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Cruz-Cano NB, Sánchez-Rivera UÁ, Álvarez-Rodríguez C, Dávila-Govantes R, Cárdenas-León M, Martínez-Torres M. Sex steroids are correlated with environmental factors and body condition during the reproductive cycle in females of the lizard Sceloporus torquatus. Gen Comp Endocrinol 2021; 314:113921. [PMID: 34606744 DOI: 10.1016/j.ygcen.2021.113921] [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: 11/10/2020] [Revised: 09/25/2021] [Accepted: 09/29/2021] [Indexed: 12/06/2022]
Abstract
Reproduction is regulated by multiple factors that influence physiology and behavior to ensure the continuity of species. However, more work is needed to examine the complex relationships between environmental factors and endocrine transducers that modulate reproductive cycles, particularly in lizards. Here, we aimed to characterize the variation in plasma sex steroid levels in different stages of the reproductive cycle in the lizard Sceloporus torquatus and assess whether sex steroid levels were related to environmental factors (temperature, photoperiod, precipitation, and relative humidity) and body condition. Plasma concentrations of estradiol (E2) and progesterone (P4) from blood samples were quantified by enzyme-linked immunosorbent assay (ELISA) and radioimmunoanalysis (RIA), respectively. Our results indicate that sex steroid concentrations were positively related to follicular development but negatively related to temperature and precipitation. E2 increased as the follicles grew, and its concentrations were highest in the preovulatory phase. P4 showed a similar pattern and persisted during pregnancy. Changes in body condition were non-significant and mainly unrelated to the reproductive stage and plasma sex steroids. Our findings indicate that sex steroids change depending on the season and reproductive stage. We observed high concentrations of E2 and P4 in the late vitellogenic and preovulatory stages, probably because of their role in promoting vitellogenesis and ovulation. Additionally, we observed that follicular development is correlated with temperature and photoperiod. To better understand the mechanisms underlying reproduction, future studies of captive populations where environmental factors can be manipulated are needed.
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Affiliation(s)
- Norma Berenice Cruz-Cano
- Posgrado en Ciencias Biológicas, Universidad Nacional Autónoma de México, Edificio D, 1° Piso, Circuito de Posgrados, Ciudad Universitaria, Coyoacán, Ciudad de México, México; Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México.
| | - Uriel Ángel Sánchez-Rivera
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Carmen Álvarez-Rodríguez
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Rodrigo Dávila-Govantes
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México
| | - Mario Cárdenas-León
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México; Laboratorio de Hormonas Proteicas, Departamento de Biología de la Reproducción, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No. 15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, C.P. 14080, Ciudad de México, México
| | - Martín Martínez-Torres
- Laboratorio de Biología de la Reproducción, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Avenida de los Barrios s/n, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54110, México.
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Josimovich JM, Falk BG, Grajal-Puche A, Hanslowe EB, Bartoszek IA, Reed RN, Currylow AF. Clutch may predict growth of hatchling Burmese pythons better than food availability or sex. Biol Open 2021; 10:273482. [PMID: 34796905 PMCID: PMC8609237 DOI: 10.1242/bio.058739] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 10/21/2021] [Indexed: 12/20/2022] Open
Abstract
Identifying which environmental and genetic factors affect growth pattern phenotypes can help biologists predict how organisms distribute finite energy resources in response to varying environmental conditions and physiological states. This information may be useful for monitoring and managing populations of cryptic, endangered, and invasive species. Consequently, we assessed the effects of food availability, clutch, and sex on the growth of invasive Burmese pythons (Python bivittatus Kuhl) from the Greater Everglades Ecosystem in Florida, USA. Though little is known from the wild, Burmese pythons have been physiological model organisms for decades, with most experimental research sourcing individuals from the pet trade. Here, we used 60 hatchlings collected as eggs from the nests of two wild pythons, assigned them to High or Low feeding treatments, and monitored growth and meal consumption for 12 weeks, a period when pythons are thought to grow very rapidly. None of the 30 hatchlings that were offered food prior to their fourth week post-hatching consumed it, presumably because they were relying on internal yolk stores. Although only two clutches were used in the experiment, we found that nearly all phenotypic variation was explained by clutch rather than feeding treatment or sex. Hatchlings from clutch 1 (C1) grew faster and were longer, heavier, in better body condition, ate more frequently, and were bolder than hatchlings from clutch 2 (C2), regardless of food availability. On average, C1 and C2 hatchling snout-vent length (SVL) and weight grew 0.15 cm d−1 and 0.10 cm d−1, and 0.20 g d−1 and 0.03 g d−1, respectively. Additional research may be warranted to determine whether these effects remain with larger clutch sample sizes and to identify the underlying mechanisms and fitness implications of this variation to help inform risk assessments and management. This article has an associated First Person interview with the first author of the paper. Summary: Hatchling pythons from an invasive population displayed substantial phenotypic variation in morphometrics, growth rates, and behaviors. This information may be useful for managing populations of cryptic, endangered, and invasive species.
