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Keogh MJ, Nicholson KL, Skinner JP. Relationships between age, diet, and stress-related hormones and reproduction in American marten ( Martes americana). J Mammal 2022. [DOI: 10.1093/jmammal/gyac067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
American marten (Martes americana) in Interior Alaska are at the northwestern limit of their North American range. To investigate factors that may be associated with reproduction we determined the cementum age and the presence or absence of blastocysts in 118 female martens for 3 years (2012, 2014, and 2016) in two regions. For each marten we collected fur samples and measured steroid hormone concentrations (cortisol, testosterone, and progesterone) and stable isotopes (δ15N and δ13C values, a proxy for diet). These parameters reflect the diet and endocrine activity between June and October when fur is grown. We also collected two claws from a subset of 39 female marten from one region in 2012 and 2014. Progesterone concentrations were measured in one whole claw and from a second claw divided into proximal (recent growth) and distal sections. Differences in the probability of blastocysts being present were associated with geographic region and sample year suggesting that reproduction in female marten varies on a fine scale. We found the that presence of blastocysts was positively associated with marten age and δ15N values in fur but negatively associated with fur cortisol concentrations. These findings suggest that the likelihood a female marten will reproduce in a given year is influenced, in part, by the proportion of protein in their diet and stressors encountered during late summer and fall, months before active gestation begins.
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Affiliation(s)
- Mandy J Keogh
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Douglas, Alaska , USA
| | - Kerry L Nicholson
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Fairbanks, Alaska , USA
| | - John P Skinner
- Division of Wildlife Conservation, Alaska Department of Fish and Game , Anchorage, Alaska , USA
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Wilson KS, Li D, Valentine I, McNeilly A, Girling S, Li R, Zhou Y, Vanhaecke L, Colin Duncan W, Wauters J. The novel use of urinary androgens to optimise detection of the fertile window in giant pandas. REPRODUCTION AND FERTILITY 2022; 3:122-132. [PMID: 35949393 PMCID: PMC9354564 DOI: 10.1530/raf-22-0031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 06/30/2022] [Indexed: 12/03/2022] Open
Abstract
Abstract Giant pandas are mono-estrus seasonal breeders, with the breeding season typically occurring in the spring. Successful fertilization is followed by an embryonic diapause, of variable length, with birth in the late summer/autumn. There is a need for additional understanding of giant panda reproductive physiology, and the development of enhanced biomarkers for impending proestrus and peak fertility. We aimed to determine the utility of non-invasive androgen measurements in the detection of both proestrus and estrus. Urine from 20 cycles (-40 days to +10 days from peak estrus) from 5 female giant pandas was analyzed for estrogen, progestogens and androgens (via testosterone and DHEA assays), and hormone concentrations were corrected against urinary specific gravity. Across proestrus, estrogens increased while progestogens and androgens decreased - at the point of entry into proestrus, androgens (as detected by the testosterone assay) decreased prior to progestogens and gave 4 days advanced warning of proestrus. At the time of peak estrus, androgens (as detected by the DHEA assay) were significantly increased at the time of the decrease in estrogen metabolites from the peak, acting as an alternative confirmatory indicator of the fertile window. This novel finding allows for enlargement of the preparative window for captive breeding and facilitates panda management within breeding programmes. Androgens allow an enhanced monitoring of giant panda estrus, not only advancing the warning of impending proestrus, but also prospectively identifying peak fertility. Lay summary Giant pandas have one chance at pregnancy per year. The 2-day fertile window timing varies by year and panda. This is monitored by measuring the level of estrogens in the urine, which increase, indicating an upcoming fertile period. After 1-2 weeks of increase, estrogens peak and fall, marking the optimal fertile time. We tested other hormones to see if we can predict the fertile window in advance, and the specific fertile time with more accuracy. In 20 breeding seasons from 5 females, we found androgens, usually thought of as male hormones, had an important role. Testosterone gives 4 days advanced warning of estrogens increasing. DHEA identified peak estrogen and the fertile time before needing to see a confirmed decrease in estrogen itself. Therefore, androgens help improve monitoring of the giant panda breeding season, giving early warning of fertility, key in facilitating captive breeding and giant panda conservation.
