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Wang Y, Hong X, Liu X, Li W, Chen C, Zhu J, Wei C, Zhu X, Yu L. Reproductive Output Reveals the Maternal Effects on Offspring Size-Number Trade-Off in Cultured Asian Yellow Pond Turtle ( Mauremys mutica). Animals (Basel) 2023; 13:2219. [PMID: 37444017 DOI: 10.3390/ani13132219] [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: 05/24/2023] [Revised: 06/30/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Offspring size-number trade-off is a critical component of life-history theory and is important for further understanding the reproductive strategies of animals. The relationship between this trade-off and maternal size has been explored in several turtle species, except for the Asian yellow pond turtle, Mauremys mutica. To investigate how the maternal condition affects offspring size and number, we explored the relationships among the maternal body size and the number and size of cultured M. mutica hatchlings using a 4-year dataset. Our results showed that different females not only produced different sizes of offspring but also produced different numbers of offspring. No trade-off in egg size number was detected. According to regression analysis, we did not find that the maternal body size significantly influenced the offspring mass; however, we detected that the offspring size was significantly correlated with the clutch size and maternal age. The mean body mass of offspring increased with maternal age, and the clutch size varied significantly over four years, which was correlated with offspring size, maternal body size and age. However, the number of offspring per female increased with the maternal plastron length rather than age. Our results were inconsistent with the optimal offspring size theory in that females did not increase their offspring size but rather increased the offspring number to increase their fitness, which will also provide a basis for the efficient cultivation management of turtles.
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Affiliation(s)
- Yakun Wang
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Xiaoyou Hong
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Xiaoli Liu
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Wei Li
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Chen Chen
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Junxian Zhu
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Chengqing Wei
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Xinping Zhu
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
| | - Lingyun Yu
- Key Laboratory of Tropical & Subtropical Fishery Resource Application & Cultivation of Ministry of Agriculture and Rural Affairs, Pearl River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Guangzhou 510380, China
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2
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Donini J, Selman W. Clutch Size, Clutch Frequency, and Egg Characteristics of Diamond-Backed Terrapins (Malaclemys terrapin) in Southwestern Louisiana. SOUTHEAST NAT 2022. [DOI: 10.1656/058.021.0307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jordan Donini
- Department of Pure and Applied Sciences, Florida Southwestern State College, 7505 Grand Lely Drive, Naples, FL 34113
| | - Will Selman
- Department of Biology, Millsaps College, Jackson, MS 39210
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3
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Thiem LR, Gienger CM. Hold on for one more day: Energetic costs of oviductal egg retention in Eastern Musk Turtles (Sternotherus odoratus). Physiol Biochem Zool 2022; 95:279-287. [DOI: 10.1086/720159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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4
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Jorgewich-Cohen G, Henrique RS, Dias PH, Sánchez-Villagra MR. The evolution of reproductive strategies in turtles. PeerJ 2022; 10:e13014. [PMID: 35295558 PMCID: PMC8919852 DOI: 10.7717/peerj.13014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 02/06/2022] [Indexed: 01/11/2023] Open
Abstract
Optimal egg size theory assumes that changes in the egg and clutch are driven by selection, resulting in adjustments for the largest possible production of offspring with the highest fitness. Evidence supports the idea that large-bodied turtles tend to produce larger clutches with small and round eggs, while smaller species produce small clutches with large and elongated eggs. Our goals were to investigate whether egg and clutch size follow the predictions of egg size theory, if there are convergent reproductive strategies, and identify ecological factors that influence clutch and egg traits across all clades of living turtles. Using phylogenetic methods, we tested the covariance among reproductive traits, if they are convergent among different turtle lineages, and which ecological factors influence these traits. We found that both egg shape and size inversely correlate with clutch size, although with different evolutionary rates, following the predictions of the egg size theory. We also present compelling evidence for convergence among different turtle clades, over at least two reproductive strategies. Furthermore, climatic zone is the only ecological predictor to influence both egg size and fecundity, while diet only influences egg size. We conclude that egg and clutch traits in Testudines evolved independently several times across non-directly related clades that converged to similar reproductive strategies. Egg and clutch characteristics follow the trade-offs predicted by egg size theory and are influenced by ecological factors. Climatic zone and diet play an important role in the distribution of reproductive characteristics among turtles.
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Affiliation(s)
| | - Rafael S. Henrique
- Laboratório de Anfíbios, Instituto de Biociências, Universidade de São Paulo, São Paulo, São Paulo, Brazil
| | - Pedro Henrique Dias
- Departamento de Zoologia, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
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5
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Heston L, Meylan P, Goessling JM. Life history consequences of miniaturization in turtles: evidence from the subfamily Kinosterninae (Testudines: Kinosternidae). Biol J Linn Soc Lond 2022. [DOI: 10.1093/biolinnean/blab163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
A miniaturized species is one that has endured ecological, physiological or life history costs due to small size and has implemented discrete strategies to compensate for those costs. We studied the impact of small size on the reproductive biology of the miniaturized turtle, Sternotherus minor (Kinosternidae: Kinosterninae), by exploring two alternative hypotheses that explain within-clutch trade-offs: the Optimal Egg Size Theory (OEST) and the Morphological Constraint Hypothesis (MCH). Female S. minor in this study showed a combination of reproductive parameters that support both the MCH and the OEST. Small individuals follow the MCH and larger individuals follow the OEST, fitting the previously proposed ‘threshold size-constrained’ model of egg size to female size. The large proportion of suboptimally-sized eggs (31.1%) produced in our study population is evidence that a novel strategy that compensates for very small size exists in this kinosternine turtle. Early reproduction in our study population, as well as a mobile plastron made up of a reduced number of bones and scutes in all members of this subfamily, is strong evidence of paedomorphosis, a frequent consequence of miniaturization. Re-examination of reproduction in other kinosternines will further test how this life history strategy facilitated miniaturization in testudines.
