eCite Digital Repository

Extreme sex ratio variation in relation to change in condition around conception


Cameron, EZ and Linklater, WL, Extreme sex ratio variation in relation to change in condition around conception, Biology Letters, 3, (4) pp. 395-397. ISSN 1744-9561 (2007) [Refereed Article]

Restricted - Request a copy

Copyright Statement

Copyright 2007 Royal Society Publishig

Official URL:

DOI: doi:10.1098/rsbl.2007.0089


Adaptive theory predicts that mothers would be advantaged by adjusting the sex ratio of their offspring in relation to their offspring's future reproductive success. Studies investigating sex ratio variation in mammals have produced notoriously inconsistent results, although recent studies suggest more consistency if sex ratio variation is related to maternal condition at conception, potentially mediated by changes in circulating glucose level. Consequently, we hypothesized that change in condition might better predict sex ratio variation than condition per se. Here, we investigate sex ratio variation in feral horses (Equus caballus), where sex ratio variation was previously shown to be related to maternal condition at conception. We used condition measures before and after conception to measure the change in condition around conception in individual mothers. The relationship with sex ratio was substantially more extreme than previously reported: 3% of females losing condition gave birth to a son, whereas 80% of those females that were gaining condition gave birth to a son. Change in condition is more predictive of sex ratio than actual condition, supporting previous studies, and shows the most extreme variation in mammals ever reported.

Item Details

Item Type:Refereed Article
Keywords:evolutionary theory, sex allocation, sex ratios, maternal investment
Research Division:Biological Sciences
Research Group:Ecology
Research Field:Behavioural ecology
Objective Division:Environmental Management
Objective Group:Terrestrial systems and management
Objective Field:Terrestrial biodiversity
UTAS Author:Cameron, EZ (Professor Elissa Cameron)
ID Code:67399
Year Published:2007
Web of Science® Times Cited:67
Deposited By:Zoology
Deposited On:2011-03-03
Last Modified:2011-03-24

Repository Staff Only: item control page