1
|
House-warming: Wild king cobra nests have thermal regimes that positively affect hatching success and hatchling size. J Therm Biol 2023; 112:103468. [PMID: 36796913 DOI: 10.1016/j.jtherbio.2023.103468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 01/05/2023] [Accepted: 01/06/2023] [Indexed: 01/09/2023]
Abstract
Incubation temperature in nests of oviparous reptiles affects reproductive success indicators, including hatching time and success, offspring size, fitness, and behaviour. The female king cobra builds an above ground nest to incubate and protect its eggs. However, it is not clear how thermal regimes inside king cobra nests respond to external environmental temperature regimes, especially in subtropical regions that witness high diel and seasonal temperature fluctuations. To better understand the relationship between inside nest temperatures and hatching outcomes for this snake, we monitored the thermal regimes of 25 natural king cobra nests in the subtropical forests of the Western Himalayas in Uttarakhand state, northern India. We hypothesized that inside nest temperatures would be higher than outside (ambient) temperatures and that thermal regimes inside nests would affect hatching success and hatchling size. Internal and external temperatures at nest sites were measured every hour until hatching, via automatic data loggers. We then calculated hatching success of eggs and measured hatchling length and weight. Mean inside nest temperatures were consistently higher by about 3.0 °C than outside environmental temperatures. External temperature reduced with increasing elevation of nest sites and was the best determinant of inside nest temperature, which had a smaller range of variability. Physical characteristics of nests (size and leaf materials used) did not influence nest temperature significantly, but nest size was positively related to clutch size. Mean inside nest temperature was the best predictor of hatching success. Average daily minimum nest temperature, which indicates a possible lower threshold for thermal tolerance by eggs, was also correlated positively with hatching success. Mean daily maximum temperature was a significant predictor of mean length of hatchlings, but not of mean hatchling weight. Our study provides unequivocal evidence for the critical thermal benefits of king cobra nests for increased reproductive success, in subtropical environments with lower and sharply fluctuating temperature regimes.
Collapse
|
2
|
Streeting LM, Bower DS, Dillon ML, Spark P, Gough M, Skidmore A, McDonald PG, Delaney H, Burns A, Watson S, Dissanayake DSB, Georges A, McKnight DT. Optimising the hatching success of artificially incubated eggs for use in a conservation program for the western saw-shelled turtle (. AUST J ZOOL 2022. [DOI: 10.1071/zo22014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Artificial incubation of eggs and the release of hatchlings into the wild is a common conservation intervention designed to augment threatened turtle populations. We investigate a range of incubation temperatures to establish an optimal temperature for maximum hatching success of western saw-shelled turtle (Myuchelys bellii) eggs. We report on the influence of incubation temperature on incubation duration and hatching success and describe two experimental incubation methods which, for the same incubation temperature (27°C), resulted in 77% and 97% hatching success, respectively. Eggs were incubated at constant temperatures (27°C, 28°C and 29°C) to determine the influence of temperature on incubation period, hatchling morphology and external residual yolk. Incubation duration was negatively correlated with incubation temperature. We report on the morphology of eggs and hatchlings and show that their dimensions are positively correlated with maternal adult size and mass. A constant incubation temperature of 27°C produced the highest hatching success and smallest external residual yolk on hatching and is therefore recommended for incubation of eggs for population reinforcement programs. Our study is the first to optimise artificial incubation procedures for M. bellii and will be a valuable resource for M. bellii and other threatened freshwater turtle conservation initiatives.
Collapse
|
3
|
Regeneration in Reptiles Generally and the New Zealand Tuatara in Particular as a Model to Analyse Organ Regrowth in Amniotes: A Review. J Dev Biol 2021; 9:jdb9030036. [PMID: 34564085 PMCID: PMC8482124 DOI: 10.3390/jdb9030036] [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: 06/03/2021] [Revised: 08/26/2021] [Accepted: 08/27/2021] [Indexed: 01/18/2023] Open
Abstract
The ability to repair injuries among reptiles, i.e., ectothermic amniotes, is similar to that of mammals with some noteworthy exceptions. While large wounds in turtles and crocodilians are repaired through scarring, the reparative capacity involving the tail derives from a combined process of wound healing and somatic growth, the latter being continuous in reptiles. When the tail is injured in juvenile crocodilians, turtles and tortoises as well as the tuatara (Rhynchocephalia: Sphenodon punctatus, Gray 1842), the wound is repaired in these reptiles and some muscle and connective tissue and large amounts of cartilage are regenerated during normal growth. This process, here indicated as “regengrow”, can take years to produce tails with similar lengths of the originals and results in only apparently regenerated replacements. These new tails contain a cartilaginous axis and very small (turtle and crocodilians) to substantial (e.g., in tuatara) muscle mass, while most of the tail is formed by an irregular dense connective tissue containing numerous fat cells and sparse nerves. Tail regengrow in the tuatara is a long process that initially resembles that of lizards (the latter being part of the sister group Squamata within the Lepidosauria) with the formation of an axial ependymal tube isolated within a cartilaginous cylinder and surrounded by an irregular fat-rich connective tissue, some muscle bundles, and neogenic scales. Cell proliferation is active in the apical regenerative blastema, but much reduced cell proliferation continues in older regenerated tails, where it occurs mostly in the axial cartilage and scale epidermis of the new tail, but less commonly in the regenerated spinal cord, muscles, and connective tissues. The higher tissue regeneration of Sphenodon and other lepidosaurians provides useful information for attempts to improve organ regeneration in endothermic amniotes.