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Affiliation(s)
- Lark Heston
- Natural Sciences, Eckerd College, 4200 54th Avenue S, St. Petersburg, FL 33711, USA
| | - Peter Meylan
- Natural Sciences, Eckerd College, 4200 54th Avenue S, St. Petersburg, FL 33711, USA
| | - Jeffrey M Goessling
- Natural Sciences, Eckerd College, 4200 54th Avenue S, St. Petersburg, FL 33711, USA
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6
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Lindeman PV. Comparative Reproductive Allometry of Syntopic Black-Knobbed Sawbacks (Graptemys nigrinoda) and Alabama Map Turtles (Graptemys pulchra) in the Alabama River, with Comparison to Three Congeners. CHELONIAN CONSERVATION AND BIOLOGY 2020. [DOI: 10.2744/ccb-1399.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Peter V. Lindeman
- Department of Biology and Health Sciences, Edinboro University of Pennsylvania, 230 Scotland Road, Edinboro, Pennsylvania 16444 USA []
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7
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Thompson DM, Fillmore R, Fillmore BM, Graves KG, Ligon DB. Reproductive Investment Patterns in a Captive Population of Alligator Snapping Turtles (Macrochelys temminckii
). HERPETOLOGICA 2019. [DOI: 10.1655/herpetologica-d-19-00007.1] [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)
- Denise M. Thompson
- Department of Biology, Missouri State University, Springfield, MO 65897, USA
| | - Rebecca Fillmore
- Durant Hatchery, Oklahoma Department of Wildlife Conservation, Caddo, OK 74729, USA
| | - Brian M. Fillmore
- US Fish and Wildlife Service, Tishomingo National Fish Hatchery, Tishomingo, OK 73460, USA
| | - Kerry G. Graves
- US Fish and Wildlife Service, Tishomingo National Fish Hatchery, Tishomingo, OK 73460, USA
| | - Day B. Ligon
- Department of Biology, Missouri State University, Springfield, MO 65897, USA
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8
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Suriyamongkol T, Mali I. Aspects of the Reproductive Biology of the Rio Grande Cooter (Pseudemys gorzugi) on the Black River, New Mexico. CHELONIAN CONSERVATION AND BIOLOGY 2019. [DOI: 10.2744/ccb-1385.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Thanchira Suriyamongkol
- Department of Biology, Eastern New Mexico University, 1500 South Avenue K, Station 33, Portales, New Mexico 88130 USA [; ]
| | - Ivana Mali
- Department of Biology, Eastern New Mexico University, 1500 South Avenue K, Station 33, Portales, New Mexico 88130 USA [; ]
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9
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Iverson JB, Lindeman PV, Lovich JE. Understanding reproductive allometry in turtles: A slippery "slope". Ecol Evol 2019; 9:11891-11903. [PMID: 31695895 PMCID: PMC6822033 DOI: 10.1002/ece3.5697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 09/02/2019] [Accepted: 09/05/2019] [Indexed: 11/08/2022] Open
Abstract
Measures of reproductive output in turtles are generally positively correlated with female body size. However, a full understanding of reproductive allometry in turtles requires logarithmic transformation of reproductive and body size variables prior to regression analyses. This allows for slope comparisons with expected linear or cubic relationships for linear to linear and linear to volumetric variables, respectively. We compiled scaling data using this approach from published and unpublished turtle studies (46 populations of 25 species from eight families) to quantify patterns among taxa. Our results suggest that for log-log comparisons of clutch size, egg width, egg mass, clutch mass, and pelvic aperture width to shell length, all scale hypoallometrically despite theoretical predictions of isometry. Clutch size generally scaled at ~1.7 to 2.0 (compared to an isometric expectation of 3.0), egg width at ~0.5 (compared to an expectation of 1.0), egg mass at ~1.1 to 1.3 (3.0), clutch mass at ~2.5 to 2.8 (3.0), and pelvic aperture width at 0.8-0.9 (1.0). We also found preliminary evidence that scaling may differ across years and clutches even in the same population, as well as across populations of the same species. Future investigators should aspire to collect data on all these reproductive parameters and to report log-log allometric analyses to test our preliminary conclusions regarding reproductive allometry in turtles.
