Journal
AMERICAN NATURALIST
Volume 170, Issue 5, Pages E112-E128Publisher
UNIV CHICAGO PRESS
DOI: 10.1086/522057
Keywords
kin selection; local resource competition; mathematical; model; sex allocation; sex ratio; Trivers-Willard effect
Categories
Funding
- Natural Environment Research Council [NER/A/S/2002/00808] Funding Source: researchfish
Ask authors/readers for more resources
Tests of sex allocation theory in vertebrates are usually based on verbal arguments. However, the operation of multiple selective forces can complicate verbal arguments, possibly making them misleading. We construct an inclusive fitness model for the evolution of condition-dependent brood sex ratio adjustment in response to two leading explanations for sex ratio evolution in vertebrates: the effect of maternal quality on the fitness of male and female offspring ( the Trivers-Willard hypothesis [TWH]) and local resource competition (LRC) between females. We show ( 1) the population sex ratio can be either unbiased or biased in either direction ( toward either males or females); ( 2) brood sex ratio adjustment can be biased in either direction, with high-quality females biasing reproductive investment toward production of sons ( as predicted by the TWH) or production of daughters ( opposite to predictions of the TWH); and ( 3) selection can favor gradual sex ratio adjustment, with both sons and daughters being produced by both high- and low-quality mothers. Despite these complications, clear a priori predictions can be made for how the population sex ratio and the conditional sex ratio adjustment of broods should vary across populations or species, and within populations, across individuals of different quality.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available