Mating Behaviour- Faithful, maybe not.

In the context of a committed relationship, we would always expect our partner to remain faithful, loving, monogamous. Both physically and emotionally, we don’t stray.

Unsurprisingly, some animals mating behaviour are similar to us. Such ‘expectations’ has its roots in social organization and brain chemicals (neurotransmitters).  

The mating behaviour of different species of voles differ. Microtus pennsylvanicus, the Meadow Vole, is promiscuous. Mature male and female voles do not cohabit; there is a lack of paternal care, and even the pups’ mother spend much time outside the nest, displaying relatively lesser maternal warmth and care. Females keep males out of the nest, to the extent of being a “self-sufficient” unit with her young. In stark contrast, Microtus ochrogaster, the Prairie Vole has a permanent male-female bond, with mates nesting together and showering both maternal and paternal care on their young. They are protective of their offspring and have a stable family unit. Male prairie voles are monogamous and able to successfully resist new mates. These differences in mating behaviour and social organization led to differential parenting behaviours, with the meadow voles’ young developing at a faster rate hence requiring less care from their mother.

Biochemistry offers an interesting perspective explaining for the monogamous behaviour of prairie voles. Oxytocin is an important contributing chemical. According to Williams and colleagues (1994), Microtus ochrogaster receiving oxytocin led to the formation of partner preference after cohabitation. In the video below, Microtus pennsylvanicus, with insufficient receptors for oxytocin and hence behaved promiscuously became monogamous upon experimental manipulation that increased its oxytocin receptors. This shows that oxytocin influences the mating behaviour of voles.

Oxytocin is important in humans too! It helps to increase mother-infant bonding, interpersonal trust, and is released during sex. Perhaps, it can help us to have a monogamous relationship as well.

(298 words)

References:

” ‘Fidelity gene’ found in voles,” by Julianna Kettlewell. BBC News, 16 June 2004. URL: http://news.bbc.co.uk/2/hi/science/nature/3812483.stm (accessed on 24 March 2013).

McGuire, B. & M. Novak, 1984. A Comparison Of Maternal Behaviour in the Meadow Vole (Microtus pennsylvanicus), Prairie Vole (M. ochrogaster) and Pine Vole (M. pinetorum). Animal Behaviour, 32(4): 1132-1141.

Oxytocin – “Prairie Vole Experiment,” by DeliciouslyDevious Youtube Channel, 8 January 2012. URL: http://www.youtube.com/watch?v=pA4w–HP7tc (accessed on 23 March 2013).

Williams, J. R., T. R. Insel, C. R. Harbaught & C. S. Carter, 1994. Oxytocin Administered Centrally Facilitates Formation of a Partner preference in Female Prairie Voles (Microtus ochrogaster). Journal of Neuroendocrinology, 6: 247-250.