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Affiliation(s)
| | - Peter V. Lindeman
- Department of Biology and Health SciencesEdinboro University of PennsylvaniaEdinboroPAUSA
| | - Jeffrey E. Lovich
- U.S. Geological SurveySouthwest Biological Science CenterFlagstaffAZUSA
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10
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Averill-Murray RC, Christopher TE, Henen BT. Reproductive Ecology and Life History of Female Sonoran Desert Tortoises (Gopherus morafkai). HERPETOLOGICAL MONOGRAPHS 2018. [DOI: 10.1655/herpmonographs-d-18-00003.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Roy C. Averill-Murray
- Nongame Branch, Arizona Game and Fish Department, 5000 West Carefree Highway, Phoenix, AZ 85086, USA
| | - Terry E. Christopher
- Smithsonian Institution, Department of Zoological Research, National Zoological Park, 3001 Connecticut Avenue, Washington, DC 20008, USA
| | - Brian T. Henen
- Smithsonian Institution, Department of Zoological Research, National Zoological Park, 3001 Connecticut Avenue, Washington, DC 20008, USA
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11
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Hofmeyr MD, Henen BT, Loehr VJT. Reproductive investments of a small, arid zone tortoise
Chersobius signatus
: Follicle and egg development. ACTA ZOOL-STOCKHOLM 2018. [DOI: 10.1111/azo.12269] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Margaretha D. Hofmeyr
- Chelonian Biodiversity and Conservation Department of Biodiversity and Conservation Biology University of the Western Cape Bellville South Africa
| | - Brian T. Henen
- Chelonian Biodiversity and Conservation Department of Biodiversity and Conservation Biology University of the Western Cape Bellville South Africa
- Marine Air Ground Task Force Training Command, Environmental Affairs, MCAGCC Twentynine Palms California
| | - Victor J. T. Loehr
- Chelonian Biodiversity and Conservation Department of Biodiversity and Conservation Biology University of the Western Cape Bellville South Africa
- Homopus Research Foundation IJsselstein The Netherlands
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12
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Burke RL, Clendening B, Kanonik A. Long-term increases in clutch size in common snapping turtles ( Chelydra serpentina) and diamondback terrapins ( Malaclemys terrapin). J NAT HIST 2018. [DOI: 10.1080/00222933.2018.1483539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Russell L. Burke
- Department of Biology, Hofstra University, Hempstead, NY, USA
- American Littoral Society, Northeast Chapter, Broad Channel, NY, USA
| | | | - Alexandra Kanonik
- American Littoral Society, Northeast Chapter, Broad Channel, NY, USA
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13
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Attard MR, Sherratt E, McDonald P, Young I, Vidal-García M, Wroe S. A new, three-dimensional geometric morphometric approach to assess egg shape. PeerJ 2018; 6:e5052. [PMID: 29967731 PMCID: PMC6026453 DOI: 10.7717/peerj.5052] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/02/2018] [Indexed: 11/20/2022] Open
Abstract
This paper proposes a new methodology to quantify patterns of egg shape variation using geometric morphometrics of three-dimensional landmarks captured on digitally reconstructed eggshells and demonstrates its performance in capturing shape variation at multiple biological levels. This methodology offers unique benefits to complement established linear measurement or two-dimensional (2D) contour profiling techniques by (i) providing a more precise representation of eggshell curvature by accounting for variation across the entire surface of the egg; (ii) avoids the occurrence of correlations from combining multiple egg shape features; (iii) avoids error stemming from projecting a highly-curved three-dimensional (3D) object into 2D space; and (iv) enables integration into 3D workflows such as finite elements analysis. To demonstrate, we quantify patterns of egg shape variation and estimate morphological disparity at multiple biological levels, within and between clutches and among species of four passerine species of different lineages, using volumetric dataset obtained from micro computed tomography. The results indicate that species broadly have differently shaped eggs, but with extensive within-species variation so that all four-focal species occupy a range of shapes. Within-species variation is attributed to between-clutch differences in egg shape; within-clutch variation is surprisingly substantial. Recent comparative analyses that aim to explain shape variation among avian taxa have largely ignored potential biases due to within-species variation, or use methods limited to a narrow range of egg shapes. Through our approach, we suggest that there is appreciable variation in egg shape across clutches and that this variation needs to be accounted for in future research. The approach developed in this study to assess variation in shape is freely accessible and can be applied to any spherical-to-conical shaped object, including eggs of non-avian dinosaurs and reptiles through to other extant taxa such as poultry.
