The Biology of Monogamy & Polygamy Aaron Warren

Monogamy (dedicated and loyal to one mate in a relationship either “for life” or just during that mating season) Marmoset, beaver, swan, eagle, >90% of birds monogamous

Polygamy (promiscuous, has many mates, is a “player”, unfaithful) Some baboons, wrens, pheasants, marmots, elk, >90% mammals polygamous

Evolutionary Advantages Female mates with many males, Male cares for children Polygyny Monogamy Polyandry Male mates with many females, Female cares for children

Is it Nature (your biology) or Nurture (how you were raised)? Do you think humans are more monogamous or polygamous? What factors affect whether someone is more monogamous or polygamous (explain)? How do feelings of "love" relate to monogamy and polygamy?

Vole Mating Montane and Meadow voles (polygamous) https://www.youtube.com/watch?v=pA4w--HP7tc Montane and Meadow voles (polygamous) Prairie vole (monogamous) Spends more time with mate Mate guarding (attacks strange males) Child rearing (shared parenting responsibilities)

Meadow voles Use virus to over- express vasopressin receptor Polygamous vole becomes more monogamous (spends more time with mate compared to stranger) Polygamous, v1 receptor added to VP, becomes more monogamous https://www.youtube.com/watch?v=pA4w--HP7tc

Vasopressin released from hypothalamus while mating, which leads to mate guarding & child rearing behaviors Experiment 1: Vasopressin receptor blockers in monogamous male voles Inhibits guarding behavior Experiment 2:Vasopressin infusion into virgin males Promotes mate guarding & child rearing behaviors Blockers inhibit mate protection (jealous husbandry), infusion promotes monogamy and child rearing

So far, we’ve seen evidence that mating behavior is due to “nature” (your biology) Come up with an experiment that would test whether or not the voles are monogamous/polygamous because of “nurture” (how you’re raised)

What about in humans? https://www.newscientist.com/article/dn14641- monogamy-gene-found-in-people/#.VTAvqfnF-Sr https://www.newscientist.com/article/dn14641-monogamy-gene-found-in-people/#.VTAvqfnF-Sr

Results of the Sweden study: Effects of having 2 mutated alleles for this gene: Significantly lower score on “Partner Bonding Scale” Twice as likely to have problems with your marriage Half as likely to be married if in a relationship

How does it make you feel to know that feelings of “love” and bonding can be influenced by your genes? How does this affect your view on relationships? Would you want to know whether your girl/boyfriend has the mutated version of the oxytocin receptor gene? Would you want to know if you had the mutation or not? What are the pro's and con's of having the technology (like in GATTACA) for people to easily see which genes you have? What new thoughts or questions do you have now?

Citations Donaldson, Z., Young, L. (2008). Oxytocin, Vasopressin, and the Neurogenetics of Sociality. Science. 322(5903): 900- 904 Fackelmann, K. (1993). Hormone of monogamy: the prairie vole and the biology of mating. Science News. Geller, B. (2004). The Monogamy Gene? An Animal Study. Journal Watch Psychiatry