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Brown GP, Shine R. Do Microbiota in the Soil Affect Embryonic Development and Immunocompetence in Hatchling Reptiles? Front Ecol Evol 2022. [DOI: 10.3389/fevo.2021.780456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reptile eggs develop in intimate association with microbiota in the soil, raising the possibility that embryogenesis may be affected by shifts in soil microbiota caused by anthropogenic disturbance, translocation of eggs for conservation purposes, or laboratory incubation in sterile media. To test this idea we incubated eggs of keelback snakes (Tropidonophis mairii, Colubridae) in untreated versus autoclaved soil, and injected lipopolysaccharide (LPS) into the egg to induce an immune response in the embryo. Neither treatment modified hatching success, water uptake, incubation period, or white-blood-cell profiles, but both treatments affected hatchling size. Eggs incubated on autoclaved soil produced smaller hatchlings than did eggs on untreated soil, suggesting that heat and/or pressure treatment decrease the soil’s suitability for incubation. Injection of LPS reduced hatchling size, suggesting that the presence of pathogen cues disrupts embryogenesis, possibly by initiating immune reactions unassociated with white-blood-cell profiles. Smaller neonates had higher ratios of heterophils to leucocytes, consistent with higher stress in smaller snakes, or body-size effects on investment into different types of immune cells. Microbiota in the incubation medium thus can affect viability-relevant phenotypic traits of hatchling reptiles. We need further studies to explore the complex mechanisms and impacts of environmental conditions on reptilian embryogenesis.
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2
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Yu TL, Wang G, Vasconcellos MM, Li YJ. Evolution of sexual dimorphism in an endemic toad of the Qinghai–Tibet plateau fails to obey Rensch’s rule. J ZOOL SYST EVOL RES 2021. [DOI: 10.1111/jzs.12554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Tong Lei Yu
- College of Life Science Xinyang Normal University Xinyang China
| | - Gang Wang
- College of Chemistry and Life Science Chengdu Normal University Chengdu China
| | | | - Yu Jie Li
- College of Life Science China West Normal University Nanchong China
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Taggart PL, Morris S, Caraguel CGB. The impact of PIT tags on the growth and survival of pythons is insignificant in randomised controlled trial. PeerJ 2021; 9:e11531. [PMID: 34249487 PMCID: PMC8254472 DOI: 10.7717/peerj.11531] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/06/2021] [Indexed: 11/22/2022] Open
Abstract
Individual identification is fundamental to the study of captive and wild animals but can have adverse impacts if the method of identification is inappropriate for the species or question of interest. We conducted a randomised controlled trial to test whether passive integrated transponder (PIT) tags reduced the growth or survival of pythons. We randomly allocated 200 captive-bred Burmese python (Python bivittatus) hatchlings into two groups, tagged versus untagged. Hatchlings were individually identified using a combination of PIT tags and unique colour patterns, and their mass, snout-vent length (SVL) and body condition measured at 9, 73, 134, 220, 292 and 385 days of age. We recorded the date of all mortalities. Python morphometrics and their rate of change increased or fluctuated non-linearly with age. The impact of PIT tagging on python body mass and body mass growth over the 376 day study period was insignificant. PIT tagging additionally had an insignificant impact on python survival. However, we found minor differences in SVL growth between tagged and untagged pythons. These differences peaked at approximately 0.5 mm/day and appeared to drive similar, but more pronounced, differences between tagged and untagged pythons in their rate of change in body condition; peaking at approximately 3–4 g/day. While we cannot be certain that these small differences are, or are not, biologically meaningful, they nonetheless appear to be short-term and readily resolved. Unsurprisingly, the strongest driver of python growth was their age, with growth rapidly increasing or highest amongst younger snakes for all measures of size. Python sex was associated with their body mass and survival, with higher mass but lower survival amongst females. Python size at hatching did not impact on their growth or survival. Our results confirm that PIT tags are a valuable and effective tool for the identification and tracking of captive pythons, and snakes generally, and meet high safety and animal welfare standards.