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Affiliation(s)
- Marie R.G. Attard
- Zoology Department, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, South Yorkshire, UK
| | - Emma Sherratt
- Zoology Department, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- Department of Ecology and Evolutionary Biology, School of Biological Sciences, The University of Adelaide, Adelaide, SA, Australia
| | - Paul McDonald
- Zoology Department, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
| | - Iain Young
- Zoology Department, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
- School of Life and Environmental Sciences, Faculty of Science, University of Sydney, Sydney, NSW, Australia
| | - Marta Vidal-García
- Ecology and Evolution, Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Stephen Wroe
- Zoology Department, School of Environmental and Rural Science, University of New England, Armidale, NSW, Australia
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14
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Deeming DC. Nesting environment may drive variation in eggshell structure and egg characteristics in the Testudinata. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:331-342. [DOI: 10.1002/jez.2169] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 03/28/2018] [Accepted: 04/21/2018] [Indexed: 11/11/2022]
Affiliation(s)
- D. Charles Deeming
- School of Life Sciences; Joseph Banks Laboratories; University of Lincoln; Lincoln, LN6 7DL UK
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15
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Cordero GA. Is the Pelvis Sexually Dimorphic in Turtles? Anat Rec (Hoboken) 2018; 301:1382-1389. [PMID: 29677702 DOI: 10.1002/ar.23831] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 12/27/2022]
Abstract
Variation in the pelvis is intrinsically linked to life history evolution. This is perhaps best exemplified by sexually dimorphic pelvic variation in bipedal primates. Yet, whether this trend is applicable to other taxa is unclear. Using turtle anatomy as a model, I tested the hypothesis that the pelvis is also sexually dimorphic in egg-laying tetrapods. I sampled a natural turtle population with female-biased sexual size dimorphism (i.e., larger females). I show that the area of the egg canal (pelvic aperture) is greater in females. Morphological differences between sexes were predicted by body size, such that skeletal shape deformation of the female ilium increased proportionally with pelvic aperture area. These results suggest that sexual pelvic dimorphism might be indirectly maintained by selection for large female size, consistent with the pelvic constraint hypothesis in reptiles. However, subsampling of similarly sized individuals revealed that pelvic aperture area and shape may vary in disproportion to body size. Comparisons of pelvic ontogenetic trajectories across multiple lineages are needed to clarify the occurrence of sexual pelvic dimorphism in turtles and other egg-laying tetrapods. My findings provide impetus to further explore how sex-specific functional demands influence the architecture of the pelvic girdle. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc.
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Affiliation(s)
- Gerardo A Cordero
- Department of Ecology, Evolution, and Organismal Biology, 251 Bessey Hall, Iowa State University, Ames, Iowa 5011
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16
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Escalona T, Adams DC, Valenzuela N. A lengthy solution to the optimal propagule size problem in the large-bodied South American freshwater turtle, Podocnemis unifilis. Evol Ecol 2017. [DOI: 10.1007/s10682-017-9922-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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17
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Berlant ZS, Stayton TC. Shell Morphology in the Kinosternidae: Functional and Evolutionary Patterns. HERPETOLOGICA 2017. [DOI: 10.1655/herpetologica-d-15-00064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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18
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Fehrenbach AK, Louque I, McFadden SL, Huntzinger C, Lyons E, Shively SH, Selman W, Lindeman PV. Habitat-Related Variation in Body Size and Reproductive Output and an Examination of Reproductive Allometry in the Sabine Map Turtle (Graptemys sabinensis) across Three River Drainages. COPEIA 2016. [DOI: 10.1643/ce-15-273] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Rasmussen ML, Litzgus JD. Patterns of maternal investment in spotted turtles (Clemmys guttata): Implications of trade-offs, scales of analyses, and incubation substrates. ECOSCIENCE 2015. [DOI: 10.2980/17-1-3298] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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20
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Kern MM, Guzy JC, Lovich JE, Gibbons JW, Dorcas ME. Relationships of maternal body size and morphology with egg and clutch size in the diamondback terrapin,Malaclemys terrapin(Testudines: Emydidae). Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12655] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Maximilian M. Kern
- Graduate Group in Ecology; University of California Davis; Davis CA 95616 USA
| | - Jacquelyn C. Guzy
- Department of Biological Sciences; University of Arkansas; Fayetteville AR 72701 USA
| | - Jeffrey E. Lovich
- U.S. Geological Survey; Southwest Biological Science Center; 2255 North Gemini Drive Flagstaff AZ 86001-1637 USA
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21
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Rollinson N, Rowe L. The positive correlation between maternal size and offspring size: fitting pieces of a life-history puzzle. Biol Rev Camb Philos Soc 2015; 91:1134-1148. [PMID: 26289842 DOI: 10.1111/brv.12214] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 07/03/2015] [Accepted: 07/23/2015] [Indexed: 11/27/2022]
Abstract
The evolution of investment per offspring (I) is often viewed through the lens of the classic theory, in which variation among individuals in a population is not expected. A substantial departure from this prediction arises in the form of correlations between maternal body size and I, which are observed within populations in virtually all taxonomic groups. Based on the generality of this observation, we suggest it is caused by a common underlying mechanism. We pursue a unifying explanation for this pattern by reviewing all theoretical models that attempt to explain it. We assess the generality of the mechanism upon which each model is based, and the extent to which data support its predictions. Two classes of adaptive models are identified: models that assume that the correlation arises from maternal influences on the relationship between I and offspring fitness [w(I)], and those that assume that maternal size influences the relationship between I and maternal fitness [W(I)]. The weight of evidence suggests that maternal influences on w(I) are probably not very general, and even for taxa where maternal influences on w(I) are likely, experiments fail to support model predictions. Models that assume that W(I) varies with maternal size appear to offer more generality, but the current challenge is to identify a specific and general mechanism upon which W(I) varies predictably with maternal size. Recent theory suggests the exciting possibility that a yet unknown mechanism modifies the offspring size-number trade-off function in a manner that is predictable with respect to maternal size, such that W(I) varies with size. We identify two promising avenues of inquiry. First, the trade-off might be modified by energetic costs that are associated with the initiation of reproduction ('overhead costs') and that scale with I, and future work could investigate what specific overhead costs are generally associated with reproduction and whether these costs scale with I. Second, the trade-off might be modified by virtue of condition-dependent offspring provisioning coupled with metabolic factors, and future work could investigate the proximate cause of, and generality of, condition-dependent offspring provisioning. Finally, drawing on the existing literature, we suggest that maternal size per se is not causatively related to variation in I, and the mechanism involved in the correlation is instead linked to maternal nutritional status or maternal condition, which is usually correlated with maternal size. Using manipulative experiments to elucidate why females with high nutritional status typically produce large offspring might help explain what specific mechanism underlies the maternal-size correlation.
