Podocnemis expansa Turtles Hint to a Unifying Explanation for the Evolution of Temperature-Dependent Sex Determination in Long-Lived and Short-Lived Vertebrates
Date
2021
Authors
Major Professor
Advisor
Committee Member
Journal Title
Journal ISSN
Volume Title
Publisher
© 2021 S. Karger AG, Basel
Authors
Person
Valenzuela, Nicole
Professor
Research Projects
Organizational Units
Organizational Unit
Ecology, Evolution and Organismal Biology
The Department of Ecology, Evolution, and Organismal Biology seeks to teach the studies of ecology (organisms and their environment), evolutionary theory (the origin and interrelationships of organisms), and organismal biology (the structure, function, and biodiversity of organisms). In doing this, it offers several majors which are codirected with other departments, including biology, genetics, and environmental sciences.
History
The Department of Ecology, Evolution, and Organismal Biology was founded in 2003 as a merger of the Department of Botany, the Department of Microbiology, and the Department of Zoology and Genetics.
Dates of Existence
2003–present
Related Units
- College of Agriculture and Life Sciences (parent college)
- College of Liberal Arts and Sciences (parent college)
- Department of Botany (predecessor, 2003)
- Department of Microbiology (predecessor, 2003)
- Department of Zoology and Genetics (predecessor, 2003)
Journal Issue
Is Version Of
Versions
Series
Department
Ecology, Evolution and Organismal Biology
Abstract
The adaptive significance of temperature-dependent sex determination (TSD) remains elusive for many long-lived reptiles. Various hypotheses proposed potential ecological drivers of TSD. The Charnov-Bull’77 model remains the most robust, and explains the maintenance of TSD in short-lived vertebrates, where sex ratios correlate with seasonal temperatures within years that confer sex-specific fitness (colder springs produce females who grow larger and gain in fecundity, whereas warmer summers produce males who mature at smaller size). Yet, evidence of fitness differentials correlated with incubation temperature is scarce for long-lived taxa. Here I propose that the Charnov-Bull’77 model applies similarly to short-lived taxa, but at a longer temporal scale, by revisiting ecological and genetic data from the long-lived turtle Podocnemis expansa. After ruling out multiple alternatives, I hypothesize that warmer-drier years overproduce females and correlate with optimal resource availability in the flood plains, benefitting daughters more than sons, whereas resources are scarcer during colder-rainier years (due to reduced flowering/fruiting) that overproduce males, whose fitness is less impacted by slower growth rates. New technical advances and collaborative interdisciplinary efforts are delineated that should facilitate testing this hypothesis directly, illuminating our understanding of TSD evolution in P. expansa and other long-lived TSD reptiles.
Comments
This is a manuscript of an article published as Valenzuela, Nicole. "Podocnemis expansa Turtles Hint to a Unifying Explanation for the Evolution of Temperature-Dependent Sex Determination in Long-Lived and Short-Lived Vertebrates." Sexual Development 15 (2021): 23-37. doi:10.1159/000515208. Posted with permission.