Collapse
|
4
|
Souchet J, Bossu C, Darnet E, Le Chevalier H, Poignet M, Trochet A, Bertrand R, Calvez O, Martinez-Silvestre A, Mossoll-Torres M, Guillaume O, Clobert J, Barthe L, Pottier G, Philippe H, Gangloff EJ, Aubret F. High temperatures limit developmental resilience to high-elevation hypoxia in the snake Natrix maura (Squamata: Colubridae). Biol J Linn Soc Lond 2020. [DOI: 10.1093/biolinnean/blaa182] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Abstract
Climate change is generating range shifts in many organisms, notably along the altitudinal gradient. However, moving up in altitude exposes organisms to lower oxygen availability, which may negatively affect development and fitness, especially at high temperatures. To test this possibility in a potentially upward-colonizing species, we artificially incubated developing embryos of the viperine snake Natrix maura Linnaeus 1758, using a split-clutch design, in conditions of extreme high elevation or low elevation at two ecologically-relevant incubation temperatures (24 and 32 °C). Embryos at low and extreme high elevations incubated at cool temperatures did not differ in development time, hatchling phenotype or locomotor performance. However, at the warmer incubation temperature and at extreme high elevation, hatching success was reduced. Further, embryonic heart rates were lower, incubation duration longer and juveniles born smaller. Nonetheless, snakes in this treatment were faster swimmers than siblings in other treatment groups, suggesting a developmental trade-off between size and performance. Constraints on development may be offset by the maintenance of important performance metrics, thus suggesting that early life-history stages will not prevent the successful colonization of high-elevation habitat even under the dual limitations of reduced oxygen and increased temperature.
Collapse
Affiliation(s)
- Jérémie Souchet
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Coralie Bossu
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Elodie Darnet
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Hugo Le Chevalier
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Manon Poignet
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Audrey Trochet
- Société Herpétologique de France, Muséum National d’Histoire Naturelle, CP41, 57 rue Cuvier, Paris, France
| | - Romain Bertrand
- Laboratoire Évolution et Diversité Biologique, UMR 5174 Université de Toulouse III Paul Sabatier, CNRS, IRD, Toulouse, France
| | - Olivier Calvez
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | | | - Marc Mossoll-Torres
- Bomosa, Pl. Parc de la Mola, 10 Torre Caldea 7º, Les Escaldes, Andorra
- Pirenalia, c/ de la rectoria, 2 Casa Cintet, Encamp, Andorra
| | - Olivier Guillaume
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Jean Clobert
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
| | - Laurent Barthe
- Société Herpétologique de France, Muséum National d’Histoire Naturelle, CP41, 57 rue Cuvier, Paris, France
- Nature En Occitanie, 14 rue de Tivoli, Toulouse, France
| | | | - Hervé Philippe
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
- Département de Biochimie, Centre Robert-Cedergren, Université de Montréal, Montréal, QC, Canada
| | - Eric J Gangloff
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
- Department of Zoology, Ohio Wesleyan University, 61 Sandusky Street, Delaware, Ohio, USA
| | - Fabien Aubret
- Station d’Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, UMR 5321 CNRS—Université Paul Sabatier, Moulis, France
- School of Molecular and Life Sciences, Curtin University, Brand Drive, Bentley, WA, Australia
| |
Collapse
|
5
|
Souchet J, Gangloff EJ, Micheli G, Bossu C, Trochet A, Bertrand R, Clobert J, Calvez O, Martinez-Silvestre A, Darnet E, LE Chevalier H, Guillaume O, Mossoll-Torres M, Barthe L, Pottier G, Philippe H, Aubret F. High-elevation hypoxia impacts perinatal physiology and performance in a potential montane colonizer. Integr Zool 2020; 15:544-557. [PMID: 32649806 PMCID: PMC7689776 DOI: 10.1111/1749-4877.12468] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Climate change is generating range shifts in many organisms, notably along the elevational gradient in mountainous environments. However, moving up in elevation exposes organisms to lower oxygen availability, which may reduce the successful reproduction and development of oviparous organisms. To test this possibility in an upward‐colonizing species, we artificially incubated developing embryos