Details

Autor(en) / Beteiligte

• Veran, Sophie
• Beissinger, Steven R

Titel

Demographic origins of skewed operational and adult sex ratios: perturbation analyses of two-sex models

Ist Teil von

• Ecology letters, 2009-02, Vol.12 (2), p.129-143

Ort / Verlag

Oxford, UK: Oxford, UK : Blackwell Publishing Ltd

Erscheinungsjahr

2009

Quelle

MEDLINE

Beschreibungen/Notizen

• Skewed sex ratios - operational (OSR) and Adult (ASR) - arise from sexual differences in reproductive behaviours and adult survival rates due to the cost of reproduction. However, skewed sex-ratio at birth, sex-biased dispersal and immigration, and sexual differences in juvenile mortality may also contribute. We present a framework to decompose the roles of demographic traits on sex ratios using perturbation analyses of two-sex matrix population models. Metrics of sensitivity are derived from analyses of sensitivity, elasticity, life-table response experiments and life stage simulation analyses, and applied to the stable stage distribution instead of lambda. We use these approaches to examine causes of male-biased sex ratios in two populations of green-rumped parrotlets (Forpus passerinus) in Venezuela. Female local juvenile survival contributed the most to the unbalanced OSR and ASR due to a female-biased dispersal rate, suggesting sexual differences in philopatry can influence sex ratios more strongly than the cost of reproduction.