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Affiliation(s)
- Njal Rollinson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, Ontario, M5S 3B2, Canada.
| | - Locke Rowe
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks St., Toronto, Ontario, M5S 3B2, Canada
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22
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Rothermel BB, Castellón TD. Factors Influencing Reproductive Output and Egg Size in a Southern Population of Gopher Tortoises. SOUTHEAST NAT 2014. [DOI: 10.1656/058.013.0403] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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23
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Oufiero CE, Gartner GEA. The effect of parity on morphological evolution among phrynosomatid lizards. J Evol Biol 2014; 27:2559-67. [PMID: 25263972 DOI: 10.1111/jeb.12485] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/15/2014] [Accepted: 08/17/2014] [Indexed: 11/29/2022]
Abstract
The shift from egg laying to live-bearing is one of the most well-studied transitions in evolutionary biology. Few studies, however, have assessed the effect of this transition on morphological evolution. Here, we evaluated the effect of reproductive mode on the morphological evolution of 10 traits, among 108 species of phrynosomatid lizards. We assess whether the requirement for passing shelled eggs through the pelvic girdle has led to morphological constraints in oviparous species and whether long gestation times in viviparous species have led to constraints in locomotor morphology. We fit models to the data that vary both in their tempo (strength and rate of selection) and mode of evolution (Brownian or Ornstein-Uhlenbeck) and estimates of trait optima. We found that most traits are best fit by a generalized multipeak OU model, suggesting differing trait optima for viviparous vs. oviparous species. Additionally, rates (σ(2) ) of both pelvic girdle and forelimb trait evolution varied with parity; viviparous species had higher rates. Hindlimb traits, however, exhibited no difference in σ(2) between parity modes. In a functional context, our results suggest that the passage of shelled eggs constrains the morphology of the pelvic girdle, but we found no evidence of morphological constraint of the locomotor apparatus in viviparous species. Our results are consistent with recent lineage diversification analyses, leading to the conclusion that transitions to viviparity increase both lineage and morphological diversification.
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Affiliation(s)
- C E Oufiero
- Department of Biological Sciences, Towson University, Towson, MD, USA
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Macip-Ríos R, Sustaita-Rodriguez VH, Casas-Andreu G. Evidence of Pelvic and Nonpelvic Constraint on Egg Size in Two Species ofKinosternonfrom Mexico. CHELONIAN CONSERVATION AND BIOLOGY 2013. [DOI: 10.2744/ccb-1038.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Allman PE, Place AR, Roosenburg WM. Geographic variation in egg size and lipid provisioning in the diamondback terrapin Malaclemys terrapin. Physiol Biochem Zool 2012; 85:442-9. [PMID: 22902372 DOI: 10.1086/667412] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Understanding phenotypic differentiation among populations of wide-ranging species remains at the core of life-history research, because adaptation to local environmental conditions is expected. For example, when energy resources influence offspring fitness (as in oviparous ectotherms), the egg and hatchling environments are expected to influence selection by acting on the amount of energy allocated to offspring. Here we identify population variation in egg mass, length, width, and volume from diamondback terrapin Malaclemys terrapin eggs collected in Rhode Island (RI), Maryland (MD), and South Carolina (SC). Egg size (mean volume: 7.6, 8.1, and 9.1 cc in RI, MD, and SC, respectively) and clutch size (mean no. eggs: 16.1, 12.2, and 6.0 in RI, MD, and SC, respectively) differed among populations, which indicated that females produce larger clutches with smaller eggs at high latitudes and smaller clutches of larger eggs at lower latitudes. Lipid analyses indicated that eggs from SC contained yolks with a higher proportion of nonpolar lipids than did eggs from MD or RI (mean percentage of nonpolar lipids: 22.3%, 22.5%, and 31.8% in RI, MD, and SC, respectively). Thus, female terrapins in SC are laying larger eggs with increased lipid content to provide more energy for the developing embryo. Interestingly, total triacylglycerol (energetic lipid) was greater in southern populations but occurred in higher proportions in northern populations (total triacylglycerol: 88.0%, 85.4%, and 81.9% in RI, MD, and SC, respectively). This variation in triacylglycerol levels demonstrates the necessity for quantifying each lipid component. These data indicate a difference in reproductive strategy by which females in northern populations invest in higher fecundity with less energetic resources per offspring, whereas females in southern populations invest in larger eggs with considerably greater energy reserves.