of the viperine snake (Natrix maura) using a split‐clutch design, in conditions of extreme high elevation (hypoxia at 2877 m above sea level; 72% sea‐level equivalent O2 availability) or low elevation (control group; i.e. normoxia at 436 m above sea level). Hatching success did not differ between the two treatments. Embryos developing at extreme high elevation had higher heart rates and hatched earlier, resulting in hatchlings that were smaller in body size and slower swimmers compared to their siblings incubated at lower elevation. Furthermore, post‐hatching reciprocal transplant of juveniles showed that snakes which developed at extreme high elevation, when transferred back to low elevation, did not recover full performance compared to their siblings from the low elevation incubation treatment. These results suggest that incubation at extreme high elevation, including the effects of hypoxia, will not prevent oviparous ectotherms from producing viable young, but may pose significant physiological challenges on developing offspring in ovo. These early‐life performance limitations imposed by extreme high elevation could have negative consequences on adult phenotypes, including on fitness‐related traits.
Collapse
Affiliation(s)
- Jérémie Souchet
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Eric J Gangloff
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France.,Department of Zoology, Ohio Wesleyan University, Delaware, Ohio, USA
| | - Gaëlle Micheli
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Coralie Bossu
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Audrey Trochet
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Romain Bertrand
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Jean Clobert
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Olivier Calvez
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | | | - Elodie Darnet
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Hugo LE Chevalier
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Olivier Guillaume
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| | - Marc Mossoll-Torres
- Bomosa, Pl. Parc de la Mola, Les Escaldes, Andorra.,Pirenalia, Encamp, Andorra
| | | | | | - Hervé Philippe
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France.,Département de Biochimie, Centre Robert-Cedergren, Université de Montréal, Montréal, Canada
| | - Fabien Aubret
- Station d'Ecologie Théorique et Expérimentale du Centre National de la Recherche Scientifique, Moulis, France
| |
Collapse
|
6
|
Jarvie S, Jowett T, Thompson MB, Seddon PJ, Cree A. Effects of Warm Temperatures on Metabolic Rate and Evaporative Water Loss in Tuatara, a Cool-Climate Rhynchocephalian Survivor. Physiol Biochem Zool 2018; 91:950-966. [PMID: 29863954 DOI: 10.1086/698495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The thermal sensitivity of physiological rates is a key characteristic of organisms. For tuatara (Sphenodon punctatus), the last surviving member of the reptilian order Rhynchocephalia and an unusually cold-tolerant reptile, we aimed to clarify responses in indices of metabolic rate (oxygen consumption [[Formula: see text]] and carbon dioxide production [[Formula: see text]]) as well as rates of total evaporative water loss (TEWL) to temperatures at the warmer end of the known tolerated range; currently, patterns for metabolic rate are unclear above 25°C, and TEWL has not been measured above 25°C. We first established that metabolic rate was lowest during the photophase and then measured [Formula: see text], [Formula: see text], and TEWL at six temperatures (12°, 20°, 24°, 27°, 29°, and 30°C) during this phase. Consistent with our predictions, we found that mass-adjusted [Formula: see text], [Formula: see text], and TEWL increased at least 3.5-fold between 12° and 30°C (at 30°C, rates were 2.509 mL g-1 h-1, 2.001 mL g-1 h-1, and 1.829 mg-1 g-1 h-1, respectively). Temperature coefficients (Q10 values) for mass-adjusted [Formula: see text] and TEWL showed thermal dependence between 12° and 29°C but with a reduced increase or thermal independence between 29° and 30°C. There was no observed effect of egg incubation temperature (inferred sex) on the subsequent metabolic rates of juveniles. The respiratory exchange ratio implied a switch from carbohydrate metabolism at <22°C to lipid metabolism at >27°C. The rigorous measurement of [Formula: see text] and TEWL provides a basis for future studies to predict the thermal sensitivity of tuatara to human-mediated climate change.
