The Great Debate – Mammalian Monogamy

In the case of the evolution of monogamy in primates, evolutionary biologists would contend that its occurrence is beneficial to the fitness of those species, and that the monogamous mating phenotype has been impressed on their genes. For example, the American male prairie vole emits a neurotransmitter during mating that aids in forming bonds with its mate, and also makes the vole exhibit aggressive behavior to other prairie voles besides its mate. The neurotransmitter is made of amino acids coded for by the voles genes (Reece).

In the article Male Infanticide leads to social monogamy in primates, authors Christopher Opie, Quentin D. Atkinson, Robin I. M. Dunbar, and Susanne Shultz find that the evolutionary origin of social monogamy in primates is male infanticide. Through their statistical analysis of primate phylogenies, they claim that “male infanticide precedes the switch to social monogamy.”

In the article The Evolution of Social Monogamy in Mammals by D. Lukas and T.H. Clutton-Brock, the authors say that social monogamy in mammals is derived from ancestral populations where members were solitary and females were intolerant of each other. They discount the infanticide and parental care arguments, and argue that monogamy evolved to reduce competition over males due to the “greater overlap of home ranges between females in solitary species than is socially monogamous ones.”

In terms of data, I feel the article by Christopher Opie has more evidence because of the sheer volume of data points analyzed (10,000 phylogenies), and the quantitative statistical analysis of that data.  The author’s citations seem more professional and credible. In those major respects I feel that this article is more scientific. The visual representations incorporating the statistical percentages were a little hard for me to follow, though.

There was not as much data incorporated into D. Lukas’s article as Cristopher Opie’s, but I found that when it was, the clear-cut percentages were easier to understand. The visual aids (graph and mammalian monogamy flowchart) helped a lot in my understanding.

These two articles have helped me better understand the various hypotheses in the scientific community about the evolution of monogamy in primates, but the small holes in their arguments leave me wondering. The first article admits that if infanticide did in fact precede monogamy, more mammalian species should be monogamous, and the authors attribute that to specific “ecological conditions”. The second article presents evidence in direct opposition of the first article, but their data does not conclusively support their own opinions.

Reece, Jane B., and Neil A. Campbell. “Chapter 51: Behavioral Ecology.” Campbell

       Biology / Jane B. Reece … Boston: Benjamin Cummings, 2011. N. pag. Print.

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