The development of paternal care

Although increasing in popularity, relatively few studies have investigated the how paternal care behaviour develops and is expressed, and what role fathers play in these processes.Bester-Meredith &Marler (2003) showed that a decrease in paternal care behaviour by California mouse Peromyscus californicus results in sons also showing lower levels of care, possibly because vasopressin expression in the bed nucleus of the stria terminalis (BNST) facilitates this behaviour. However, Bredy et al. (2004) found no apparent influence of paternal care on the development of the hippocampus, the area of the brain that secretes vasopressin.

Behaviour, in general, is influenced genetically and non-genetically (e.g. learning, Cushing & Kramer 2005), although behavioural expression can be more strongly influenced either by environmental or genetic components. For example, offspring feeding rate in long-tailed tits Aegithalos caudatus (Fig. 1) has a significant heritable component (MacColl & Hatchwell 2003), whereas paternal state is strongly regulated by environmental cues in meadow voles Microtus pennsylvanicus (Fig. 2), a species that is rarely paternal (Parker& Lee 2001). However, few studies have looked at the relative influence of both genetic and non-genetic factors on the development of paternal care.

 

Fig. 1 Long-tailed tit Aegithalos caudatus
(Tim Edelsten: picture accessed 28 July 2014; 12h53)
(http://www.birdskorea.org/Birds/Birdnews/BK-BN-Review-2007.shtml)

Fig. 2 Juvenile meadow vole Microtus pennsylvanicus
(Unknown: picture accessed 28 July 2014; 12h59)
(http://natchem.wordpress.com/2010/06/04/the-genetics-of-monogamy-guys-girls-you-better-read-this/)




In two recent studies, Prof. Neville Pillay (University of the Witwatersrand) and I demonstrated the importance of both non-genetic (Rymer & Pillay 2011a) and genetic (Rymer & Pillay 2011b) factors on the developmental of paternal care behaviour in biparental African striped mice Rhabdomys pumilio (Fig. 3). We found that mothers are particularly important for the development of paternal care behaviour in their sons (Rymer & Pillay 2011a). Sons raised by their mothers only show heightened levels of paternal care as adults, as mothers compensate for the absence of the father by increasing the amount of maternal care invested in their sons (Rymer & Pillay 2011a). Interestingly, there appears to be little genetic heritability of paternal care either down the matriline or the patriline (Rymer & Pillay 2011b), suggesting that the development of paternal care in striped mice in strongly regulated by environmental factors.

Fig. 3 Juvenile striped mice Rhabdomys pumilio

(Gaby Schmohl: picture accessed 28 July 2014; 16h10)
(http://www.stripedmouse.com/site1_3.htm)


In my next blog, I’ll make a start on those factors influencing the expression of paternal care.