Immune system activation affects song and territorial defense

Abstract

Previous studies have demonstrated that bird song is influenced by infection. We investigated how mounting an immune response by mountain white-crowned sparrows (Zonotrichia leucophrys oriantha) affects specific aspects of territorial song and behavior. We used song playback to simulate a territorial intrusion and elicit baseline song and behavioral responses. Individuals were then either injected with a saline control or with a lipopolysaccharide (LPS) solution to induce an acute immune response, and posttreatment territorial song and behaviors in response to playback were recorded 1 day and 7 days later. The immune challenge significantly reduced the number of birds that sang compared with control individuals on Day 1. All birds that sang on Day 1 produced abnormal songs with fewer terminal notes, exhibited elevated alarm behavior, and tended to sing at slower rates. By Day 7, LPS treatment had no effect on the likelihood of singing, and song rates had returned to baseline levels, though songs were still sung with fewer terminal notes. Thus, our study shows that simply mounting an immune response to infection, as opposed to the actual infection per se is sufficient to impact avian song production. This study also suggests that for the most sensitive assessment of immune status, familiarity with an individual's song and behavior is necessary.

Physical competition increases testosterone among Amazonian forager-horticulturalists: a test of the ‘challenge hypothesis’

“…Previous studies find that poor environmental conditions or illness can reduce T-mediated reproductive or competitive behaviour in some avian species [43,44]. In these studies, lower T was associated with avoiding territorial behaviour that could induce a fight; thus facilitating avoidance of dangerous conflicts when an individual is in poor condition.…”

Birds receiving extra carotenoids keep singing during the sickness phase induced by inflammation

“…We performed one observation session of 45-60 min per day per aviary between 0900 h and 1300 h 1 day before immunization, and, respectively, 1, 2 and 4 days after immunization. Indeed, it is known that the inflammation caused by LPS can affect birdsong also 24 h after the challenge (Owen- Munoz et al 2010). Overall song rate was defined as the proportion of samples during which a male was singing (in any and all locations) compared to the total number of samples.…”

“…Avian song represents a good example in this respect, and several studies have reported an association between the condition of the immune system and song expression (Saino et al 1997;Møller et al 2000;Garamszegi et al 2004). More specifically, it has been shown that an immune activation can negatively affect song performance (Owen- Munoz et al 2010;Lopes et al 2012). For example, Munoz et al (2010) reported that white-crowned sparrows (Zonotrichia leucophrys oriantha, Oberholser, 1932) decreased their singing output and shifted their vocal performances from a structured song to a more simple alarm call when the immune system was activated.…”

“…More specifically, it has been shown that an immune activation can negatively affect song performance (Owen- Munoz et al 2010;Lopes et al 2012). For example, Munoz et al (2010) reported that white-crowned sparrows (Zonotrichia leucophrys oriantha, Oberholser, 1932) decreased their singing output and shifted their vocal performances from a structured song to a more simple alarm call when the immune system was activated.…”

“…In this study, we have investigated the possibility that dietary carotenoids alleviate the intensity of sickness behaviour enabling the birds to continue to perform singing behaviour. We immunized birds with a bacterial lipopolysaccharide (LPS), a non-pathogenic endotoxin that elicits solely an immune response, but without further complications as likely to result from the introduction of a pathogen (Munoz et al 2010). LPS triggers both the acute phase response and the humoral immune response, by mimicking an actual bacterial infection.…”