Colorful network: pair-bonding temporal dynamics involve sexual signals and impact reproduction

Mate choice and pair-bonding are the products of complex decisions involving repeated social interactions over time. They generally rely on multiple sexual signals and behaviors, depending on the phenotype and experiences of the chooser and are affected by environmental conditions and competition for mate access. However, studies investigating the mechanisms of mate selection often ignore the dynamic aspects of the pair formation. In this study, we used social network analyses to (1) describe sexual interactions over time in multiple groups of captive zebra finches (Taeniopygia guttata), (2) ask how individual sexual signals and body condition relate to pair-bonding temporal dynamics, and (3) investigate whether sexual networks influence assortative mating and reproductive performance. We followed sexual interactions of 8 sex-balanced groups of 8 individuals to extract social network metrics over 8 sessions of observation. We assessed individual body condition, sexual signals and couples’ pairing latency, laying date, clutch size, and embryo viability. Pair-bonding dynamics were first characterized by song interactions between most individuals, then by numerous allopreening and clumping behaviors, targeting more specific partners. More colorful individuals became engaged in more sexual interactions more rapidly, and such network dynamics explained assortative mating for beak color. Interestingly, being involved in song interactions was negatively associated with reproductive performances, while the reverse was true for being involved in allopreening and clumping interactions. Our study highlights the need to study pair-bonding dynamics to better understand how variations in individual phenotype within sexual networks explain assortative mating and reproductive performance in monogamous species.