Collapse
|
7
|
Hansson A, Olsson M. The Influence of Incubation Temperature on Phenotype of Australian Painted Dragons (Ctenophorus pictus). HERPETOLOGICA 2018. [DOI: 10.1655/herpetologica-d-17-00052.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Alexander Hansson
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18, SE 413 90 Gothenburg, Sweden
| | - Mats Olsson
- Department of Biological and Environmental Sciences, University of Gothenburg, Medicinaregatan 18, SE 413 90 Gothenburg, Sweden
| |
Collapse
|
8
|
While GM, Noble DW, Uller T, Warner DA, Riley JL, Du W, Schwanz LE. Patterns of developmental plasticity in response to incubation temperature in reptiles. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:162-176. [DOI: 10.1002/jez.2181] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/16/2018] [Accepted: 05/07/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Geoffrey M. While
- School of Biological Sciences University of Tasmania Hobart Australia
| | - Daniel W.A. Noble
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences University of New South Wales Sydney Australia
| | - Tobias Uller
- Department of Biology Lund University Lund Sweden
| | - Daniel A. Warner
- Department of Biological Sciences Auburn University Auburn Alabama
| | - Julia L. Riley
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences University of New South Wales Sydney Australia
- Department of Biological Sciences Macquarie University Sydney Australia
| | - Wei‐Guo Du
- Institute of Zoology Chinese Academy of Sciences Beijing China
| | - Lisa E. Schwanz
- Evolution & Ecology Research Centre School of Biological, Earth, and Environmental Sciences University of New South Wales Sydney Australia
| |
Collapse
|
9
|
Nelson NJ, Keall SN, Hare KM. Temperature selection by juvenile tuatara (Sphenodon punctatus) is not influenced by temperatures experienced as embryos. J Therm Biol 2017; 69:261-266. [PMID: 29037392 DOI: 10.1016/j.jtherbio.2017.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Revised: 08/14/2017] [Accepted: 08/14/2017] [Indexed: 11/19/2022]
Abstract
Most reptiles thermoregulate to achieve body temperatures needed for biological processes, such as digestion and growth. Temperatures experienced during embryogenesis may also influence post-hatching growth rate, potentially through influencing post-hatching choice of temperatures. We investigated in laboratory settings whether embryonic temperatures (constant 18°C, 21°C and 22°C) influence selected body temperatures (Tsel) of juvenile tuatara (Sphenodon punctatus), providing a possible mechanism for differences in growth rates. We found that incubation temperature does not influence Tsel. Although the average daily mean Tsel was 21.6 ± 0.3°C, we recorded individual Tsel values up to 33.5°C in juvenile tuatara, which is higher than expected and above the panting threshold of 31-33°C reported for adults. We found diel patterns of Tsel of juvenile tuatara, observing a general pattern of two apparent peaks and troughs per day, with Tsel being significantly lower around dawn and at 1500h than any other time. When comparing our results with other studies on tuatara there is a remarkable consistency in mean Tsel of ~ 21°C across tuatara of different ages, sizes and acclimatization histories. The ability of juvenile tuatara to withstand a wide range of temperatures supports their former widespread distribution throughout New Zealand and warrants further investigation into their plasticity to withstand climate warming, particularly where they have choices of habitat and the ability to thermoregulate.
Collapse
Affiliation(s)
- Nicola J Nelson
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand.