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Affiliation(s)
- Phil E Allman
- Ohio Center for Ecology and Evolutionary Studies, Department of Biological Sciences, Ohio University, Athens, OH 45710, USA.
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Lovich JE, Madrak SV, Drost CA, Monatesti AJ, Casper D, Znari M. Optimal egg size in a suboptimal environment: reproductive ecology of female Sonora mud turtles (Kinosternon sonoriense) in central Arizona, USA. AMPHIBIA-REPTILIA 2012. [DOI: 10.1163/156853812x634035] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We studied the reproductive ecology of female Sonora mud turtles (Kinosternon sonoriense) at Montezuma Well, a chemically-challenging natural wetland in central Arizona, USA. Females matured between 115.5 and 125 mm carapace length (CL) and 36-54% produced eggs each year. Eggs were detected in X-radiographs from 23 April-28 September (2007-2008) and the highest proportion (56%) of adult females with eggs occurred in June and July. Clutch frequency was rarely more than once per year. Clutch size was weakly correlated with body size, ranged from 1-8 (mean = 4.96) and did not differ significantly between years. X-ray egg width ranged from 17.8-21.7 mm (mean 19.4 mm) and varied more among clutches than within. Mean X-ray egg width of a clutch did not vary significantly with CL of females, although X-ray pelvic aperture width increased with CL. We observed no evidence of a morphological constraint on egg width. In addition, greater variation in clutch size, relative to egg width, suggests that egg size is optimized in this hydrologically stable but chemically-challenging habitat. We suggest that the diversity of architectures exhibited by the turtle pelvis, and their associated lack of correspondence to taxonomic or behavioral groupings, explains some of the variation observed in egg size of turtles.
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Affiliation(s)
- Jeffrey E. Lovich
- 1U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive, Flagstaff, Arizona 86001, USA
| | - Sheila V. Madrak
- 1U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive, Flagstaff, Arizona 86001, USA
- 2Present address: Department of Biology, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-4614, USA
| | - Charles A. Drost
- 1U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive, Flagstaff, Arizona 86001, USA
| | - Anthony J. Monatesti
- 1U.S. Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive, Flagstaff, Arizona 86001, USA
- 3Present address: National Park Service, Environmental Compliance, Lake Mead National Recreation Area, 601 Nevada Way, Boulder City, Nevada 89005, USA
| | - Dennis Casper
- 4National Park Service, Montezuma Castle National Monument, 527 South Main Street, Camp Verde, Arizona 86322, USA
| | - Mohammed Znari
- 5Laboratory “Biodiversity & Ecosystem Dynamics”, Department of Biology, Faculty of Science – Semlalia, Cadi Ayyad University, Avenue Prince Moulay Abdellah, P.O. Box 2390, 40000, Marrakech, Morocco
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Macip-Ríos R, Brauer-Robleda P, Casas-Andreu G, Arias-Cisneros MDL, Sustaita-Rodríguez VH. Evidence for the Morphological Constraint Hypothesis and Optimal Offspring Size Theory in the Mexican Mud Turtle (Kinosternon integrum). Zoolog Sci 2012; 29:60-5. [DOI: 10.2108/zsj.29.60] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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PRICE-REES SAMANTHAJ, CONGDON BRADLEYC, KROCKENBERGER ANDREWK. Size delays female senescence in a medium sized marsupial: The effects of maternal traits on annual fecundity in the northern brown bandicoot (Isoodon macrourus). AUSTRAL ECOL 2011. [DOI: 10.1111/j.1442-9993.2011.02279.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Loehr VJT, Henen BT, Hofmeyr MD. Reproductive Responses to Rainfall in the Namaqualand Speckled Tortoise. COPEIA 2011. [DOI: 10.1643/ce-09-072] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Bowden RM, Paitz RT, Janzen FJ. The Ontogeny of Postmaturation Resource Allocation in Turtles. Physiol Biochem Zool 2011; 84:204-11. [PMID: 21460531 DOI: 10.1086/658292] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- R M Bowden
- School of Biological Sciences, Illinois State University, Normal, IL, USA.
