Differential Parental Investment In Sons And Daughters In Malawi

Many evolutionary theories have explained differential parental investment in sons and daughters. The applicability of the theories varies from population to population. This study aimed at finding out the most appropriate evolutionary differential parental investment theory applicable to Malawi between the Trivers-Willard Hypothesis (TWH) and the Local Resource Hypothesis (LRH) by testing two predictions related to both hypotheses. The predictions were about sex ratio and parental investment.Both quantitative and qualitative data was used in the study. A sample of 870 household heads was used to collect quantitative data. The qualitative data was collected from 10 key informants who were purposively selected from the 870 household heads.Both predictions related to TWH were not supported by the data. The offspring’ sex ratios by parents’ social status groups were not significantly different,F(9,2102)=1.37, P= 0.20, Wilks’Λ= 0.99, ηp2= 0.005. On the other hand, parental investment in sons’and daughters’ education differed significantly F(9,1090)= 3.615, P= 0.0001, Wilks’Λ= 0.93, ηp2 = 0.024 but the interaction effects observed were not as predicted by TWH. However, both predictions related to LRH were supported by the data. Parents were found to overproduce the less costly sex of offspring t869= 3.050, p= 0.002,95% CI, r= 0.1. Sons were hypothesized as the less costly sex of offspring based on the assessment of sex resource demands. Likewise, parents were found to invest more in less costly sons’than daughters’ education t472=8.03, p= 0.0001,95% CI, r= 0.47.Based on these findings, the TWH could not appropriately explain the evolutionary differential parental investment in sons and daughters than the LRH could in case of Malawi, particularly among the Ngoni of Ntcheu District. This gives evidence that natural selection could select for a particular sex of offspring based on its behavior as influenced by culture. In case of the Ngoni social group in Malawi, parental bias towards sons seemingly result from the way sons behave by reducing their resource demands as a result of culture that makes them less costly sex of offspring. Hence social policy planners need to take an appropriate action to address the cultural related gender bias to avoid continuation of an underclass of women without appropriate education for that could be detrimental to the nation’s socio-economic development.