| | - Susan N Keall
- School of Biological Sciences, Victoria University of Wellington, PO Box 600, Wellington 6140, New Zealand
| | - Kelly M Hare
- Research Office, The Open Polytechnic of New Zealand, Private Bag 31914, Lower Hutt 5040, New Zealand
| |
Collapse
|
10
|
Noble DWA, Stenhouse V, Schwanz LE. Developmental temperatures and phenotypic plasticity in reptiles: a systematic review and meta-analysis. Biol Rev Camb Philos Soc 2017; 93:72-97. [DOI: 10.1111/brv.12333] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 03/14/2017] [Accepted: 03/17/2017] [Indexed: 12/15/2022]
Affiliation(s)
- Daniel W. A. Noble
- School of Biological, Earth and Environmental Sciences, Ecology and Evolution Research Centre; The University of New South Wales, Sydney, 2052; Australia
| | - Vaughn Stenhouse
- School of Biological Sciences; Victoria University; Wellington 6037 New Zealand
| | - Lisa E. Schwanz
- School of Biological, Earth and Environmental Sciences, Ecology and Evolution Research Centre; The University of New South Wales, Sydney, 2052; Australia
| |
Collapse
|
11
|
McGlashan JK, Thompson MB, Van Dyke JU, Spencer RJ. Thyroid Hormones Reduce Incubation Period without Developmental or Metabolic Costs in Murray River Short-Necked Turtles (Emydura macquarii). Physiol Biochem Zool 2017; 90:34-46. [DOI: 10.1086/689744] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
12
|
Yu Y, Li Z, Pan J. Changes in pigment, spectral transmission and element content of pink chicken eggshells with different pigment intensity during incubation. PeerJ 2016; 4:e1825. [PMID: 27019785 PMCID: PMC4806607 DOI: 10.7717/peerj.1825] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 02/27/2016] [Indexed: 11/22/2022] Open
Abstract
Objective. The objective of this study was to investigate changes in pigment, spectral transmission and element content of chicken eggshells with different intensities of pink pigment during the incubation period. We also investigated the effects of the region (small pole, equator and large pole) and pink pigment intensity of the chicken eggshell on the percent transmission of light passing through the chicken eggshells. Method. Eggs of comparable weight from a meat-type breeder (Meihuang) were used, and divided based on three levels of pink pigment (light, medium and dark) in the eggshells. During the incubation (0–21 d), the values of the eggshell pigment (ΔE, L∗, a∗, b∗) were measured. The percent transmission of light for different regions and intensities of eggshell pigmentation was measured by using the visible wavelength range of 380–780 nm. Result. Three measured indicators of eggshell color, ΔE, L∗ and a∗, did not change significantly during incubation. Compared with other regions and pigment intensities, eggshell at the small pole and with light pigmentation intensity showed the highest percent transmission of light. The transmission value varied significantly (P < 0.001) with incubation time. The element analysis of eggshells with different levels of pink pigment showed that the potassium content of the eggshells for all pigment levels decreased significantly during incubation. Conclusion. In summary, pigment intensity and the region of the eggshell influenced the percent transmission of light of eggshell. Differences in the spectral characteristics of different eggshells may influence the effects of photostimulation during the incubation of eggs. All of these results will be applicable for perfecting the design of light intensity for lighted incubation to improve productivity.
Collapse
Affiliation(s)
- Yue Yu
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, China; State Key Laboratory of Soil Plant Machinery System Technology, Beijing, China
| | - Zhanming Li
- Department of Biosystems Engineering, Zhejiang University , Hangzhou , China
| | - Jinming Pan
- Department of Biosystems Engineering, Zhejiang University, Hangzhou, China; State Key Laboratory of Soil Plant Machinery System Technology, Beijing, China
| |
Collapse
|
13
|
Mello RSR, Besson AA, Hare KM, Fay V, Smith E, Cree A. Adjustment of juvenile tuatara to a cooler, southern climate: operative temperatures, emergence behaviour and growth rate. NEW ZEALAND JOURNAL OF ZOOLOGY 2013. [DOI: 10.1080/03014223.2013.775167] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- RSR Mello
- Department of Zoology, University of Otago, Dunedin, New Zealand
- Current address: HRT Oil & Gas, Manaus, Brazil
| | - AA Besson
- Department of Zoology, University of Otago, Dunedin, New Zealand
| | - KM Hare
- Department of Zoology, University of Otago, Dunedin, New Zealand
- Current address: Research Office, Victoria University of Wellington, Wellington, New Zealand
| | - V Fay
- Orokonui Ecosanctuary, Dunedin, New Zealand
| | - E Smith
- Orokonui Ecosanctuary, Dunedin, New Zealand
| | - A Cree
- Department of Zoology, University of Otago, Dunedin, New Zealand
| |
Collapse
|
14
|
Clarke DN, Zani PA. Effects of night-time warming on temperate ectotherm reproduction: potential fitness benefits of climate change for side-blotched lizards. ACTA ACUST UNITED AC 2012; 215:1117-27. [PMID: 22399656 DOI: 10.1242/jeb065359] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Temperate ectotherms, especially those at higher latitudes, are expected to benefit from climate warming, but few data yet exist to verify this prediction. Furthermore, most previous studies on the effects of climate change utilized a model of uniform annual change, which assumes that temperature increases are symmetric on diurnal or seasonal time scales. In this study, we simulated observed trends in the asymmetric alteration of diurnal temperature range by increasing night-time temperatures experienced by female lizards during their ovarian cycle as well as by the resulting eggs during their incubation. We found that higher night-time temperatures during the ovarian cycle increased the probability of reproductive success and decreased the duration of the reproductive cycle, but did not affect embryo stage or size at oviposition, clutch size, egg mass or relative clutch mass. Furthermore, higher incubation temperatures increased hatchling size and decreased incubation period but had no effect on incubation success. Subsequent hatchlings were more likely to survive winter if they hatched earlier, though our sample size of hatchlings was relatively small. These findings indicate that higher night-time temperatures mainly affect rate processes and that certain aspects of life history are less directly temperature dependent. As our findings confirm that climate warming is likely to increase the rate of development as well as advance reproductive phenology, we predict that warmer nights during the breeding season will increase reproductive output as well as subsequent survival in many temperate ectotherms, both of which should have positive fitness effects.