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Affiliation(s)
- Jillian M Josimovich
- U.S. Geological Survey, Fort Collins Science Center - South Florida Field Station, 40001 SR 9336, Homestead, FL 33034, USA
| | - Bryan G Falk
- U.S. Geological Survey, Fort Collins Science Center - South Florida Field Station, 40001 SR 9336, Homestead, FL 33034, USA
| | - Alejandro Grajal-Puche
- U.S. Geological Survey, Fort Collins Science Center - South Florida Field Station, 40001 SR 9336, Homestead, FL 33034, USA
| | - Emma B Hanslowe
- U.S. Geological Survey, Fort Collins Science Center - South Florida Field Station, 40001 SR 9336, Homestead, FL 33034, USA
| | | | - Robert N Reed
- U.S. Geological Survey, Fort Collins Science Center, Fort Collins, CO 80526, USA
| | - Andrea F Currylow
- U.S. Geological Survey, Fort Collins Science Center - South Florida Field Station, 40001 SR 9336, Homestead, FL 33034, USA
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Donini J, Lechowicz C, Valverde R. Comparisons of Summer and Winter Patterns in Ovarian Development, Plasma Vitellogenin, and Sex Steroids in Female Diamondback Terrapins (Malaclemys terrapin) in Southern Florida. CHELONIAN CONSERVATION AND BIOLOGY 2018. [DOI: 10.2744/ccb-1310.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jordan Donini
- Department of Biological Sciences, Southeastern Louisiana University, 808 North Pine Street, Hammond
| | - Chris Lechowicz
- Wildlife and Habitat Management Program, Sanibel Captiva Conservation Foundation, 3333 Sanibel Capti
| | - Roldán Valverde
- Department of Biological Sciences, Southeastern Louisiana University, 808 North Pine Street, Hammond
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Van Dyke JU, Griffith OW. Mechanisms of reproductive allocation as drivers of developmental plasticity in reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:275-286. [PMID: 29733527 DOI: 10.1002/jez.2165] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 04/09/2018] [Accepted: 04/13/2018] [Indexed: 12/30/2022]
Abstract
Developmental plasticity in offspring phenotype occurs as a result of the environmental conditions embryos experience during development. The nutritional environment provided to a fetus is an important source of developmental plasticity. Reptiles are a particularly interesting system to study this plasticity because of their varied routes of maternal nutrient allocation to reproduction. Most reptiles provide their offspring with all or most of the nutrients they require in egg yolk (lecithotrophy) while viviparous reptiles also provide their offspring with nutrients via a placenta (placentotrophy). We review the ways in which both lecithotrophy and placentotrophy can lead to differences in the nutrients embryonic reptiles receive, and discuss how these differences lead to developmental plasticity in offspring phenotype. We finish by reviewing the ecological and conservation consequences of nutritional-driven developmental plasticity in reptiles. If nutritional-driven developmental plasticity has fitness consequences, then understanding the basis of this plasticity has exciting potential to identify how reptile recruitment is affected by environmental changes in food supply. Such knowledge is critical to our ability to protect taxa threatened by environmental change.
