1
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Iverson JB. Climate-Mediated Recruitment Failure in a Turtle Population and Its Bearing on Northern Limits of Distribution. CHELONIAN CONSERVATION AND BIOLOGY 2022. [DOI: 10.2744/ccb-1554.1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- John B. Iverson
- Department of Biology, Earlham College, Richmond, Indiana 47374 USA []
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2
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Hedrick AR, Greene DU, Lewis EL, Hood AS, Iverson JB. Climate effects on nesting phenology in Nebraska turtles. Ecol Evol 2021; 11:1225-1239. [PMID: 33598126 PMCID: PMC7863389 DOI: 10.1002/ece3.7105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 10/29/2020] [Accepted: 11/04/2020] [Indexed: 12/03/2022] Open
Abstract
A frequent response of organisms to climate change is altering the timing of reproduction, and advancement of reproductive timing has been a common reaction to warming temperatures in temperate regions. We tested whether this pattern applied to two common North American turtle species over the past three decades in Nebraska, USA. The timing of nesting (either first date or average date) of the Common Snapping Turtle (Chelydra serpentina) was negatively correlated with mean December maximum temperatures of the preceding year and mean May minimum and maximum temperatures in the nesting year and positively correlated with precipitation in July of the previous year. Increased temperatures during the late winter and spring likely permit earlier emergence from hibernation, increased metabolic rates and feeding opportunities, and accelerated vitellogenesis, ovulation, and egg shelling, all of which could drive earlier nesting. However, for the Painted Turtle (Chrysemys picta), the timing of nesting was positively correlated with mean minimum temperatures in September, October, December of the previous year, February of the nesting year, and April precipitation. These results suggest warmer fall, and winter temperature may impose an increased metabolic cost to painted turtles that impedes fall vitellogenesis, and April rains may slow the completion of vitellogenesis through decreased basking opportunities. For both species, nest deposition was highly correlated with body size, and larger females nested earlier in the season. Although average annual ambient temperatures have increased over the last four decades of our overall fieldwork at our study site, spring temperatures have not yet increased, and hence, nesting phenology has not advanced at our site for Chelydra. While Chrysemys exhibited a weak trend toward later nesting, this response was likely due to increased recruitment of smaller females into the population due to nest protection and predator control (Procyon lotor) in the early 2000s. Should climate change result in an increase in spring temperatures, nesting phenology would presumably respond accordingly, conditional on body size variation within these populations.
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Affiliation(s)
- Ashley R. Hedrick
- Department of BiologyEarlham CollegeRichmondINUSA
- Department of Ecology, Evolution, and Organismal BiologyIowa State UniversityAmesIAUSA
| | | | - Erin L. Lewis
- Department of BiologyEarlham CollegeRichmondINUSA
- Department of BiologyUtah State UniversityLoganUTUSA
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3
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Moldowan PD, Brooks RJ, Litzgus JD. Sex, shells, and weaponry: coercive reproductive tactics in the painted turtle, Chrysemys picta. Behav Ecol Sociobiol 2020. [DOI: 10.1007/s00265-020-02926-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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4
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Taylor EN, Diele‐Viegas LM, Gangloff EJ, Hall JM, Halpern B, Massey MD, Rödder D, Rollinson N, Spears S, Sun B, Telemeco RS. The thermal ecology and physiology of reptiles and amphibians: A user's guide. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 335:13-44. [DOI: 10.1002/jez.2396] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 02/05/2023]
Affiliation(s)
- Emily N. Taylor
- Biological Sciences Department California Polytechnic State University San Luis Obispo California
| | | | | | - Joshua M. Hall
- Department of Biological Sciences Auburn University Auburn Alabama
| | | | - Melanie D. Massey
- Department of Biology Dalhousie University Halifax Nova Scotia Canada
| | - Dennis Rödder