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Affiliation(s)
- Kirsten S Wilson
- MRC Centre for Reproductive Health, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Desheng Li
- Key Laboratory of SFGA on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Centre for the Giant Panda (CCRCGP), DuJiangYan City, Sichuan Province, China
| | | | - Alan McNeilly
- MRC Centre for Reproductive Health, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | | | - Rengui Li
- Key Laboratory of SFGA on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Centre for the Giant Panda (CCRCGP), DuJiangYan City, Sichuan Province, China
| | - Yingmin Zhou
- Key Laboratory of SFGA on Conservation Biology of Rare Animals in The Giant Panda National Park, China Conservation and Research Centre for the Giant Panda (CCRCGP), DuJiangYan City, Sichuan Province, China
| | - Lynn Vanhaecke
- Laboratory of Integrative Metabolomics, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - W Colin Duncan
- MRC Centre for Reproductive Health, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, UK
| | - Jella Wauters
- Laboratory of Integrative Metabolomics, Department of Translational Physiology, Infectiology and Public Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Leibniz Institute for Zoo and Wildlife Research, Department Reproduction Biology, Berlin, Germany
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Boonstra R, Gandhi N, Kraushaar A, Galbreath K. From Habitat to Hormones: Year-around territorial behavior in rock-dwelling but not in forest and grassland lagomorphs and the role of DHEA. Horm Behav 2022; 142:105179. [PMID: 35477059 DOI: 10.1016/j.yhbeh.2022.105179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 04/16/2022] [Accepted: 04/18/2022] [Indexed: 11/25/2022]
Abstract
Year-around defense of extremely patchy habitat may require hormones that drive territorial behavior, but have no other costly physiological effects. The American pika (Ochotona princeps), but not the snowshoe hare (Lepus americanus) nor the eastern cottontail rabbit (Sylvilagus floridanus), exhibits this behavior. The former engages in contest competition against all individuals independent of sex to protect its territory in highly fragmented patches on mountain talus slopes; the latter in scramble competition in more continuous forests, grasslands, and shrublands. The hormonal basis for this difference in lagomorphs is unknown. Dehydroepiandrosterone is a prohormone produced by the zona reticularis of the adrenal cortex. It has no effect on aggressive behavior until converted in the brain to estrogen. We assessed levels (DHEA-S plus DHEA) in all species collected in the wild. In nonbreeding pikas, levels were 256 times higher than in hares and 22 times higher than in rabbits. Within species, females and males had similar levels. The proportion of the adrenal cortex devoted to the zona reticularis was significantly larger in pikas than in hares or rabbits. Our evidence is consistent with the hypothesis that dehydroepiandrosterone drives this individual-based, year-around territoriality in pikas. We propose a definitive experiment to determine this and recommend comparative studies in central Asia where there is high diversity of pika species whose behavior ranges from individual-based territoriality to colonial. Thus, we speculate that the wild American pika has the adrenal-brain nexus for all seasons and is an excellent model to understand how habitat drives the hormonal control of spacing behavior.
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Affiliation(s)
- Rudy Boonstra
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada.
| | - Nisha Gandhi
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario M1C 1A4, Canada
| | - Alec Kraushaar
- Department of Biology, Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855, USA
| | - Kurt Galbreath
- Department of Biology, Northern Michigan University, 1401 Presque Isle Ave, Marquette, MI 49855, USA
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Gese EM, Terletzky PA. Space use in free-ranging canids: are gonadal hormones required for territory maintenance? CAN J ZOOL 2021. [DOI: 10.1139/cjz-2021-0085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Fertility control among carnivores has been used to reduce depredations on livestock and wild neonates, population control, modify behavior, inhibit genetic introgression, and reduce human–wildlife conflicts. Although there is considerable knowledge on techniques to sterilize carnivores, there is little information concerning how the absence of gonadal hormones influences behavior, space use, and survival of wild canids. We examined territorial fidelity, home-range size and overlap, and survival of 179 surgically sterilized free-ranging canids (124 coyotes (Canis latrans Say, 1823), 55 coyote – red wolf (Canis rufus Audubon and Bachman, 1851) hybrids) with gonadal hormones present (tubal-ligated females (n = 70), vasectomized males (n = 73)) versus absent (spayed females (n = 22), neutered males (n = 14)). The absence of gonadal hormones did not influence annual home-range size and home-range overlap, territory fidelity, and annual survival rates. Additionally, no differences were detected across sexes and hormonal treatments in annual home-range size, percent home-range overlap, annual home-range residency rates, and annual survival rates. Methods of fertility control that do not keep gonadal organs intact may prove useful for management without concern for changes in behavior, mainly territoriality, space use, and survival.
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Affiliation(s)
- Eric M. Gese
- U.S. Department of Agriculture, Wildlife Services, National Wildlife Research Center, Department of Wildland Resources, Utah State University, Logan, UT 84322, USA
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