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Affiliation(s)
- James U Van Dyke
- School of Environmental Sciences, Institute of Land, Water & Society, Charles Sturt University, Albury, NSW, Australia
| | - Oliver W Griffith
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut.,Yale Systems Biology Institute, Yale University, West Haven, Connecticut
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Currylow AFT, Rafeliarisoa TH, Louis EE, Stanford CB, Randrianjafizanaka ST, Chinn SM, Crocker DE. Characterization of seasonal reproductive and stress steroid hormones in wild Radiated Tortoises, Astrochelys radiata. Gen Comp Endocrinol 2017; 253:70-78. [PMID: 28888695 DOI: 10.1016/j.ygcen.2017.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 08/29/2017] [Accepted: 09/03/2017] [Indexed: 10/18/2022]
Abstract
The critically endangered Radiated Tortoise (Astrochelys radiata) is endemic to the southern coastlines of Madagascar. Once common, wild populations of this tortoise have undergone dramatic declines in recent years. Although there have been studies documenting reproductive activities, reproductive physiological parameters are unknown yet may be crucial in the recovery of the species. Over four research seasons in remote field locations native to A. radiata, we surveyed for, radio-tracked, and sampled wild, free ranging tortoises. We sampled and measured stress and reproductive parameters (corticosterone [CORT], testosterone [T], estradiol-17β [E2], and progesterone [P]) in 311 plasma samples from 203 wild A. radiata, capturing their active period. Generally, hormone concentrations were associated with body condition, temperature, and humidity. There was wide variation in CORT that varied monthly and by group. Juvenile tortoises maintained more than twice the mean basal CORT concentrations than either adult sex, with the most dramatic distinctions in the middle of the wet season. For adult sex hormones, the last months of the dry season and into the wet season when ground humidities are low and just begin to rise prior to temperature declines, male T concentrations gradually increased to a peak before returning to near undetectable values into the dry season. We had limited data for T concentrations in females, but found average T concentrations were much lower than in males and positively correlated with larger female home range sizes. For female hormone cycles, E2 also peaked in the early 1/3 of the wet season along with male T, and was followed by an uptick in P which correlates to the putative ovulatory cycle. Females tracked over four years showed variation in patterns of P, indicating that number and frequency of clutches vary. Our results suggest that 1) there is high species plasticity in response to stress; 2) A. radiata reproductive cycling is somewhat dissociated with courtship timing and is instead triggered by environmental cues; and 3) individual female reproductive output is irregular. This study is oone of the first to document and describe multi-year seasonal stress and reproductive hormones in a free-ranging Malagasy chelonian. These data may be used to identify key high-production habitats for conservation, and aide in captive management and reproduction in assurance colonies for species health and survival.
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Affiliation(s)
- Andrea F T Currylow
- Integrative and Evolutionary Biology, University of Southern California, Los Angeles, CA, USA.
| | - Tsilavo H Rafeliarisoa
- Animal Biology Department, University of Antananarivo, Antananarivo, Madagascar; Madagascar Biodiversity Partnership; Conservation Genetics Department, Omaha's Henry Doorly Zoo and Aquarium, Omaha, NE, USA
| | - Edward E Louis
- Madagascar Biodiversity Partnership; Conservation Genetics Department, Omaha's Henry Doorly Zoo and Aquarium, Omaha, NE, USA
| | - Craig B Stanford
- Integrative and Evolutionary Biology, University of Southern California, Los Angeles, CA, USA; Herpetology Section, Los Angeles County Natural History Museum, Los Angeles, CA, USA
| | | | - Sarah M Chinn
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
| | - Daniel E Crocker
- Department of Biology, Sonoma State University, Rohnert Park, CA, USA
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