- Zoologisches Forschungsmuseum Alexander Koenig Bonn Germany
| | - Njal Rollinson
- Department of Ecology and Evolutionary Biology University of Toronto St. Toronto Ontario Canada
- School of the Environment University of Toronto Toronto Ontario Canada
| | - Sierra Spears
- Department of Zoology Ohio Wesleyan University Delaware Ohio
| | - Bao‐jun Sun
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology Chinese Academy of Sciences Beijing China
| | - Rory S. Telemeco
- Department of Biology California State University Fresno California
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5
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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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6
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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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7
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Abstract
Climate change is occurring at an unprecedented rate and has begun to modify the distribution and phenology of organisms worldwide. Chelonians are expected to be particularly vulnerable due to limited dispersal capabilities as well as widespread temperature-dependent sex determination. The number of papers published about the effects of climate change on turtles has increased exponentially over the last decade; here, I review the data from peer-reviewed publications to assess the likely impacts of climate change on individuals, populations, and communities. Based upon these studies future research should focus on: (1) Individual responses to climate change, particularly with respect to thermal biology, phenology, and microhabitat selection; (2) improving species distribution models by incorporating fine-scale environmental variables as well as physiological processes; (3) identifying the consequences of skewed sex ratios; and (4) assessments of community resilience and the development of methods to mitigate climate change impacts. Although detailed management recommendations are not possible at this point, careful consideration should be given regarding how to manage low vagility species as habitats shift poleward. In the worst-case scenario, proactive management may be required in order to ensure that widespread losses do not occur.
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8
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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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9
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Janzen FJ, Hoekstra LA, Brooks RJ, Carroll DM, Gibbons JW, Greene JL, Iverson JB, Litzgus JD, Michael ED, Parren SG, Roosenburg WM, Strain GF, Tucker JK, Ultsch GR. Altered spring phenology of North American freshwater turtles and the importance of representative populations. Ecol Evol 2018; 8:5815-5827. [PMID: 29938095 PMCID: PMC6010881 DOI: 10.1002/ece3.4120] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 03/22/2018] [Accepted: 03/29/2018] [Indexed: 12/25/2022] Open
Abstract
Globally, populations of diverse taxa have altered phenology in response to climate change. However, most research has focused on a single population of a given taxon, which may be unrepresentative for comparative analyses, and few long-term studies of phenology in ectothermic amniotes have been published. We test for climate-altered phenology using long-term studies (10-36 years) of nesting behavior in 14 populations representing six genera of freshwater turtles (Chelydra, Chrysemys, Kinosternon, Malaclemys, Sternotherus, and Trachemys). Nesting season initiation occurs earlier in more recent years, with 11 of the populations advancing phenology. The onset of nesting for nearly all populations correlated well with temperatures during the month preceding nesting. Still, certain populations of some species have not advanced phenology as might be expected from global patterns of climate change. This collection of findings suggests a proximate link between local climate and reproduction that is potentially caused by variation in spring emergence from hibernation, ability to process food, and thermoregulatory opportunities prior to nesting. However, even though all species had populations with at least some evidence of phenological advancement, geographic variation in phenology within and among turtle species underscores the critical importance of representative data for accurate comprehensive assessments of the biotic impacts of climate change.
