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Smaga CR, Bock SL, Johnson JM, Rainwater T, Singh R, Deem V, Letter A, Brunell A, Parrott BB. The influence of incubation temperature on offspring traits varies across northern and southern populations of the American alligator ( Alligator mississippiensis). Ecol Evol 2024; 14:e10915. [PMID: 38371857 PMCID: PMC10869887 DOI: 10.1002/ece3.10915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Revised: 01/10/2024] [Accepted: 01/15/2024] [Indexed: 02/20/2024] Open
Abstract
Maternal provisioning and the developmental environment are fundamental determinants of offspring traits, particularly in oviparous species. However, the extent to which embryonic responses to these factors differ across populations to drive phenotypic variation is not well understood. Here, we examine the contributions of maternal provisioning and incubation temperature to hatchling morphological and metabolic traits across four populations of the American alligator (Alligator mississippiensis), encompassing a large portion of the species' latitudinal range. Our results show that whereas the influence of egg mass is generally consistent across populations, responses to incubation temperature show population-level variation in several traits, including mass, head length, head width, and residual yolk mass. Additionally, the influence of incubation temperature on developmental rate is greater at northern populations, while the allocation of maternal resources toward fat body mass is greater at southern populations. Overall, our results suggest that responses to incubation temperature, relative to maternal provisioning, are a larger source of interpopulation phenotypic variation and may contribute to the local adaptation of populations.
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Affiliation(s)
- Christopher R. Smaga
- Eugene P. Odum School of EcologyUniversity of GeorgiaAthensGeorgiaUSA
- The University of Georgia's Savannah River Ecology LaboratoryAikenSouth CarolinaUSA
| | - Samantha L. Bock
- Eugene P. Odum School of EcologyUniversity of GeorgiaAthensGeorgiaUSA
- The University of Georgia's Savannah River Ecology LaboratoryAikenSouth CarolinaUSA
| | - Josiah M. Johnson
- Eugene P. Odum School of EcologyUniversity of GeorgiaAthensGeorgiaUSA
- The University of Georgia's Savannah River Ecology LaboratoryAikenSouth CarolinaUSA
| | - Thomas Rainwater
- Belle W. Baruch Institute of Coastal Ecology and Forest ScienceClemson UniversityGeorgetownSouth CarolinaUSA
- Tom Yawkey Wildlife CenterGeorgetownSouth CarolinaUSA
| | - Randeep Singh
- Belle W. Baruch Institute of Coastal Ecology and Forest ScienceClemson UniversityGeorgetownSouth CarolinaUSA
| | - Vincent Deem
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation CommissionGainesvilleFloridaUSA
| | - Andrew Letter
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation CommissionGainesvilleFloridaUSA
| | - Arnold Brunell
- Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation CommissionGainesvilleFloridaUSA
| | - Benjamin B. Parrott
- Eugene P. Odum School of EcologyUniversity of GeorgiaAthensGeorgiaUSA
- The University of Georgia's Savannah River Ecology LaboratoryAikenSouth CarolinaUSA
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Grunst ML, Grunst AS, Grémillet D, Fort J. Combined threats of climate change and contaminant exposure through the lens of bioenergetics. GLOBAL CHANGE BIOLOGY 2023; 29:5139-5168. [PMID: 37381110 DOI: 10.1111/gcb.16822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Accepted: 05/17/2023] [Indexed: 06/30/2023]
Abstract
Organisms face energetic challenges of climate change in combination with suites of natural and anthropogenic stressors. In particular, chemical contaminant exposure has neurotoxic, endocrine-disrupting, and behavioral effects which may additively or interactively combine with challenges associated with climate change. We used a literature review across animal taxa and contaminant classes, but focused on Arctic endotherms and contaminants important in Arctic ecosystems, to demonstrate potential for interactive effects across five bioenergetic domains: (1) energy supply, (2) energy demand, (3) energy storage, (4) energy allocation tradeoffs, and (5) energy management strategies; and involving four climate change-sensitive environmental stressors: changes in resource availability, temperature, predation risk, and parasitism. Identified examples included relatively equal numbers of synergistic and antagonistic interactions. Synergies are often suggested to be particularly problematic, since they magnify biological effects. However, we emphasize that antagonistic effects on bioenergetic traits can be equally problematic, since they can reflect dampening of beneficial responses and result in negative synergistic effects on fitness. Our review also highlights that empirical demonstrations remain limited, especially in endotherms. Elucidating the nature of climate change-by-contaminant interactive effects on bioenergetic traits will build toward determining overall outcomes for energy balance and fitness. Progressing to determine critical species, life stages, and target areas in which transformative effects arise will aid in forecasting broad-scale bioenergetic outcomes under global change scenarios.
