Pair Bond - Examples

Examples

When discussing the social life of the bank swallow, Lipton and Barash state:

For about four days immediately prior to egg-laying, when copulations lead to fertilizations, the male bank swallow is very busy, attentively guarding his female. Before this time, as well as after—that is, when her eggs are not ripe, and again after his genes are safely tucked away inside the shells—he goes seeking extra-pair copulations with the mates of other males…who, of course, are busy with defensive mate-guarding of their own.

In various species, males provide parental care and females mate with multiple males. For example, recent studies show that extra-pair copulation frequently occurs in monogamous birds in which a "social" father provides intensive care for its "social" offspring.

A University of Florida scientist reports that male sand gobies work harder at building nests and taking care of eggs when females are present – the first time such "courtship parental care" has been documented in any species.

As noted above, different species of voles vary in their sexual behavior, and these differences correlate with expression levels of vasopressin receptors in reward areas of the brain. Scientists were able to change adult male meadow voles' behavior to resemble that of monogamous prairie voles in experiments in which vasopressin receptors were introduced into the brain of male meadow voles.