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Affiliation(s)
- Patrick L Taggart
- School of Animal and Veterinary Science, The University of Adelaide, Roseworthy, SA, Australia.,Vertebrate Pest Research Unit, NSW Department of Primary Industries, Queanbeyan, NSW, Australia
| | - Stephen Morris
- NSW Department of Primary Industries, Wollonbar, NSW, Australia
| | - Charles G B Caraguel
- School of Animal and Veterinary Science, The University of Adelaide, Roseworthy, SA, Australia
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4
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Bury S. Sex-specific growth is mirrored in feeding rate but not moulting frequency in a sexually dimorphic snake. Naturwissenschaften 2021; 108:6. [PMID: 33415456 DOI: 10.1007/s00114-020-01712-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 11/06/2020] [Accepted: 11/16/2020] [Indexed: 11/30/2022]
Abstract
Sexual size dimorphism (SSD), commonly observed in snakes, may arise from a different growth rate between the sexes. This indicates a sex-specific resource intake that is in fact observable in free-living snakes. It is not so well known whether the sexes can express differential feeding rates under conditions unconstrained by spatial accessibility, competition, etc. Here, I studied sex-specific variation in growth, its correlate-moulting frequency, and feeding rate in a captive group of sexually dimorphic banded water snakes (Nerodia fasciata) with access to food unconstrained by predation, competition or space. I showed that the sexes did indeed differ in relative mass growth in that females grew faster than males (p = 0.02), but such differences were not apparent in the moulting rate (p = 0.19). Such differential growth was mirrored in the sex-specific feeding rate, with females ingesting a larger number of meals than males (p = 0.004). Such variation in feeding rate may be governed by an individual's energy expenditure and can be interpreted as a behavioural tendency that contributes to SSD development, independently of other behavioural characteristics. Sex-specific resource demands may drive the differential effects of increasing resource scarcity on both sexes.
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Affiliation(s)
- Stanisław Bury
- Department of Comparative Anatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Gronostajowa 9, 30-387, Kraków, Poland. .,Institute of Environmental Sciences, Jagiellonian University, Gronostajowa 7, 30-387, Kraków, Poland. .,NATRIX Herpetological Association, Legnicka 65, 54-206, Wrocław, Poland.
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Jaramillo-Alba JL, Pérez-Mendoza HA, de la Vega-Pérez AHD, Akcali CK. Do Reproductive Costs Affect Adult Survival in Mexican Dusky Rattlesnakes? A Test Using Mark–Recapture Data. HERPETOLOGICA 2020. [DOI: 10.1655/herpetologica-d-19-00013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- José Luis Jaramillo-Alba
- Laboratorio de Ecología Evolutiva de Anfibios y Reptiles, Facultad de Estudios Superiores Iztacala, UNAM, Avenida de Los Barrios número 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54090, México
| | - Hibraim Adán Pérez-Mendoza
- Laboratorio de Ecología Evolutiva de Anfibios y Reptiles, Facultad de Estudios Superiores Iztacala, UNAM, Avenida de Los Barrios número 1, Los Reyes Iztacala, Tlalnepantla, Estado de México, C.P. 54090, México
| | - Aníbal Helios Díaz de la Vega-Pérez
- Consejo Nacional de Ciencia y Tecnología–Centro Tlaxcala de Biología de la Conducta, Universidad Autónoma de Tlaxcala, km 1.5 Carretera Tlaxcala-Puebla, C.P. 90070, Tlaxcala, México
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García A, Siliceo-Cantero HH. Huracán Jova: efecto de un fenómeno meteorológico severo sobre lagartijas insulares en el occidente de México. REV MEX BIODIVERS 2019. [DOI: 10.22201/ib.20078706e.2019.90.2880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Su J, Hegab IM, Ji W, Nan Z. Function-related Drivers of Skull Morphometric Variation and Sexual Size Dimorphism in a Subterranean Rodent, Plateau Zokor ( Eospalax baileyi). Ecol Evol 2018; 8:4631-4643. [PMID: 29760903 PMCID: PMC5938458 DOI: 10.1002/ece3.3986] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/16/2018] [Accepted: 02/20/2018] [Indexed: 12/12/2022] Open
Abstract
Sexual dimorphism is prevalent in most living organisms. The difference in size between sexes of a given species is generally known as sexual size dimorphism (SSD). The magnitude of the SSD is determined by Rensch's rule where size dimorphism increases with increasing body size when the male is the larger sex and decreases with increasing average body size when the female is the larger sex. The unique underground environment that zokors (Eospalax baileyi) live under in the severe habitat of the Qinghai‐Tibetan Plateau (QTP) could create SSD selection pressures that may or may not be supported by Rensch's rule, making this scientific question worthy of investigation. In this study, we investigated the individual variation between sexes in body size and SSD of plateau zokors using measurements of 19 morphological traits. We also investigated the evolutionary mechanisms underlying SSD in plateau zokors. Moreover, we applied Rensch's rule to all extant zokor species. Our results showed male‐biased SSD in plateau zokors: The body‐ and head‐related measurements were greater in males than in females. Linear regression analysis between body length, body weight, and carcass weight showed significant relationships with some traits such as skull length, lower incisor length, and tympanic bulla width, which might support our prediction that males have faster growth rates than females. Further, the SSD pattern corroborated the assumption of Rensch's rule in plateau zokors but not in the other zokor species. Our findings suggest that the natural underground habitat and behavioral differences between sexes can generate selection pressures on male traits and contribute to the evolution of SSD in plateau zokors.
