Unbiased Sex Ratios Among the Bari: An Evolutionary Interpretation
We examine whether among the Bari sex ratios at birth or later ages deviate from the value of one expected by chance. We find no significant bias toward sons or daughters. We also examine whether the costs and benefits associated with sons and daughters are similar or if one sex is more expensive than the other. We contrast our results with predictions derived from Fisher's and the Trivers-Willard hypotheses on sex ratios.
This article is the second of two parts. The first one was published in the issue no 2 of this same journal. The preseni study uses the dependency index and the youth ratio to describe the aging process both at regional and municipal levels. Our data show a yet moderate aging process in (he region. with an uneven distribution throughout the different municipalities.