Men's cichlid fish sometimes fertilize eggs in the nests belonging to one of their male relatives, behaving intuitively, but ultimately beneficial, according to a study published BMC Biology.
Karl-Franzens-Universität Graz, Austria, investigated behavior known as cuckoldy cichlid in fish, where "cuckolder" men mate with women who are already social partners with other men. As a result, men are not always genetic fathers of female partners. It is believed to be a matter for the mother's social partner, especially if she then cares for offspring not all of her own. Researchers found that "cuckolder male" and maternal social partner were on average more likely to be unexpected than expected.
Dr Kristina Sefc, author of the study, said: "We found that partner male fish were often associated with some men who were robbing some egg fertilizer. If men are involved, we usually expect them to compete less with the other, but no more. This is the point of a clash between related men, however, when spawning events are associated with many men, including many unrelated fathers, basically working together to compete with the number of unrelated men. "
Researchers concluded that admitting cuckoldry relative may sometimes make sense, because when men are connected, they have a part of their genes, and these genes have the ability to get to the offspring, regardless of which man is fertilizing. Importantly, this additional imprisonment of relatives can also reduce the number of offspring, other males, involved in the spawning event. After all, both the original man and his related imprisonment can benefit.
Aneesh Bose, co-author of the study, said: "This study may change our contemporary view of cuckoldry and paternity losses. for zero, here we show that men can be related to their cuckolders, and it will be exciting to see how widespread this phenomenon is in other species.
The researchers combined theoretical modeling with a detailed genetic study of socially monogamous cichlid fish. Variabilichromis moorii– a species where both men and women are caring for parents. They checked how closely related male fish were with their cuckolders, in addition to other couples, including women with cuckolders, and male and female social partners. The authors read the offspring of 70 varieties and were able to reconstruct 74 penile genotypes.
The authors warn that the empirical part of this study was done with one fish species; therefore further research is needed to determine whether the findings can be applied more widely.
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Aneesh P.H. Bose et al., Inclusive Fitness Benefits Reduce Prisoners' Costs for Social Pairs for Men BMC Biology (2019). DOI: 10.1186 / s12915-018-0620-6