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Affiliation(s)
- Fredric J. Janzen
- Department of Ecology, Evolution & Organismal BiologyIowa State UniversityAmesIowa
| | - Luke A. Hoekstra
- Department of Ecology, Evolution & Organismal BiologyIowa State UniversityAmesIowa
| | - Ronald J. Brooks
- Department of Integrative BiologyUniversity of GuelphGuelphONCanada
| | | | | | | | | | | | - Edwin D. Michael
- Division of Forestry and Natural ResourcesWest Virginia UniversityMorgantownWest Virginia
| | | | | | | | - John K. Tucker
- Jerry F. Costello National Great Rivers Research and Education Center Confluence Field StationEast AltonIllinois
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10
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Santilli J, Rollinson N. Toward a general explanation for latitudinal clines in body size among chelonians. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly054] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Jessica Santilli
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
| | - Njal Rollinson
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, ON, Canada
- School of the Environment, University of Toronto, Toronto, ON, Canada
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11
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Rollinson N, Holt SM, Massey MD, Holt RC, Nancekivell EG, Brooks RJ. A new method of estimating thermal performance of embryonic development rate yields accurate prediction of embryonic age in wild reptile nests. J Therm Biol 2018; 74:187-194. [PMID: 29801626 DOI: 10.1016/j.jtherbio.2018.03.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 02/26/2018] [Accepted: 03/09/2018] [Indexed: 11/18/2022]
Abstract
Temperature has a strong effect on ectotherm development rate. It is therefore possible to construct predictive models of development that rely solely on temperature, which have applications in a range of biological fields. Here, we leverage a reference series of development stages for embryos of the turtle Chelydra serpentina, which was described at a constant temperature of 20 °C. The reference series acts to map each distinct developmental stage onto embryonic age (in days) at 20 °C. By extension, an embryo taken from any given incubation environment, once staged, can be assigned an equivalent age at 20 °C. We call this concept "Equivalent Development", as it maps the development stage of an embryo incubated at a given temperature to its equivalent age at a reference temperature. In the laboratory, we used the concept of Equivalent Development to estimate development rate of embryos of C. serpentina across a series of constant temperatures. Using these estimates of development rate, we created a thermal performance curve measured in units of Equivalent Development (TPCED). We then used the TPCED to predict developmental stage of embryos in several natural turtle nests across six years. We found that 85% of the variation of development stage in natural nests could be explained. Further, we compared the predictive accuracy of the model based on the TPCED to the predictive accuracy of a degree-day model, where development is assumed to be linearly related to temperature and the amount of accumulated heat is summed over time. Information theory suggested that the model based on the TPCED better describes variation in developmental stage in wild nests than the degree-day model. We suggest the concept of Equivalent Development has several strengths and can be broadly applied. In particular, studies on temperature-dependent sex determination may be facilitated by the concept of Equivalent Development, as development age maps directly onto the developmental series of the organism, allowing critical periods of sex determination to be delineated without invasive sampling, even under fluctuating temperature.
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Affiliation(s)
- Njal Rollinson
- Department of Ecology and Evolutionary Biology. University of Toronto, 25 Willcocks St., Toronto, ON, Canada M5S 3B2; School of the Environment, University of Toronto, 33 Willcocks Street, Toronto, ON, Canada M5S 3E8
| | - Sarah M Holt
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Melanie D Massey
- Department of Ecology and Evolutionary Biology. University of Toronto, 25 Willcocks St., Toronto, ON, Canada M5S 3B2
| | - Richard C Holt
- School of Computer Science, University of Waterloo, Waterloo, Canada N2L 3G1
| | - E Graham Nancekivell
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
| | - Ronald J Brooks
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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12
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Hedrick A, Klondaris H, Corichi L, Dreslik M, Iverson J. The effects of climate on annual variation in reproductive output in Snapping Turtles (Chelydra serpentina). CAN J ZOOL 2018. [DOI: 10.1139/cjz-2016-0321] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reptiles are highly dependent on climatic patterns to regulate their behavior and physiology, and studies of the effects of climate on the biology of organisms are increasingly important given expected climate change. Our study examined the effects of climate variation over 15 of the 26 years between 1990 and 2015 on the reproductive output of the Snapping Turtle (Chelydra serpentina (Linnaeus, 1758)). Egg mass, clutch size, and clutch mass (relative to body size) were significantly higher in years following warmer temperatures in September and October of the year before reproduction, but not related to temperatures in April and May just before reproduction. Of the above life-history traits, egg mass varied the least across years, and after warm autumns small turtles (225–285 mm carapace length) increased clutch mass by increasing clutch size but not egg mass. In contrast, under the same conditions, large turtles increased clutch mass by increasing egg mass but not clutch size. Our data suggest optimal egg mass may vary with female size. Climate change may already have impacted reproductive output in Snapping Turtles at the site because temperatures during September and October have increased about 0.5 °C each decade for the last 45 years.
