Pemberton JM, Kruuk LEB. Heritability and cross-sex genetic correlations of early-life circulating testosterone levels in a wild mammal. Biol Lett 2015; 10:20140685. [PMID: 25428929 DOI: 10.1098/rsbl.2014.0685] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Testosterone is an important hormone that has been shown to have sex-specific links to fitness in numerous species. Although testosterone concentrations vary substantially between individuals in a population, little is known about its heritable genetic basis or between-sex genetic correlations that determine its evolutionary potential. We found circulating neonatal testosterone levels to be both heritable (0.160 ± 0.064 s.e.) and correlated between the sexes (0.942 ± 0.648 s.e.) in wild red deer calves (Cervus elaphus). This may have important evolutionary implications if, as in adults, the sexes have divergent optima for circulating testosterone levels.
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Affiliation(s)
- Alyson T Pavitt
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Craig A Walling
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Josephine M Pemberton
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Loeske E B Kruuk
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK Division of Evolution, Ecology and Genetics Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
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Vasilieva NY, Khrushchova AM, Shekarova ON, Rogovin KA. Testosterone and induced humoral immunity in male Campbell dwarf hamsters (Phodopus campbelli, Thomas, 1905, Rodentia, Cricetidae): Experimental manipulation of testosterone levels. BIOL BULL+ 2015. [DOI: 10.1134/s1062359015030139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Davies S, Cros T, Richard D, Meddle SL, Tsutsui K, Deviche P. Food availability, energetic constraints and reproductive development in a wild seasonally breeding songbird. Funct Ecol 2015; 29:1421-1434. [PMID: 27546946 PMCID: PMC4974902 DOI: 10.1111/1365-2435.12448] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Accepted: 03/23/2015] [Indexed: 11/28/2022]
Abstract
In many organisms, food availability is a proximate cue that synchronizes seasonal development of the reproductive system with optimal environmental conditions. Growth of the gonads and secondary sexual characteristics is orchestrated by the hypothalamic–pituitary–gonadal (HPG) axis. However, our understanding of the physiological mechanisms by which food availability modulates activity of the HPG axis is limited. It is thought that many factors, including energetic status, modulate seasonal reproductive activation. We tested the hypothesis that food availability modulates the activity of the HPG axis in a songbird. Specifically, we food‐restricted captive adult male Abert's Towhees Melozone aberti for 2 or 4 weeks during photoinduced reproductive development. A third group (control) received ad libitum food throughout. We measured multiple aspects of the reproductive system including endocrine activity of all three levels of the HPG axis [i.e. hypothalamic gonadotropin‐releasing hormone‐I (GnRH‐I), plasma luteinizing hormone (LH) and testosterone (T)], and gonad morphology. Furthermore, because gonadotropin‐inhibitory hormone (GnIH) and neuropeptide Y (NPY; a potent orexigenic peptide) potentially integrate information on food availability into seasonal reproductive development, we also measured the brain levels of these peptides. At the hypothalamic level, we detected no effect of food restriction on immunoreactive (ir) GnRH‐I, but the duration of food restriction was inversely related to the size of ir‐GnIH perikarya. Furthermore, the number of ir‐NPY cells was higher in food‐restricted than control birds. Food restriction did not influence photoinduced testicular growth, but decreased plasma LH and T, and width of the cloacal protuberance, an androgen‐sensitive secondary sexual characteristic. Returning birds to ad libitum food availability had no effect on plasma LH or T, but caused the cloacal protuberance to rapidly increase in size to that of ad libitum‐fed birds. Our results support the tenet that food availability modulates photoinduced reproductive activation. However, they also suggest that this modulation is complex and depends upon the level of the HPG axis considered. At the hypothalamic level, our results are consistent with a role for the GnIH and NPY systems in integrating information on energetic status. There also appears to be a role for endocrine function at the anterior pituitary gland and testicular levels in modulating reproductive development in the light of energetic status and independently of testicular growth.
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Affiliation(s)
- Scott Davies
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA; Present address: Department of Biological Sciences Virginia Tech Blacksburg Virginia 24061USA
| | - Thomas Cros
- Faculté des Sciences Fondamentales et Appliquées Université de Poitiers Poitiers 86022 France
| | - Damien Richard
- Faculté des Sciences Fondamentales et Appliquées Université de Poitiers Poitiers 86022 France
| | - Simone L Meddle
- The Roslin Institute The Royal (Dick) School of Veterinary Studies The University of Edinburgh Easter Bush Midlothian EH25 9RG UK
| | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences Department of Biology and Center for Medical Life Science Waseda University Tokyo 162-8480 Japan
| | - Pierre Deviche
- School of Life Sciences Arizona State University Tempe Arizona 85287 USA
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Desprat JL, Lengagne T, Dumet A, Desouhant E, Mondy N. Immunocompetence handicap hypothesis in tree frog: trade-off between sexual signals and immunity? Behav Ecol 2015. [DOI: 10.1093/beheco/arv057] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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