sharing of parental roles and egalitarian nest building in couples

[GoodTaste]

Prairie voles (Microtus ochrogaster) have long been of interest to neuroscientists and endocrinologists who study the social behaviour of animals, in part because this species forms monogamous pair bonds, essentially mating for life. The voles' pair bonding, sharing of parental roles and egalitarian nest building in couples makes them a good model for understanding the biology of monogamy and mating in humans.

Source: Nature Gene switches make prairie voles fall in love

I don't clearly understand "sharing of parental roles and egalitarian nest building in couples". Is the grammatical structure "sharing of parental roles and (sharing of ) egalitarian nest building in couples"? Does "in couples" mean "together with both the 'busband' and the 'wife' "?

 

[Barque]

Is the grammatical structure "sharing of parental roles and (sharing of ) egalitarian nest building in couples"?

The sentence refers to three characteristics of voles (note the possessive apostrophe in voles').
1. Pair bonding,
2. Sharing of parental roles (between the male and female partners), and
3. Egalitarian nest building [that is seen] in couples.

and (sharing of ) egalitarian nest building in couples"?

"Egalitarian" here means that they both take responsibility for nest building. "Sharing of egalitarian nest building" would be redundant and wrong.

Does "in couples" mean "together with both the 'busband' and the 'wife' "?

It refers to a male and a female who have mated.

makes them

This should be "make" (the plural form of the verb) as it refers to multiple characteristics.