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Affiliation(s)
- A.R. Hedrick
- Department of Biology, Earlham College, Richmond, IN 47374, USA
| | - H.M. Klondaris
- Department of Biology, Earlham College, Richmond, IN 47374, USA
| | - L.C. Corichi
- Department of Biology, Earlham College, Richmond, IN 47374, USA
| | - M.J. Dreslik
- Illinois Natural History Survey, Prairie Research Institute, University of Illinois, Champaign, IL 61820, USA
| | - J.B. Iverson
- Department of Biology, Earlham College, Richmond, IN 47374, USA
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13
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Armstrong DP, Keevil MG, Rollinson N, Brooks RJ. Subtle individual variation in indeterminate growth leads to major variation in survival and lifetime reproductive output in a long‐lived reptile. Funct Ecol 2017. [DOI: 10.1111/1365-2435.13014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Doug P. Armstrong
- Wildlife Ecology GroupMassey University Palmerston North New Zealand
| | | | - Njal Rollinson
- Department of Ecology & Evolutionary BiologyUniversity of Toronto Toronto Ontario Canada
- School of the EnvironmentUniversity of Toronto Toronto Ontario Canada
| | - Ronald J. Brooks
- Department of Integrative BiologyUniversity of Guelph Guelph Ontario Canada
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14
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Thompson DM, Ligon DB, Patton JC, Papeş M. Effects of life-history requirements on the distribution of a threatened reptile. CONSERVATION BIOLOGY : THE JOURNAL OF THE SOCIETY FOR CONSERVATION BIOLOGY 2017; 31:427-436. [PMID: 27488734 DOI: 10.1111/cobi.12800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2016] [Revised: 06/04/2016] [Accepted: 07/18/2016] [Indexed: 06/06/2023]
Abstract
Survival and reproduction are the two primary life-history traits essential for species' persistence; however, the environmental conditions that support each of these traits may not be the same. Despite this, reproductive requirements are seldom considered when estimating species' potential distributions. We sought to examine potentially limiting environmental factors influencing the distribution of an oviparous reptile of conservation concern with respect to the species' survival and reproduction and to assess the implications of the species' predicted climatic constraints on current conservation practices. We used ecological niche modeling to predict the probability of environmental suitability for the alligator snapping turtle (Macrochelys temminckii). We built an annual climate model to examine survival and a nesting climate model to examine reproduction. We combined incubation temperature requirements, products of modeled soil temperature data, and our estimated distributions to determine whether embryonic development constrained the northern distribution of the species. Low annual precipitation constrained the western distribution of alligator snapping turtles, whereas the northern distribution was constrained by thermal requirements during embryonic development. Only a portion of the geographic range predicted to have a high probability of suitability for alligator snapping turtle survival was estimated to be capable of supporting successful embryonic development. Historic occurrence records suggest adult alligator snapping turtles can survive in regions with colder climes than those associated with consistent and successful production of offspring. Estimated egg-incubation requirements indicated that current reintroductions at the northern edge of the species' range are within reproductively viable environmental conditions. Our results highlight the importance of considering survival and reproduction when estimating species' ecological niches, implicating conservation plans, and benefits of incorporating physiological data when evaluating species' distributions.
