When investment backfires: Unbalanced sex ratios and mental health among boys in rural areas

Parental investment, sexual selection and sex ratios.

Conventional sex roles imply caring females and competitive males. The evolution of sex role divergence is widely attributed to anisogamy initiating a self-reinforcing process. The initial asymmetry in pre-mating parental investment (eggs vs. sperm) is assumed to promote even greater divergence in post-mating parental investment (parental care). But do we really understand the process? Trivers ...

Journal of Rural Mental Health Suicide in Rural Areas: An Updated Review of the Literature

Sex investment ratios in eusocial Hymenoptera support inclusive fitness theory.

Inclusive fitness theory predicts that sex investment ratios in eusocial Hymenoptera are a function of the relatedness asymmetry (relative relatedness to females and males) of the individuals controlling sex allocation. In monogynous ants (with one queen per colony), assuming worker control, the theory therefore predicts female-biased sex investment ratios, as found in natural populations. Rece...

Sex ratio dependent dispersal when sex ratios vary between patches.

Female biased sex ratios reduce competition between brothers when mating takes place within local patches. Male dispersal prior to mating is another strategy that reduces competition between brothers. One may thus expect these two traits to co-evolve and this is partially met in that sex ratios becomes less female biased as dispersal increases. However, the evolutionary stable degree of dispers...

Comparison of quality of life and mental health among elderly people in rural and suburban areas, Thailand.

This community based cross-sectional study design assessed the quality of life, mental and physical health among people aged > or = 60 years living in rural and suburban areas of northern Thailand. A cluster random sampling technique was used. The instruments used to assess quality of life were the Thai General Health Questionnaire (Thai-28), the WHO Quality of Life Assessment in Thai (WHOQOL-B...