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Fischer B, Taborsky B, Kokko H. How to balance the offspring quality-quantity tradeoff when environmental cues are unreliable. OIKOS 2010. [DOI: 10.1111/j.1600-0706.2010.18642.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Bonnet X, Delmas V, El-Mouden H, Slimani T, Sterijovski B, Kuchling G. Is sexual body shape dimorphism consistent in aquatic and terrestrial chelonians? ZOOLOGY 2010; 113:213-20. [PMID: 20832271 DOI: 10.1016/j.zool.2010.03.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 02/18/2010] [Accepted: 03/15/2010] [Indexed: 11/27/2022]
Abstract
Comparisons between aquatic and terrestrial species provide an opportunity to examine how sex-specific adaptations interact with the environment to influence body shape. In terrestrial female tortoises, selection for fecundity favors the development of a large internal abdominal cavity to accommodate the clutch; in conspecific males, sexual selection favors mobility with large openings in the shell. To examine to what extent such trends apply in aquatic chelonians we compared the body shape of males and females of two aquatic turtles (Chelodina colliei and Mauremys leprosa). In both species, females were larger than males. When controlled for body size, females exhibited a greater relative internal volume and a higher body condition index than males; both traits potentially correlate positively with fecundity. Males were more streamlined (hydrodynamic), and exhibited larger openings in the shell providing more space to move their longer limbs; such traits probably improve mobility and copulation ability (the males chase and grab the female for copulation). Overall, although the specific constraints imposed by terrestrial and aquatic locomotion shape the morphology of chelonians differently (aquatic turtles were flatter, hence more hydrodynamic than terrestrial tortoises), the direction for sexual shape dimorphism remained unaffected. Our main conclusion is that the direction of sexual shape dimorphism is probably more consistent than sexual size dimorphism in the animal kingdom.
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Affiliation(s)
- Xavier Bonnet
- Centre d'Etudes Biologiques de Chizé, Centre National de la Recherche Scientifique, UPR 1934, F-79360 Beauvoir sur Niort, France.
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Rius M, Turon X, Dias GM, Marshall DJ. Propagule size effects across multiple life-history stages in a marine invertebrate. Funct Ecol 2009. [DOI: 10.1111/j.1365-2435.2009.01668.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Ruane S, Dinkelacker SA, Iverson JB. Demographic and Reproductive Traits of Blanding's Turtles, Emydoidea blandingii, at the Western Edge of the Species' Range. COPEIA 2008. [DOI: 10.1643/ce-07-108] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rollinson N, Brooks RJ. Sources and Significance of Among-Individual Reproductive Variation in a Northern Population of Painted Turtles (Chrysemys picta). COPEIA 2008. [DOI: 10.1643/ce-06-203] [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]
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Litzgus JD, Bolton F, Schulte-Hostedde AI. Reproductive Output Depends on Body Condition in Spotted Turtles (Clemmys Guttata). COPEIA 2008. [DOI: 10.1643/ch-07-093] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Rollinson N, Brooks RJ. Optimal offspring provisioning when egg size is “constrained”: a case study with the painted turtle Chrysemys picta. OIKOS 2007. [DOI: 10.1111/j.2007.0030-1299.16088.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Daza JM, Páez VP. MORPHOMETRIC VARIATION AND ITS EFFECT ON REPRODUCTIVE POTENTIAL IN FEMALE COLOMBIAN SLIDER TURTLES (TRACHEMYS CALLIROSTRIS CALLIROSTRIS). HERPETOLOGICA 2007. [DOI: 10.1655/0018-0831(2007)63[125:mvaieo]2.0.co;2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Myers EM, Janzen FJ, Adams DC, Tucker JK. QUANTITATIVE GENETICS OF PLASTRON SHAPE IN SLIDER TURTLES (
TRACHEMYS SCRIPTA
). Evolution 2007. [DOI: 10.1111/j.0014-3820.2006.tb01137.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Erin M. Myers
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011
| | - Fredric J. Janzen
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011
| | - Dean C. Adams
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, Iowa 50011
- Department of Statistics, Iowa State University, Ames, Iowa 50011
| | - John K. Tucker
- Illinois Natural History Survey, 8450 Montclair Avenue, Brighton, Illinois 62012
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Loehr VJT, Hofmeyr MD, Henen BT. Growing and shrinking in the smallest tortoise, Homopus signatus signatus: the importance of rain. Oecologia 2007; 153:479-88. [PMID: 17453250 DOI: 10.1007/s00442-007-0738-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 03/21/2007] [Indexed: 11/24/2022]
Abstract
Climate change models predict that the range of the world's smallest tortoise, Homopus signatus signatus, will aridify and contract in the next decades. To evaluate the effects of annual variation in rainfall on the growth of H. s. signatus, we recorded annual growth rates of wild individuals from spring 2000 to spring 2004. Juveniles grew faster than did adults, and females grew faster than did males. Growth correlated strongly with the amount of rain that fell during the time just before and within the growth periods. Growth rates were lowest in 2002-2003, when almost no rain fell between September 2002 and August 2003. In this period, more than 54% of the tortoises had negative growth rates for their straight carapace length (SCL), shell height (SH), and shell volume (SV); maximum shrinking for SCL, SH, and SV was 4, 11, and 12%, respectively. The shell of H. s. signatus has some flexibility dorso-ventrally, so a reduction in internal matter due to starvation or dehydration may have caused SH to shrink. Because the length and width of the shell seem more rigid, reversible bone resorption may have contributed to shrinkage, particularly of the shell width and plastron length. Based on growth rates for all years, female H. s. signatus need 11-12 years to mature, approximately twice as long as would be expected allometrically for such a small species. However, if aridification lowers average growth rates to the level of 2002-2003, females would require 30 years to mature. Additionally, aridification would lower average and maximum female size, resulting in smaller eggs and hatchlings. These projected life history responses to aridification heighten the threat posed by the predicted range contraction of this red-listed species.