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Affiliation(s)
- Melissa L Grunst
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, La Rochelle, France
| | - Andrea S Grunst
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, La Rochelle, France
| | - David Grémillet
- CEFE, Univ Montpellier, CNRS, EPHE, IRD, Montpellier, France
- Percy FitzPatrick Institute of African Ornithology, University of Cape Town, Rondebosch, South Africa
| | - Jérôme Fort
- Littoral, Environnement et Sociétés (LIENSs), UMR 7266 CNRS-La Rochelle Université, La Rochelle, France
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Johnson JM, Smaga CR, Bock SL, Parrott BB. Maternal provisioning interacts with incubation temperature to affect hatchling mercury exposure in an oviparous reptile. Biol Lett 2023; 19:20230097. [PMID: 37554010 PMCID: PMC10410221 DOI: 10.1098/rsbl.2023.0097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/25/2023] [Indexed: 08/10/2023] Open
Abstract
The thermal environment experienced by developing embryos can influence the utilization of maternally provisioned resources. Despite being particularly consequential for oviparous ectotherms, these dynamics are largely unexplored within ecotoxicological frameworks. Here, we test if incubation temperature interacts with maternally transferred mercury to affect subsequent body burdens and tissue distributions of mercury in hatchling American alligators (Alligator mississippiensis). Nine clutches of alligator eggs were collected from a mercury-contaminated reservoir and incubated at either female- or male-promoting temperatures. Total mercury (THg) concentration was measured in egg yolk collected during incubation and in a suite of tissues collected from hatchlings. THg concentrations in residual yolk and blood were higher in hatchlings incubated at cooler, female-promoting temperatures compared to the warmer, male-promoting temperatures. THg concentrations in most tissues were positively correlated with THg concentrations in blood and dermis, and egg yolk THg concentration was the best predictor of THg concentration in many resultant tissues. Our results highlight a hereto unknown role of the developmental environment in mediating tissue specific uptake of contaminants in an oviparous reptile.
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Affiliation(s)
- Josiah M. Johnson
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Christopher R. Smaga
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Samantha L. Bock
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
| | - Benjamin B. Parrott
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, USA
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA
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Johnson JM, Bock SL, Smaga CR, Lambert MR, Rainwater TR, Wilkinson PM, Parrott BB. Relationships between maternally-transferred mercury and hatchling development, behavior, and survival in the American alligator (Alligator mississippiensis). THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 870:162010. [PMID: 36739038 DOI: 10.1016/j.scitotenv.2023.162010] [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: 10/27/2022] [Revised: 12/27/2022] [Accepted: 01/30/2023] [Indexed: 06/18/2023]
Abstract
Mercury is a toxic and pervasive environmental contaminant that can be transferred from mother to offspring during development. Consequences of maternally-transferred mercury have been observed in vertebrate taxa, including reduced clutch viability, reduced offspring size, and behavioral alterations. These sublethal effects have been assumed to decrease survivorship, though this is seldom assessed. Here, we examined how maternally-transferred mercury interacts with incubation temperature to influence reproductive success, offspring behavior, and subsequent survival in the American alligator (Alligator mississippiensis). We collected nine clutches of eggs from a mercury contaminated reservoir on the Savannah River Site, South Carolina, and incubated eggs at either female- or male-promoting temperatures. Clutch-averaged mercury in egg yolk was high relative to other studies in crocodilians and ranged from 0.248 to 0.554 ppm compared to 0.018-0.052 ppm at a site with low levels of mercury contamination; mercury levels in hatchling blood ranged from 0.090 to 0.490 ppm (x¯ = 0.240 ppm, n = 158). We found few, mostly negligible correlations between life history traits and mercury but noted a positive relationship with egg mass, possibly mediated by correlated maternal effects such as resource provisioning. Incubation temperature exerted strong effects on hatchling phenotypes, with warmer, male-promoting temperatures producing larger and bolder hatchlings. Presumptive females, produced from cooler incubation temperatures, spent more time in warm areas during behavior trials. Hatchlings were released 10-15 days post-hatch and surveyed over eight months to assess survival. Survivorship was positively correlated with hatchling size and negatively correlated with proportional time spent in warm areas. Presumptive females had much lower survival, and overall survivorship for the eight-month period was 0.185-0.208, depending on the modelling approach. Our study suggests that, within the range of concentrations we observed, incubation temperature has a stronger effect on offspring behavior and survival than maternally-transferred mercury pollution in American alligators.
