Are intelligent people less promiscuous?

Half Sigma claims that there is a negative correlation between intelligence and sexual activity. He says that highly intelligent people are less likely to have sex and have fewer sex partners. This may help to explain why IQ's are so low in sub-Saharan Africa. In many parts of Africa, diseases such as malaria are rampant and death rates - particularly amongst infants and children - are very high. In order for their genes to have any chance of survival in the long term black Africans have to produce as many children as possible in the hopes that some of them will survive long enough to have children of their own. Since, according to Half Sigma, less intelligent people are more promiscuous this would mean that less intelligent Africans would have a reproductive advantage over more intelligent ones.