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Marn N, Kooijman SALM. The comparative energetics of the turtles and crocodiles. Ecol Evol 2022; 12:e8996. [PMID: 35784053 PMCID: PMC9188023 DOI: 10.1002/ece3.8996] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Revised: 04/15/2022] [Accepted: 04/20/2022] [Indexed: 11/24/2022] Open
Abstract
The Add‐my‐Pet collection of data on energetics and Dynamic Energy Budget parameters currently contains 92 species of turtles and 23 species of crocodiles. We discuss patterns of eco‐physiological traits of turtles and crocodiles, as functions of parameter values, and compare them with other taxa. Turtles and crocodiles accurately match the general rule that the life‐time cumulated neonate mass production equals ultimate weight. The weight at birth for reptiles scales with ultimate weight to the power 0.6. The scaling exponent is between that of amphibians and birds, while that for mammals is close to 1. We explain why this points to limitations imposed by embryonic respiration, the role of water stress and the accumulation of nitrogen waste during the embryo stage. Weight at puberty is proportional to ultimate weight, and is the largest for crocodiles, followed by that of turtles. These facts explain why the precociality coefficient, sHbp—approximated by the ratio of weight at birth and weight at puberty at abundant food—decreases with ultimate weight. It is the smallest for crocodiles because of their large size and is smaller for turtles than for lizards and snakes. The sea turtles have a smaller sHbp than the rest of the turtles, linked to their large size and small offspring size. We link their small weight and age at birth to reducing risks on the beach. The maximum reserve capacity in both turtles and crocodiles clearly decreases with the precociality coefficient. This relationship has not been found that clearly in other taxa, not even in other reptiles, with the exception of the chondrichthyans. Among reptiles, crocodiles and sea turtles have a relatively large assimilation rate and a large reserve capacity.
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Affiliation(s)
- Nina Marn
- Division for Marine and Environmental Research Rudjer Boskovic Institute Zagreb Croatia.,School of Biological Sciences The University of Western Australia Crawley WA Australia
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Mitchell CI, Friend DA, Phillips LT, Hunter EA, Lovich JE, Agha M, Puffer SR, Cummings KL, Medica PA, Esque TC, Nussear KE, Shoemaker KT. ‘Unscrambling’ the drivers of egg production in Agassiz’s desert tortoise: climate and individual attributes predict reproductive output. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The ‘bet hedging’ life history strategy of long-lived iteroparous species reduces short-term reproductive output to minimize the risk of reproductive failure over a lifetime. For desert-dwelling ectotherms living in variable and unpredictable environments, reproductive output is further influenced by precipitation and temperature via effects on food availability and limits on activity. We assembled multiple (n = 12) data sets on egg production for the threatened Agassiz’s desert tortoise Gopherus agassizii across its range and used these data to build a range-wide predictive model of annual reproductive output as a function of annual weather variation and individual-level attributes (body size and prior-year reproductive status). Climate variables were more robust predictors of reproductive output than individual-level attributes, with overall reproductive output positively related to prior-year precipitation and an earlier start to the spring activity season, and negatively related to spring temperature extremes (monthly temperature range in March-April). Reproductive output was highest for individuals with larger body sizes that reproduced in the previous year. Expected annual reproductive output from 1990-2018 varied from 2-5 to 6-12 eggs female-1 yr-1 , with a weak decline in expected reproductive output over this time (p = 0.02). Climate-driven environmental variation in expected reproductive output was highly correlated across all 5 Recovery Units for this species (Pearson’s r > 0.9). Overall, our model suggests that climate change could strongly impact the reproductive output of Agassiz’s desert tortoise, and could have a negative population-level effect if precipitation is significantly reduced across the species’ range as predicted under some climate models.
