Meeting Abstract
Acute pathogen infections are energetically demanding events that can induce substantial behavioral changes within hosts and thus influence pathogen spread. To date, few studies of vertebrates have examined how infection with a directly-transmitted pathogen influences host sociality. Juvenile house finches are highly gregarious after reaching nutritional independence, forming large feeding flocks. In part due to this sociality, juveniles are particularly susceptible to infection by the bacterial pathogen Mycoplasma gallisepticum (MG). Therefore, any changes in sociality during active infection are likely to have consequences for the transmission of disease throughout these majority-juvenile flocks. However, it remains unknown how infection early in the juvenile stage (<3 months post-hatch) influences behavior and sociality in house finches. To test this, we inoculated 33 wild-caught juvenile house finches with MG or media alone (sham control) within 3 months post-hatch. At the peak of infection, all birds were run through a modified partner choice assay, where they were given the choice to feed and perch adjacent to a small flock or alone. Preliminary data from a subset of house finches suggest that they show heterogeneity in their behavioral preference which relates to the severity of MG-induced disease. Birds with more severe disease exhibited the lethargy seen in prior studies of MG-infected adults, and thus these birds appeared indifferent to flock presence or absence. In contrast, individuals with less severe disease appear to preferentially feed or perch near the flock. Our results have important implications for the spread of MG among hatch-year birds, which make up the largest proportion of both infected and susceptible hosts in natural populations.
