Limits...
Female philopatry in a heterogeneous environment: ordinary conditions leading to extraordinary ESS sex ratios.

Hulin V, Guillon JM - BMC Evol. Biol. (2007)

Bottom Line: The selection forces responsible for these results are fully described.This study provides a new perspective on the evolutionary significance of temperature sex determination.We discuss the case of turtles by comparing our theoretical results with field observations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Univ Paris-Sud, CNRS, AgroParisTech, Laboratoire Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 362, Orsay, F-91405, France. vincent.hulin@u-psud.fr

ABSTRACT

Background: We use a simulation-based model to study the impact of female philopatry and heterogeneity of habitat quality on the evolution of primary sex ratio.

Results: We show that these conditions may lead to strongly biased ESS habitat-dependent sex ratios, under two kinds of density-dependent population regulation. ESS sex ratios are always biased towards females in good habitats, towards males in poor habitats, and are generally equilibrated considering the whole population. Noticeably, the predicted bias of sex ratio usually increases with decreasing female philopatry.

Conclusion: The selection forces responsible for these results are fully described. This study provides a new perspective on the evolutionary significance of temperature sex determination. We discuss the case of turtles by comparing our theoretical results with field observations.

Show MeSH
ESS sex ratios in GOOD habitats (G), POOR habitats (P) and in the whole population (SRtot) as a function of female dispersal rate (df) in the model with habitat density-dependent regulation. (a): g = 0.3. (b): g = 0.7. Bars show maximal and minimal values in 20,000 generations at the equilibrium. Triangles: G, squares: P and circles: SRtot. Plain symbols: F = 1.5, open symbols: F = 2. Results are shown for simulations run with initial allele values of G1,G2,P1 and P2 = 0.5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC1804258&req=5

Figure 2: ESS sex ratios in GOOD habitats (G), POOR habitats (P) and in the whole population (SRtot) as a function of female dispersal rate (df) in the model with habitat density-dependent regulation. (a): g = 0.3. (b): g = 0.7. Bars show maximal and minimal values in 20,000 generations at the equilibrium. Triangles: G, squares: P and circles: SRtot. Plain symbols: F = 1.5, open symbols: F = 2. Results are shown for simulations run with initial allele values of G1,G2,P1 and P2 = 0.5.

Mentions: We apply one of two different kinds of density-dependent regulation. The first one (called HABITAT) occurs in each habitat and corresponds to a regulation at the scale of the nesting beach: 5,000 individuals will grow to adulthood, a proportion Fg/(Fg+1-g) born in GOOD habitats and a proportion (1-g)/(Fg+1-g) born in POOR habitats. The second one (called TOTAL) consists in the random draw of 5,000 individuals in the entire population of offspring, which will grow into adulthood. Then, in the adult population, the proportions of individuals born in GOOD habitats and in POOR habitats are respectively FNg/(FNg+Np) and Np/(FNg+ Np), with Np and Ng the numbers of females nesting in POOR and GOOD habitats. This corresponds to a regulation at the scale of the entire population, on feeding grounds for example.


Female philopatry in a heterogeneous environment: ordinary conditions leading to extraordinary ESS sex ratios.

Hulin V, Guillon JM - BMC Evol. Biol. (2007)

ESS sex ratios in GOOD habitats (G), POOR habitats (P) and in the whole population (SRtot) as a function of female dispersal rate (df) in the model with habitat density-dependent regulation. (a): g = 0.3. (b): g = 0.7. Bars show maximal and minimal values in 20,000 generations at the equilibrium. Triangles: G, squares: P and circles: SRtot. Plain symbols: F = 1.5, open symbols: F = 2. Results are shown for simulations run with initial allele values of G1,G2,P1 and P2 = 0.5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC1804258&req=5

Figure 2: ESS sex ratios in GOOD habitats (G), POOR habitats (P) and in the whole population (SRtot) as a function of female dispersal rate (df) in the model with habitat density-dependent regulation. (a): g = 0.3. (b): g = 0.7. Bars show maximal and minimal values in 20,000 generations at the equilibrium. Triangles: G, squares: P and circles: SRtot. Plain symbols: F = 1.5, open symbols: F = 2. Results are shown for simulations run with initial allele values of G1,G2,P1 and P2 = 0.5.
Mentions: We apply one of two different kinds of density-dependent regulation. The first one (called HABITAT) occurs in each habitat and corresponds to a regulation at the scale of the nesting beach: 5,000 individuals will grow to adulthood, a proportion Fg/(Fg+1-g) born in GOOD habitats and a proportion (1-g)/(Fg+1-g) born in POOR habitats. The second one (called TOTAL) consists in the random draw of 5,000 individuals in the entire population of offspring, which will grow into adulthood. Then, in the adult population, the proportions of individuals born in GOOD habitats and in POOR habitats are respectively FNg/(FNg+Np) and Np/(FNg+ Np), with Np and Ng the numbers of females nesting in POOR and GOOD habitats. This corresponds to a regulation at the scale of the entire population, on feeding grounds for example.

Bottom Line: The selection forces responsible for these results are fully described.This study provides a new perspective on the evolutionary significance of temperature sex determination.We discuss the case of turtles by comparing our theoretical results with field observations.

View Article: PubMed Central - HTML - PubMed

Affiliation: Univ Paris-Sud, CNRS, AgroParisTech, Laboratoire Ecologie, Systématique et Evolution, UMR 8079, Bâtiment 362, Orsay, F-91405, France. vincent.hulin@u-psud.fr

ABSTRACT

Background: We use a simulation-based model to study the impact of female philopatry and heterogeneity of habitat quality on the evolution of primary sex ratio.

Results: We show that these conditions may lead to strongly biased ESS habitat-dependent sex ratios, under two kinds of density-dependent population regulation. ESS sex ratios are always biased towards females in good habitats, towards males in poor habitats, and are generally equilibrated considering the whole population. Noticeably, the predicted bias of sex ratio usually increases with decreasing female philopatry.

Conclusion: The selection forces responsible for these results are fully described. This study provides a new perspective on the evolutionary significance of temperature sex determination. We discuss the case of turtles by comparing our theoretical results with field observations.

Show MeSH