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Affiliation(s)
- Junhu Su
- State Key Laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and Technology Lanzhou University Lanzhou China.,College of Grassland Science Key Laboratory of Grassland Ecosystem (Ministry of Education) Gansu Agricultural University Lanzhou China.,Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity Gansu Agricultural University Lanzhou China
| | - Ibrahim M Hegab
- College of Grassland Science Key Laboratory of Grassland Ecosystem (Ministry of Education) Gansu Agricultural University Lanzhou China.,Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity Gansu Agricultural University Lanzhou China.,Faculty of Veterinary Medicine Department of Hygiene, Zoonosis and Animal Behavior & Management Suez Canal University Ismailia Egypt
| | - Weihong Ji
- Gansu Agricultural University-Massey University Research Centre for Grassland Biodiversity Gansu Agricultural University Lanzhou China.,Institute of Natural and Mathematical Sciences Massey University Auckland New Zealand
| | - Zhibiao Nan
- State Key Laboratory of Grassland Agro-ecosystems College of Pastoral Agriculture Science and Technology Lanzhou University Lanzhou China
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Brown GP, Shine R. Immune configuration in hatchling snakes is affected by incubation moisture, and is linked to subsequent growth and survival in the field. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:222-229. [DOI: 10.1002/jez.2154] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/05/2018] [Accepted: 03/07/2018] [Indexed: 01/22/2023]
Affiliation(s)
- Gregory P. Brown
- School of Life and Environmental Sciences University of Sydney Sydney, NSW Australia
| | - Richard Shine
- School of Life and Environmental Sciences University of Sydney Sydney, NSW Australia
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The causes and ecological correlates of head scale asymmetry and fragmentation in a tropical snake. Sci Rep 2017; 7:11363. [PMID: 28900296 PMCID: PMC5595785 DOI: 10.1038/s41598-017-11768-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 08/30/2017] [Indexed: 11/15/2022] Open
Abstract
The challenge of identifying the proximate causes and ecological consequences of phenotypic variation can be facilitated by studying traits that are usually but not always bilaterally symmetrical; deviations from symmetry likely reflect disrupted embryogenesis. Based on a 19-year mark-recapture study of >1300 slatey-grey snakes (Stegonotus cucullatus) in tropical Australia, and incubation of >700 eggs, we document developmental and ecological correlates of two morphological traits: asymmetry and fragmentation of head scales. Asymmetry was directional (more scales on the left side) and was higher in individuals with lower heterozygosity, but was not heritable. In contrast, fragmentation was heritable and was higher in females than males. Both scale asymmetry and fragmentation were increased by rapid embryogenesis but were not affected by hydric conditions during incubation. Snakes with asymmetry and fragmentation exhibited slightly lower survival and increased (sex-specific) movements, and females with more scale fragmentation produced smaller eggs. Counterintuitively, snakes with more asymmetry had higher growth rates (possibly reflecting trade-offs with other traits), and snakes with more fragmentation had fewer parasites (possibly due to lower feeding rates). Our data paint an unusually detailed picture of the complex genetic and environmental factors that, by disrupting early embryonic development, generate variations in morphology that have detectable correlations with ecological performance.
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