Collapse
Affiliation(s)
- Donald N Clarke
- Department of Biology, Whitman College, Walla Walla, WA 99362, USA
| | | |
Collapse
|
15
|
Mitchell NJ, Jones TV, Kuchling G. Simulated climate change increases juvenile growth in a Critically Endangered tortoise. ENDANGER SPECIES RES 2012. [DOI: 10.3354/esr00410] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
16
|
Gartrell BD, Jillings E, Adlington BA, Mack H, Nelson NJ. Health screening for a translocation of captive-reared tuatara (Sphenodon punctatus) to an island refuge. N Z Vet J 2011; 54:344-9. [PMID: 17151736 DOI: 10.1080/00480169.2006.36722] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
AIMS To screen tuatara undergoing translocation from a captive crèche to an island refuge for evidence of health and known diseases, and apply basic epidemiological techniques to assess the significance of disease test results. METHODS Tuatara (n=353) were physically examined and samples were taken from a random selection (n=30) for estimated white cell counts, screening for haemoparasites, and culture for Salmonella, Yersinia, Aeromonas and Campylobacter spp. Direct faecal smears were carried out on-site, and faecal floats were later performed to assess levels of endoparasitism with helminths and protozoa (n=69). Modified Ziehl-Neelsen staining was used to screen faecal smears, and positive specimens were further screened using an immunofluorescence antibody (IFA) test for Cryptosporidium oocysts. RESULTS There was no evidence of external parasites on any of the animals examined and only one animal had a gross abnormality. All estimated white cell counts were in the range 2.8- 17.5 x 10(9)/L. No haemoparasites were observed. There were no enteric pathogens cultured, indicating the intestinal carriage of these bacteria in the tuatara was <9.4%. Of the 69 individual faecal samples examined, 12 (17%) had unidentified coccidial oocysts, 21 (30%) had nematode ova of various kinds, and 12 (17%) had intestinal carriage of motile protozoa consistent with Trichomonas spp and another unidentified organism. Nineteen (28%) tuatara had acid-fast oocysts present; however, IFA staining failed to detect any Cryptosporidium oocysts. CONCLUSIONS Our understanding of the diversity of gastrointestinal endoparasites affecting tuatara is inadequate as many of the parasite ova seen could not be identified. This is the first record of tuatara as a host for Trichomonas spp of protozoa in the gastrointestinal tract.
Collapse
Affiliation(s)
- B D Gartrell
- Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Private Bag 11222, Palmerston North, New Zealand.
| | | | | | | | | |
Collapse
|
17
|
Andrewartha SJ, Mitchell NJ, Frappell PB. Does incubation temperature fluctuation influence hatchling phenotypes in reptiles? A test using parthenogenetic geckos. Physiol Biochem Zool 2010; 83:597-607. [PMID: 20477533 DOI: 10.1086/652245] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Many lineages of parthenogenetic organisms have persisted through significant environmental change despite the constraints imposed by their fixed genotype and limited evolutionary potential. The ability of parthenogens to occur sympatrically with sexual relatives may in part be due to phenotypic plasticity in their responses to their environment, especially with respect to incubation temperature--a maternally selected trait. Here we measured the incubation temperatures selected by two lineages of triploid parthenogenic geckos in the Heteronotia binoei complex by allowing them to deposit clutches along a thermal gradient. The average nest temperature selected was 28.4 degrees C, with no significant differences between parthenogenic races or individual clones. To investigate the effect of nest-temperature variability on physiological and morphological traits, we incubated eggs from different races at one of four incubation regimes (32 degrees +/- 0 degrees, +/- 3 degrees , +/- 5 degrees , or +/- 9 degrees C). Embryos incubated at constant 32 degrees C developed faster than embryos reared under increasing extremes of diel temperature fluctuation (+/- 3 degrees , +/- 5 degrees C), and incubation at 32 degrees +/- 9 degrees C was unsuccessful. Incubation regime had no effect on the body size, preferred substrate temperature, or mass-specific .V(O2) of hatchlings. However, parthenogenic race had a significant effect on egg mass, tail length, snout-to-vent length, total length, and .V(O2) . We conclude that developmental traits are strongly influenced by clonal genotypes in this parthenogenic complex but are well buffered against fluctuations in incubation temperature.
