Feeder use predicts both acquisition and transmission of a contagious pathogen in a north american songbird

Abstract

Individual heterogeneity can influence the dynamics of infectious diseases inwildlife and humans alike. Thus, recentwork has sought to identify behaviouralcharacteristics that contribute disproportionately to individual variationin pathogen acquisition (super-receiving) or transmission (super-spreading).However, it remains unknown whether the same behaviours enhance bothacquisition and transmission, a scenario likely to result in explosive epidemics.Here, we examined this possibility in an ecologically relevant host–pathogensystem: house finches and their bacterial pathogen, Mycoplasma gallisepticum,which causes severe conjunctivitis.We examined behaviours likely to influencedisease acquisition (feeder use, aggression, social network affiliations) in anobservational field study, finding that the timean individual spends on bird feedersbest predicted the risk of conjunctivitis. To testwhether this behaviour alsoinfluences the likelihood of transmitting M. gallisepticum, we experimentallyinoculated individuals based on feeding behaviour and tracked epidemicswithin captive flocks. As predicted, transmission was fastest when birds thatspent the most time on feeders initiated the epidemic. Our results suggestthat the same behaviour underlies both pathogen acquisition and transmissionin this system and potentially others. Identifying individuals that exhibit suchbehaviours is critical for disease management.