Date of Award


Publication Type

Master Thesis

Degree Name



Biological Sciences


Duetting, Mate guarding, Parental commitment, Paternity guarding, Rufous-and-white Wren, Thryophilus rufalbus


Mennill, Daniel




In many tropical animals, male and female breeding partners combine their vocalizations to produce elaborate vocal duets. Although duets are produced by diverse animal taxa, the functions of these coordinated vocalizations remain poorly understood. In this thesis, I explored the ecology and evolution of vocal duetting behaviour by testing two poorly-studied hypotheses for duet function in a Neotropical duetting songbird, the Rufous-and-white Wren (Thryophilus rufalbus). The Paternity Guarding Hypothesis states that male animals create duets with their females to guard against other males seeking mating opportunities. I used a playback experiment to test this hypothesis by first simulating an intrusion from a rival male, and then simulating a subject males breeding partner to give him opportunities to create duets with his female during both the fertile and non-fertile periods. Consistent with predictions of the Paternity Guarding Hypothesis, males created more duets with their partners during the fertile period compared to the non-fertile period, suggesting that they used duets to acoustically protect their parentage. The Signalling Commitment Hypothesis states that singing duets with a partner signals willingness or ability to invest effort into a monogamous partnership. I tested this hypothesis by investigating the relationship between duetting behaviour and future parental investment. I found no evidence of a positive relationship between male or female duetting behaviour and future investment in nest-building or nestling-provisioning, and therefore my data provide no support for the Signalling Commitment Hypothesis. My research provides new insight into the evolution and functions of vocal duets in tropical animals, revealing that duets play an important role in paternity guarding, but do not signal future parental commitment in Rufous-and-white Wrens.