Mutual information reveals variation in temperature-dependent sex determination in response to environmental fluctuation, lifespan and selection

Lisa Schwanz, Stephen Proulx

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Quantifying the degree to which sex determination depends on the environment can yield insight into the evolution, ecological dynamics, and functional aspects of sex determination. In temperature-dependent sex determination (TSD), theory often predicts a complete dependence of sex on temperature, with a switch-like reaction norm. However, empirical data suggest more shallow relationships between sex and temperature. Here, we demonstrate the usefulness of an index, mutual information (MI), to reflect the degree of temperature dependence in sex. MI depends on both the shape of a reaction norm and the natural temperature variation, thus providing ameasure of TSD that is ecologically dependent.We demonstrate that increased lifespan and decreased environmental fluctuation predict reaction norms with high MI (switchlike). However, mutation and weaker selection on sex-specific performance reduce average MI in a population, suggesting that mutation-selection balance can resolve some of the conflict between theoretical predictions of individual-based optimality and population-based empirical results. The MI index allows clear comparison of TSD across life histories and habitats and reveals functional similarities between reaction norms that may appear different. The model provides testable predictions for TSD across populations, namely that MI should increase with lifespan and decrease with historical environmental fluctuations.
Original languageEnglish
Pages (from-to)2441-2448
Number of pages8
JournalRoyal Society of London. Proceedings B. Biological Sciences
Volume275
DOIs
Publication statusPublished - 2008
Externally publishedYes

Fingerprint

sex determination
reaction norm
Temperature
gender
temperature
mutation
Sex Preselection
Population
Mutation
prediction
life history
Ecosystem
Switches
habitat

Cite this

@article{bae839c2a8064f40b15ba7209cfdb823,
title = "Mutual information reveals variation in temperature-dependent sex determination in response to environmental fluctuation, lifespan and selection",
abstract = "Quantifying the degree to which sex determination depends on the environment can yield insight into the evolution, ecological dynamics, and functional aspects of sex determination. In temperature-dependent sex determination (TSD), theory often predicts a complete dependence of sex on temperature, with a switch-like reaction norm. However, empirical data suggest more shallow relationships between sex and temperature. Here, we demonstrate the usefulness of an index, mutual information (MI), to reflect the degree of temperature dependence in sex. MI depends on both the shape of a reaction norm and the natural temperature variation, thus providing ameasure of TSD that is ecologically dependent.We demonstrate that increased lifespan and decreased environmental fluctuation predict reaction norms with high MI (switchlike). However, mutation and weaker selection on sex-specific performance reduce average MI in a population, suggesting that mutation-selection balance can resolve some of the conflict between theoretical predictions of individual-based optimality and population-based empirical results. The MI index allows clear comparison of TSD across life histories and habitats and reveals functional similarities between reaction norms that may appear different. The model provides testable predictions for TSD across populations, namely that MI should increase with lifespan and decrease with historical environmental fluctuations.",
keywords = "Charnov-Bull, information theory, mutation-selection balance, mutational load, sex allocation.",
author = "Lisa Schwanz and Stephen Proulx",
year = "2008",
doi = "10.1098/rspb.2008.0427",
language = "English",
volume = "275",
pages = "2441--2448",
journal = "Royal Society of London. Proceedings B. Biological Sciences",
issn = "0962-8452",
publisher = "Royal Society of London",

}

TY - JOUR

T1 - Mutual information reveals variation in temperature-dependent sex determination in response to environmental fluctuation, lifespan and selection

AU - Schwanz, Lisa

AU - Proulx, Stephen

PY - 2008

Y1 - 2008

N2 - Quantifying the degree to which sex determination depends on the environment can yield insight into the evolution, ecological dynamics, and functional aspects of sex determination. In temperature-dependent sex determination (TSD), theory often predicts a complete dependence of sex on temperature, with a switch-like reaction norm. However, empirical data suggest more shallow relationships between sex and temperature. Here, we demonstrate the usefulness of an index, mutual information (MI), to reflect the degree of temperature dependence in sex. MI depends on both the shape of a reaction norm and the natural temperature variation, thus providing ameasure of TSD that is ecologically dependent.We demonstrate that increased lifespan and decreased environmental fluctuation predict reaction norms with high MI (switchlike). However, mutation and weaker selection on sex-specific performance reduce average MI in a population, suggesting that mutation-selection balance can resolve some of the conflict between theoretical predictions of individual-based optimality and population-based empirical results. The MI index allows clear comparison of TSD across life histories and habitats and reveals functional similarities between reaction norms that may appear different. The model provides testable predictions for TSD across populations, namely that MI should increase with lifespan and decrease with historical environmental fluctuations.

AB - Quantifying the degree to which sex determination depends on the environment can yield insight into the evolution, ecological dynamics, and functional aspects of sex determination. In temperature-dependent sex determination (TSD), theory often predicts a complete dependence of sex on temperature, with a switch-like reaction norm. However, empirical data suggest more shallow relationships between sex and temperature. Here, we demonstrate the usefulness of an index, mutual information (MI), to reflect the degree of temperature dependence in sex. MI depends on both the shape of a reaction norm and the natural temperature variation, thus providing ameasure of TSD that is ecologically dependent.We demonstrate that increased lifespan and decreased environmental fluctuation predict reaction norms with high MI (switchlike). However, mutation and weaker selection on sex-specific performance reduce average MI in a population, suggesting that mutation-selection balance can resolve some of the conflict between theoretical predictions of individual-based optimality and population-based empirical results. The MI index allows clear comparison of TSD across life histories and habitats and reveals functional similarities between reaction norms that may appear different. The model provides testable predictions for TSD across populations, namely that MI should increase with lifespan and decrease with historical environmental fluctuations.

KW - Charnov-Bull

KW - information theory

KW - mutation-selection balance

KW - mutational load

KW - sex allocation.

U2 - 10.1098/rspb.2008.0427

DO - 10.1098/rspb.2008.0427

M3 - Article

VL - 275

SP - 2441

EP - 2448

JO - Royal Society of London. Proceedings B. Biological Sciences

JF - Royal Society of London. Proceedings B. Biological Sciences

SN - 0962-8452

ER -