Collapse
Affiliation(s)
- Sarah J Andrewartha
- Adaptational and Respiratory Physiology Laboratory, Department of Zoology, La Trobe University, Melbourne, Victoria 3086, Australia
| | | | | |
Collapse
|
18
|
Schwanz LE, Spencer RJ, Bowden RM, Janzen FJ. Climate and predation dominate juvenile and adult recruitment in a turtle with temperature‐dependent sex determination. Ecology 2010; 91:3016-26. [DOI: 10.1890/09-1149.1] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Lisa E. Schwanz
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
| | - Ricky-John Spencer
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
| | - Rachel M. Bowden
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa 50011 USA
| |
Collapse
|
19
|
Jones MEH, Lappin AK. Bite‐force performance of the last rhynchocephalian (Lepidosauria:Sphenodon). J R Soc N Z 2009. [DOI: 10.1080/03014220909510565] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
20
|
Mitchell NJ, Kearney MR, Nelson NJ, Porter WP. Predicting the fate of a living fossil: how will global warming affect sex determination and hatching phenology in tuatara? Proc Biol Sci 2008; 275:2185-93. [PMID: 18595840 DOI: 10.1098/rspb.2008.0438] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
How will climate change affect species' reproduction and subsequent survival? In many egg-laying reptiles, the sex of offspring is determined by the temperature experienced during a critical period of embryonic development (temperature-dependent sex determination, TSD). Increasing air temperatures are likely to skew offspring sex ratios in the absence of evolutionary or plastic adaptation, hence we urgently require means for predicting the future distributions of species with TSD. Here we develop a mechanistic model that demonstrates how climate, soil and topography interact with physiology and nesting behaviour to determine sex ratios of tuatara, cold-climate reptiles from New Zealand with an unusual developmental biology. Under extreme regional climate change, all-male clutches would hatch at 100% of current nest sites of the rarest species, Sphenodon guntheri, by the mid-2080s. We show that tuatara could behaviourally compensate for the male-biasing effects of warmer air temperatures by nesting later in the season or selecting shaded nest sites. Later nesting is, however, an unlikely response to global warming, as many oviparous species are nesting earlier as the climate warms. Our approach allows the assessment of the thermal suitability of current reserves and future translocation sites for tuatara, and can be readily modified to predict climatic impacts on any species with TSD.
Collapse
Affiliation(s)
- Nicola J Mitchell
- Centre for Evolutionary Biology, University of Western Australia, Crawley, WA 6009, Victoria University of Wellington, Wellington 6140, New Zealand.
| | | | | | | |
Collapse
|
21
|
SELIGMANN HERVÉ, MORAVEC JIŘÍ, WERNER YEHUDAHL. Morphological, functional and evolutionary aspects of tail autotomy and regeneration in the ‘living fossil’Sphenodon (Reptilia: Rhynchocephalia). Biol J Linn Soc Lond 2008. [DOI: 10.1111/j.1095-8312.2008.00975.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
22
|
Hare KM, Pledger S, Daugherty CH. Low Incubation Temperatures Negatively Influence Locomotor Performance and Behavior of the Nocturnal Lizard Oligosoma Suteri (Lacertidae: Scincidae). COPEIA 2008. [DOI: 10.1643/cp-06-275] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
23
|
Terezow MG, Nelson NJ, Markwell TJ. Circadian emergence and movement of captive juvenile tuatara (Sphenodonspp.). NEW ZEALAND JOURNAL OF ZOOLOGY 2008. [DOI: 10.1080/03014220809510116] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
24
|
Microsatellite DNA loci identify individuals and provide no evidence for multiple paternity in wild tuatara (Sphenodon: Reptilia). CONSERV GENET 2007. [DOI: 10.1007/s10592-007-9445-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
25
|
Hoare JM, Pledger S, Keall SN, Nelson NJ, Mitchell NJ, Daugherty CH. Conservation implications of a long-term decline in body condition of the Brothers Island tuatara (Sphenodon guntheri). Anim Conserv 2006. [DOI: 10.1111/j.1469-1795.2006.00061.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
26
|
|
27
|
