University of East Anglia - Survival of the promiscuous

Female birds may increase their offspring's chances of survival by being unfaithful to their partners, a study suggests. In many species, females pair up with specific mates who helps raise their offspring, but academics at the University of East Anglia used DNA studies across a wide range of animals, including birds, to show that offspring are often sired by fathers other than the pair male. The study shows that these extra-pair fertilisations can result in a higher diversity of genes that detect disease and trigger immune responses. As a consequence, the offspring survive longer.