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Affiliation(s)
- Denise M Thompson
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, U.S.A
| | - Day B Ligon
- Department of Biology, Missouri State University, 901 South National Avenue, Springfield, MO, 65897, U.S.A
| | - Jason C Patton
- Department of Plant and Soil Sciences, Oklahoma State University, 272D Agriculture Hall, Stillwater, OK, 74078, U.S.A
| | - Monica Papeş
- Department of Integrative Biology, Oklahoma State University, 501 Life Sciences West, Stillwater, OK, 74078, U.S.A
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15
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Edge CB, Rollinson N, Brooks RJ, Congdon JD, Iverson JB, Janzen FJ, Litzgus JD. Phenotypic plasticity of nest timing in a post-glacial landscape: how do reptiles adapt to seasonal time constraints? Ecology 2017; 98:512-524. [PMID: 27870008 DOI: 10.1002/ecy.1665] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 10/12/2016] [Accepted: 11/09/2016] [Indexed: 11/09/2022]
Abstract
Life histories evolve in response to constraints on the time available for growth and development. Nesting date and its plasticity in response to spring temperature may therefore be important components of fitness in oviparous ectotherms near their northern range limit, as reproducing early provides more time for embryos to complete development before winter. We used data collected over several decades to compare air temperature and nest date plasticity in populations of painted turtles and snapping turtles from a relatively warm environment (southeastern Michigan) near the southern extent of the last glacial maximum to a relatively cool environment (central Ontario) near the northern extent of post-glacial recolonization. For painted turtles, population-level differences in reaction norm elevation for two phenological traits were consistent with adaptation to time constraints, but no differences in reaction norm slopes were observed. For snapping turtle populations, the difference in reaction norm elevation for a single phenological trait was in the opposite direction of what was expected under adaptation to time constraints, and no difference in reaction norm slope was observed. Finally, among-individual variation in individual plasticity for nesting date was detected only in the northern population of snapping turtles, suggesting that reaction norms are less canalized in this northern population. Overall, we observed evidence of phenological adaptation, and possibly maladaptation, to time constraints in long-lived reptiles. Where present, (mal)adaptation occurred by virtue of differences in reaction norm elevation, not reaction norm slope. Glacial history, generation time, and genetic constraint may all play an important role in the evolution of phenological timing and its plasticity in long-lived reptiles.
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Affiliation(s)
- Christopher B Edge
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Njal Rollinson
- Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3G5, Canada
| | - Ronald J Brooks
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Justin D Congdon
- Savannah River Ecology Laboratory, Aiken, South Carolina, 29802, USA
| | - John B Iverson
- Department of Biology, Earlham College, Richmond, Indiana, 47374, USA
| | - Fredric J Janzen
- Department of Ecology, Evolution and Organismal Biology, Iowa State University, Ames, Iowa, 50011, USA
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16
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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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17
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Costa ZJ. Responses to Predators Differ Between Native and Invasive Freshwater Turtles: Environmental Context and its Implications for Competition. Ethology 2014. [DOI: 10.1111/eth.12235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- Zacharia J. Costa
- Department of Biology; Virginia Commonwealth University; Richmond VA USA
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18
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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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19
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Rollinson N, Hutchings JA. Environmental Quality Predicts Optimal Egg Size in the Wild. Am Nat 2013; 182:76-90. [DOI: 10.1086/670648] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Rollinson N, Edge CB, Brooks RJ. Recurrent violations of invariant rules for offspring size: evidence from turtles and the implications for small clutch size models. Oecologia 2013; 172:973-82. [PMID: 23277212 DOI: 10.1007/s00442-012-2565-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 12/11/2012] [Indexed: 11/30/2022]
Abstract
Smith and Fretwell's classic model predicts that parents can maximize fitness by dividing the energy available for reproduction into offspring of an optimal size. However, this model breaks down when clutch size is small (~1-10 offspring). Invariant rules are an extension of the Smith-Fretwell model, and these rules predict how offspring size will vary among and within individuals that produce small clutch sizes. Here, we provide a narrow test of invariant rules using three turtle species, then we synthesize and re-analyze existing data from 18 different species (comprising five Orders) to evaluate whether invariant rules are followed across broad taxa. We do not find support for most invariant rules in turtles, and our re-analysis demonstrates a general mismatch between observed and expected values across all taxa evaluated, suggesting that invariant rules fail to predict reproductive patterns in nature. Morphological constraints on offspring size and reproductive effort may be important reasons for disparities between theory and observation both in turtles and other taxa. Paradoxically, morphological constraints are most common in small-bodied species and individuals, but these same candidates are also those which produce the small clutch sizes that are necessary to test invariant rules, such that a fair test of invariant rules will often be challenging. Mismatches between theory and observation might also occur because theory assumes that mothers exert control over resource allocation to offspring. In fact, there is evidence of widespread genetic correlations among investment per offspring and reproductive effort, such that these traits are not independent.
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Affiliation(s)
- Njal Rollinson
- Department of Biology, Dalhousie University, Halifax, NS, Canada
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