Simulated infection alters the behavior of pair bonded songbirds and their healthy neighbors

While infection and perceived infection risk can influence social and
reproductive behavior in several taxa, relatively little is known about
how infection specifically affects pair bond behaviors. Some pair bond
maintenance behaviors may be costly to maintain during infection, and
infection could promote avoidance behaviors within an established pair.
Many species exhibiting pair bonds are part of larger social groups, and
behavioral shifts in established pairs can result in altered extra-pair
contact rates that could also shape disease transmission. Using captive
zebra finches (Taeniopygia guttata), we examined how an immune challenge
with lipopolysaccharide (LPS) influences activity, social behavior, and
pair bond maintenance behaviors in established pairs and their healthy
neighbors. We observed shifts in individual and pair maintenance behaviors
in both immune-challenged pairs and healthy pairs exposed to a social cue
of infection (sick conspecifics). Specifically, LPS-challenged birds
decreased activity and social interaction attempts relative to control
birds, consistent with LPS-induced sickness behavior. LPS-challenged birds
also increased the frequency of clumping (perching together in bodily
contact) between individuals within a pair. Healthy birds exposed to
immune-challenged conspecifics decreased flight activity and increased
self-preening, behaviors which could function to limit infection risk.
Exploring how both infection and the perceived risk of infection shape
behaviors within and among paired individuals will increase our
understanding of the role of social behaviors in shaping disease dynamics.