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Affiliation(s)
- Josiah M Johnson
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, United States; Odum School of Ecology, University of Georgia, Athens, GA 30602, United States.
| | - Samantha L Bock
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, United States; Odum School of Ecology, University of Georgia, Athens, GA 30602, United States
| | - Christopher R Smaga
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, United States; Odum School of Ecology, University of Georgia, Athens, GA 30602, United States
| | - Max R Lambert
- Environmental Science, Policy, and Management, University of California, Berkeley, Berkeley, CA 94720, United States
| | - Thomas R Rainwater
- Belle W. Baruch Institute of Coastal Ecology and Forest Science, Clemson University, Georgetown, SC 29442, United States; Tom Yawkey Wildlife Center, Georgetown, SC 29440, United States
| | | | - Benjamin B Parrott
- Savannah River Ecology Laboratory, P.O. Drawer E, Aiken, SC 29802, United States; Odum School of Ecology, University of Georgia, Athens, GA 30602, United States
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Santiago E, Moreno DF, Acar M. Phenotypic plasticity as a facilitator of microbial evolution. ENVIRONMENTAL EPIGENETICS 2022; 8:dvac020. [PMID: 36465837 PMCID: PMC9709823 DOI: 10.1093/eep/dvac020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 09/27/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
Tossed about by the tides of history, the inheritance of acquired characteristics has found a safe harbor at last in the rapidly expanding field of epigenetics. The slow pace of genetic variation and high opportunity cost associated with maintaining a diverse genetic pool are well-matched by the flexibility of epigenetic traits, which can enable low-cost exploration of phenotypic space and reactive tuning to environmental pressures. Aiding in the generation of a phenotypically plastic population, epigenetic mechanisms often provide a hotbed of innovation for countering environmental pressures, while the potential for genetic fixation can lead to strong epigenetic-genetic evolutionary synergy. At the level of cells and cellular populations, we begin this review by exploring the breadth of mechanisms for the storage and intergenerational transmission of epigenetic information, followed by a brief review of common and exotic epigenetically regulated phenotypes. We conclude by offering an in-depth coverage of recent papers centered around two critical issues: the evolvability of epigenetic traits through Baldwinian adaptive phenotypic plasticity and the potential for synergy between epigenetic and genetic evolution.
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Affiliation(s)
- Emerson Santiago
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA
| | - David F Moreno
- Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA
- Systems Biology Institute, Yale University, 850 West Campus Drive, West Haven, CT 06516, USA
| | - Murat Acar
- *Correspondence address. Department of Molecular Cellular and Developmental Biology, Yale University, 219 Prospect Street, New Haven, CT 06511, USA. Tel: +90 (543) 304-0388; E-mail:
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Seebacher F. Interactive effects of anthropogenic environmental drivers on endocrine responses in wildlife. Mol Cell Endocrinol 2022; 556:111737. [PMID: 35931299 DOI: 10.1016/j.mce.2022.111737] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 07/18/2022] [Accepted: 07/26/2022] [Indexed: 10/16/2022]
Abstract
Anthropogenic activity has created unique environmental drivers, which may interact to produce unexpected effects. My aim was to conduct a systematic review of the interactive effects of anthropogenic drivers on endocrine responses in non-human animals. The interaction between temperature and light can disrupt reproduction and growth by impacting gonadotropins, thyroid hormones, melatonin, and growth hormone. Temperature and endocrine disrupting compounds (EDCs) interact to modify reproduction with differential effects across generations. The combined effects of light and EDCs can be anxiogenic, so that light-at-night could increase anxiety in wildlife. Light and noise increase glucocorticoid release by themselves, and together can modify interactions between individuals and their environment. The literature detailing interactions between drivers is relatively sparse and there is a need to extend research to a broader range of taxa and interactions. I suggest that incorporating endocrine responses into Adverse Outcome Pathways would be beneficial to improve predictions of environmental effects.
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Affiliation(s)
- Frank Seebacher
- School of Life and Environmental Sciences A08, University of Sydney, NSW, 2006, Australia.
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