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Sullivan S, Heinrich GL, Mattheus NM, Cassill D, Doody JS. Can Reptiles Use Nest Site Choice Behavior to Counter Global Warming Effects on Developing Embryos? Potential Climate Responses in a Turtle. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.825110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Climate warming is forecasted to cause extinctions, but populations could theoretically avoid extinction in a rapidly changing environment via adaptive evolution (i.e., evolutionary rescue), precluding the need for intervention. Although strong links between a changing climate and the physiology of an organism are expected, climate effects can be buffered by behavior. Nest site choice behavior, for example, can reduce environmental variation that would be experienced by embryos placed randomly with respect to environmental temperatures. We tested four provisions of this prediction by quantifying nest sites and “potential” nest sites in the Florida softshell turtle (Apalone ferox). First, turtles chose nest sites with mean canopy openness values (32–47%) that were intermediate between the shadiest (14–17%) and the sunniest potential nest sites (36–57%) available. Second, canopy openness, incident radiation intensity, and nest temperatures were generally, positively related to one another, indicating definitive thermal consequences of nest site choice. Third, our study revealed ample, cooler nest sites available to turtle mothers within close proximity to nest sites utilized; by nesting in the most shaded sites, softshell turtle mothers could depress mean nest temperatures by ∼2°C. Fourth, the growth of vegetative cover throughout incubation had negligible effects on canopy openness, incident radiation intensity, and nest temperatures, supporting the potential for mothers to “predict” developmental temperatures using temperature cues during nest site choice. Finally, our data revealed considerable variation in canopy openness chosen by nesting mothers; such behavior could thus, be subject to natural selection via embryonic mortality under future warming. Collectively, our study suggests that Florida softshell turtles, and probably other turtle species nesting in relatively open areas, may be able to counter climate change effects on developing embryos by nesting in more shaded microhabitats, assuming nest site choice behavior is heritable and can evolve at a sufficient rate to keep pace with climate warming. The evolutionary and behavioral mechanisms (e.g., assessing substrate temperatures directly vs. indirect choice of canopy cover) in the repertoire of nesting mother turtles for responding to climate warming remain elusive and are required for a more complete understanding of climate responses.
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Bock SL, Lowers RH, Rainwater TR, Stolen E, Drake JM, Wilkinson PM, Weiss S, Back B, Guillette L, Parrott BB. Spatial and temporal variation in nest temperatures forecasts sex ratio skews in a crocodilian with environmental sex determination. Proc Biol Sci 2020; 287:20200210. [PMID: 32345164 DOI: 10.1098/rspb.2020.0210] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Species displaying temperature-dependent sex determination (TSD) are especially vulnerable to the effects of a rapidly changing global climate due to their profound sensitivity to thermal cues during development. Predicting the consequences of climate change for these species, including skewed offspring sex ratios, depends on understanding how climatic factors interface with features of maternal nesting behaviour to shape the developmental environment. Here, we measure thermal profiles in 86 nests at two geographically distinct sites in the northern and southern regions of the American alligator's (Alligator mississippiensis) geographical range, and examine the influence of both climatic factors and maternally driven nest characteristics on nest temperature variation. Changes in daily maximum air temperatures drive annual trends in nest temperatures, while variation in individual nest temperatures is also related to local habitat factors and microclimate characteristics. Without any compensatory nesting behaviours, nest temperatures are projected to increase by 1.6-3.7°C by the year 2100, and these changes are predicted to have dramatic consequences for offspring sex ratios. Exact sex ratio outcomes vary widely depending on site and emission scenario as a function of the unique temperature-by-sex reaction norm exhibited by all crocodilians. By revealing the ecological drivers of nest temperature variation in the American alligator, this study provides important insights into the potential consequences of climate change for crocodilian species, many of which are already threatened by extinction.
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Affiliation(s)
- Samantha L Bock
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Savannah River Ecology Laboratory, Aiken, SC 29802, USA
| | - Russell H Lowers
- Integrated Mission Support Services, John F. Kennedy Space Center, FL 32899, USA
| | - Thomas R Rainwater
- Tom Yawkey Wildlife Center, Georgetown, SC 29440, USA.,Belle W. Baruch Institute of Coastal Ecology & Forest Science, Clemson University, Georgetown, SC 29442, USA
| | - Eric Stolen
- Integrated Mission Support Services, John F. Kennedy Space Center, FL 32899, USA
| | - John M Drake
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA 30602, USA
| | | | - Stephanie Weiss
- Integrated Mission Support Services, John F. Kennedy Space Center, FL 32899, USA
| | - Brenton Back
- Integrated Mission Support Services, John F. Kennedy Space Center, FL 32899, USA
| | - Louis Guillette
- Medical University of South Carolina, Hollings Marine Laboratory, Charleston, SC 29412, USA
| | - Benjamin B Parrott
- Odum School of Ecology, University of Georgia, Athens, GA 30602, USA.,Savannah River Ecology Laboratory, Aiken, SC 29802, USA
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Carter AL, Bodensteiner BL, Iverson JB, Milne‐Zelman CL, Mitchell TS, Refsnider JM, Warner DA, Janzen FJ. Breadth of the thermal response captures individual and geographic variation in temperature‐dependent sex determination. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13410] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Anna L. Carter
- Department of Ecology, Evolution & Organismal Biology Iowa State University Ames IA USA
| | | | | | | | - Timothy S. Mitchell
- Department of Ecology, Evolution & Behavior University of Minnesota Minneapolis MN USA
| | | | - Daniel A. Warner
- Department of Biological Sciences Auburn University Auburn AL USA
| | - Fredric J. Janzen
- Department of Ecology, Evolution & Organismal Biology Iowa State University Ames IA USA
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Warner DA, Du WG, Georges A. Introduction to the special issue-Developmental plasticity in reptiles: Physiological mechanisms and ecological consequences. JOURNAL OF EXPERIMENTAL ZOOLOGY PART 2018; 329:153-161. [PMID: 29956505 DOI: 10.1002/jez.2199] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 06/30/2018] [Accepted: 06/04/2018] [Indexed: 12/13/2022]
Abstract
Scientific interest in developmental plasticity spans many disciplines, and research on reptiles has provided many insights into this field. We highlight these contributions, review the field's history, and introduce the special issue on this topic .
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Affiliation(s)
- Daniel A Warner
- Department of Biological Sciences, Auburn University, Auburn, Alabama, USA
| | - Wei-Guo Du
- Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Arthur Georges
- Institute for Applied Ecology, University of Canberra, Canberra, Australia
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