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Affiliation(s)
- Victor J T Loehr
- Homopus Research Foundation, Kwikstaartpad 1, 3403 ZH, IJsselstein, Netherlands.
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Myers EM, Janzen FJ, Adams DC, Tucker JK. QUANTITATIVE GENETICS OF PLASTRON SHAPE IN SLIDER TURTLES (TRACHEMYS SCRIPTA). Evolution 2006. [DOI: 10.1554/05-633.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Wilkinson LR, Gibbons JW. Patterns of Reproductive Allocation: Clutch and Egg Size Variation in Three Freshwater Turtles. COPEIA 2005. [DOI: 10.1643/0045-8511(2005)005[0868:poraca]2.0.co;2] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hofmeyr MD, Henen BT, Loehr VJ. Overcoming environmental and morphological constraints: egg size and pelvic kinesis in the smallest tortoise, Homopus signatus. CAN J ZOOL 2005. [DOI: 10.1139/z05-132] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The small tortoises of southern Africa include the only testudinid taxa that produce single-egg clutches. This group includes the world's smallest tortoise, Homopus signatus (Gmelin, 1789), which inhabits a harsh, arid environment. Climate and body size may influence reproductive output, so we hypothesized that the east–west aridity gradient in southern Africa affects egg and clutch size of the small indigenous tortoises, and that the morphology of H. signatus constrains egg size, preventing the formation of optimal eggs. Here we show that aridity and unpredictable rainfall determine which of these tortoise taxa produce single-egg clutches. Taxa in less predictable environments produce larger eggs relative to body size than do taxa in more predictable environments. Homopus signatus produces the largest egg relative to body size, probably to enhance offspring survival in its harsh environment. Body size, pelvic aperture size, and the narrow anal gap of H. signatus appear to constrain egg size. Despite these constraints, females produce rigid-shelled eggs larger than the pelvic canal and use pelvic kinesis to pass eggs at oviposition; both features are unknown in other chelonians and emphasize the selective advantage of large eggs to H. signatus.
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BOWDEN RM, HARMS HK, PAITZ RT, JANZEN FJ. Does optimal egg size vary with demographic stage because of a physiological constraint? Funct Ecol 2004. [DOI: 10.1111/j.0269-8463.2004.00861.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Twice every second year: reproduction in the pig-nosed turtle, Carettochelys insculpta, in the wet–dry tropics of Australia. J Zool (1987) 2003. [DOI: 10.1017/s0952836902003217] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Christians JK. Avian egg size: variation within species and inflexibility within individuals. Biol Rev Camb Philos Soc 2002; 77:1-26. [PMID: 11911371 DOI: 10.1017/s1464793101005784] [Citation(s) in RCA: 266] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Egg size is a widely-studied trait and yet the causes and consequences of variation in this trait remain poorly understood. Egg size varies greatly within many avian species, with the largest egg in a population generally being at least 50% bigger, and sometimes twice as large, as the smallest. Generally, approximately 70% of the variation in egg mass is due to variation between rather than within clutches, although there are some cases of extreme intra-clutch egg-size variation. Despite the large amount of variation in egg size between females, this trait is highly consistent within individuals between breeding attempts; the repeatability of egg size is generally above 0.6 and tends to be higher than that of clutch size or laying date. Heritability estimates also tend to be much higher for egg size (> 0.5) than for clutch size or laying date (< 0.5). As expected, given the high repeatability and heritability of egg size, supplemental food had no statistically significant effect on this trait in 18 out of 28 (64%) studies. Where dietary supplements do increase egg size, the effect is never more than 13% of the control values and is generally much less. Similarly, ambient temperature during egg formation generally explains less than 15% of the variation in egg size. In short, egg size appears to be a characteristic of individual females, and yet the traits of a female that determine egg size are not clear. Although egg size often increases with female age (17 out of 37 studies), the change in egg size is generally less than 10%. Female mass and size rarely explain more than 20% of the variation in egg size within species. A female's egg size is not consistently related to other aspects of reproductive performance such as clutch size, laying date, or the pair's ability to rear young. Physiological characteristics of the female (e.g. endogenous protein stores, oviduct mass, rate of protein uptake by ovarian follicles) show more promise as potential determinants of egg size. With regards to the consequences of egg-size variation for offspring fitness, egg size is often correlated with offspring mass and size within the first week after hatching, but the evidence for more long-lasting effects on chick growth and survival is equivocal. In other oviparous vertebrates, the magnitude of egg-size variation within populations is often as great or greater than that observed within avian populations. Although there are much fewer estimates of the repeatability of egg size in other taxa, the available evidence suggests that egg size may be more flexible within individuals. Furthermore, in non-avian species (particularly fish and turtles), it is more common for female mass or size to explain a substantial proportion of the variation in egg size. Further research into the physiological basis of egg-size variation is needed to shed light on both the proximate and ultimate causes of intraspecific variation in this trait in birds.
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Affiliation(s)
- Julian K Christians
- Department of Biological Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
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