This study looked at the diversity of MHC-based constitution n a wild population of grey mouse lemurs. Grey mouse lemurs are highly promiscuous, which is perhaps expected given that they are only receptive for one night per year. Behavioral studies show that females mate indiscriminately during this night, implying that there is no evidence of pre-copulatory mate choice. However, the authors expected that female post-copulatory mating choices should be based on the disassortative or diverse MHC hypotheses.
They found that fathers of offspring had a higher number of MHC supertypes different from the mother than the females’ other partners that did note sire offspring, indicating that a post-copulatory mechanism could take place based on preference for MHC dissimilarity, and thus more beneficial immunocompetence, in offspring. The study supports the hypotheses of MHC-associated post-copulatory mate choice in wild lemurs, with sperm competition and female cryptic choice highlighted as the primary mechanisms for increased diversity in immune genes.