Mitchell NJ, Nelson NJ, Cree A, Pledger S, Keall SN, Daugherty CH. Support for a rare pattern of temperature-dependent sex determination in archaic reptiles: evidence from two species of tuatara (Sphenodon). Front Zool 2006; 3:9. [PMID: 16808840 PMCID: PMC1559618 DOI: 10.1186/1742-9994-3-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2006] [Accepted: 06/29/2006] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The sex of many reptiles is determined by the temperature an embryo experiences during its development. Three patterns of temperature-dependent sex determination (TSD) have been defined, but one pattern where only males are produced above an upper temperature threshold (Type IB) is controversial. Here we report new data on the relationship between constant temperature incubation and sexual phenotype in two species of tuatara (Sphenodon), archaic reptiles of enormous zoological significance as the sole representatives of a once widespread reptilian order. RESULTS In both species, the pattern observed with constant incubation temperatures from 18 to 23 degrees C (or 24 degrees C) supported a female-->male (FM or Type IB) pattern of TSD: in Sphenodon guntheri males were produced above a pivotal temperature of 21.6 degrees C, and in S. punctatus (unnamed subspecies on Stephens Island, Cook Strait), males were produced above a pivotal temperature of 22.0 degrees C. The pivotal temperatures and scaling parameters differed between species (p < 0.001). The thermosensitive period (TSP), where temperature influences gonad morphogenesis, occurs between 0.25 and 0.55 of embryonic development. While it is possible that the more common female-->male-->female (FMF or Type II) pattern exists, with a second pivotal temperature above 23-24 degrees C, we review several lines of evidence to the contrary. Most notably, we show that in S. punctatus, the warmest natural nests during the TSP produce predominantly males. CONCLUSION An FM pattern of TSD could be currently adaptive in promoting sexual size dimorphism in tuatara. However, an FM pattern has particularly serious consequences for S. guntheri because current patterns of global warming could exacerbate the male bias already present in the relic population.
Collapse
Affiliation(s)
- Nicola J Mitchell
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
- School of Animal Biology, The University of Western Australia, Crawley 6009, Western Australia, Australia
| | - Nicola J Nelson
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Alison Cree
- Department of Zoology, University of Otago, Box 56, Dunedin, New Zealand
| | - Shirley Pledger
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Susan N Keall
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| | - Charles H Daugherty
- School of Biological Sciences, Victoria University of Wellington, P.O. Box 600, Wellington, New Zealand
| |
Collapse
|
28
|
Booth DT. Influence of Incubation Temperature on Hatchling Phenotype in Reptiles. Physiol Biochem Zool 2006; 79:274-81. [PMID: 16555187 DOI: 10.1086/499988] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2005] [Indexed: 11/03/2022]
Abstract
Incubation temperature influences hatchling phenotypes such as sex, size, shape, color, behavior, and locomotor performance in many reptiles, and there is growing concern that global warming might adversely affect reptile populations by altering frequencies of hatchling phenotypes. Here I overview a recent theoretical model used to predict hatchling sex of reptiles with temperature-dependent sex determination. This model predicts that sex ratios will be fairly robust to moderate global warming as long as eggs experience substantial daily cyclic fluctuations in incubation temperatures so that embryos are exposed to temperatures that inhibit embryonic development for part of the day. I also review studies that examine the influence of incubation temperature on posthatch locomotion performance and growth because these are the traits that are likely to have the greatest effect on hatchling fitness. The majority of these studies used artificial constant-temperature incubation, but some have addressed fluctuating incubation temperature regimes. Although the number of studies is small, it appears that fluctuating temperatures may enhance hatchling locomotor performance. This finding should not be surprising, given that the majority of natural reptile nests are relatively shallow and therefore experience daily fluctuations in incubation temperature.
Collapse
Affiliation(s)
- David T Booth
- Physiological Ecology Group, School of Integrative Biology, University of Queensland, Brisbane, Queensland 4072, Australia.
| |
Collapse
|
29
|
Birchard GF, Nelson NJ, Daugherty CH. A circadian rhythm in oxygen consumption rate in juvenile tuatara(Sphenodon punctatus). NEW ZEALAND JOURNAL OF ZOOLOGY 2006. [DOI: 10.1080/03014223.2006.9518443] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
30
|
Nelson NJ, Thompson MB, Pledger S, Keall SN, Daugherty CH. Induction of oviposition produces smaller eggs in tuatara(Sphenodon punctatus). NEW ZEALAND JOURNAL OF ZOOLOGY 2004. [DOI: 10.1080/03014223.2004.9518381] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|