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Affiliation(s)
- CI Mitchell
- Department of Geography, University of Nevada, Reno, NV 89557, USA
- Desert Centered Ecology, LLC, Tucson, AZ 85716, USA
| | - DA Friend
- Department of Geography, University of Nevada, Reno, NV 89557, USA
| | - LT Phillips
- Department of Geography, University of Nevada, Reno, NV 89557, USA
| | - EA Hunter
- Department of Biology, Georgia Southern University, Statesboro, GA 30460, USA
| | - JE Lovich
- US Geological Survey Southwest Biological Science Center, Flagstaff, AZ 86001, USA
| | - M Agha
- Washington Department of Fish and Wildlife, Olympia, WA 98501, USA
| | - SR Puffer
- US Geological Survey Southwest Biological Science Center, Flagstaff, AZ 86001, USA
| | - KL Cummings
- US Geological Survey Southwest Biological Science Center, Flagstaff, AZ 86001, USA
| | - PA Medica
- US Geological Survey Western Ecological Research Center, Henderson, NV 89074, USA
| | - TC Esque
- US Geological Survey Western Ecological Research Center, Henderson, NV 89074, USA
| | - KE Nussear
- Department of Geography, University of Nevada, Reno, NV 89557, USA
| | - KT Shoemaker
- Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV 89557, USA
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Coleman AT. Urban Turtle Project: Using Citizen Science to Document Freshwater Turtle Communities and Populations in Birmingham, Alabama, with Focus on Alabama Map Turtles (Graptemys pulchra). CHELONIAN CONSERVATION AND BIOLOGY 2020. [DOI: 10.2744/ccb-1427.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Andrew T. Coleman
- Talladega College, Talladega, Alabama 35160 USA []; Urban Turtle Project []
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López-Pérez JE, Meylan PA, Goessling JM. Sex-based trade-offs in the innate and acquired immune systems of Sternotherus minor. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2020; 333:820-828. [PMID: 33075211 DOI: 10.1002/jez.2424] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 11/08/2022]
Abstract
Longevity patterns in most vertebrates suggest that females benefit most from maintenance investment. A reversed longevity pattern in loggerhead musk turtles (Sternotherus minor) allowed us to test trade-offs between maintenance and survivorship. We tested the hypothesis that the sex with greater longevity has greater maintenance than the sex with shorter longevity. We also compared the following parameters between sexes: Bactericidal ability (BA) and heterophil:lymphocyte ratios (HLR). Baseline blood samples were collected from turtles in the field; a subset of turtles was returned to a laboratory for experiments of acquired immune responses to sheep red blood cells (SRBC). We found no support for the original hypothesis of reversal in sex-dependent immune trade-offs (difference between sex SRBC titers: p = .102; interaction between treatment and sex: p = .177; difference between treatments: p < .001; effect of sex on BA: p = .830; effect of sex on HLR: p = .717). However, we did find support for sex-dependent differences in immunity in the relationship between HLR and body condition (BCI) (effect of BCI on HLR: p = .015). In field conditions, we found that males with higher body condition indices express stressed phenotypes more than males with lower body condition indices (p = .002). However, females expressed similar stress loads across all body conditions (p = .900). Testosterone concentrations were assayed in free-living turtles and were not related to any of the immune parameters. Our results suggest that the immune systems play an important role in balancing sex-specific responses to different selective pressures in S. minor.
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Affiliation(s)
- Jorge E López-Pérez
- Department of Biological Sciences, Eckerd College, Saint Petersburg, Florida, USA.,Current affiliation: Southeastern Louisiana University, Louisiana, USA
| | - Peter A Meylan
- Department of Biological Sciences, Eckerd College, Saint Petersburg, Florida, USA
| | - Jeffrey M Goessling
- Department of Biological Sciences, Eckerd College, Saint Petersburg, Florida, USA
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Affiliation(s)
- J. Whitfield Gibbons
- University of Georgia, Savannah River Ecology Laboratory, Drawer E, Aiken, SC 29802, USA
| | - Jeffrey E. Lovich
- US Geological Survey, Southwest Biological Science Center, 2255 North Gemini Drive MS-9394, Flagstaff, AZ 86001-1600, USA
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