Meeting Abstract
Competition for food resources can alter behavior in ways that influence disease dynamics. Resource competition can increase the frequency and intensity of intraspecific aggression, or alternatively, reduce the propensity for individuals to be social. Such changes in sociality could augment or diminish direct transmission of pathogens respectively. Limited resource availability can also increase indirect contact among individuals, thus facilitating environmental sources of pathogen transmission. Here we experimentally manipulated intraspecific competition and assessed effects on host behavior and pathogen transmission in a naturally occurring host-pathogen system. We varied the number of bird feeders available to captive flocks of 8-9 house finches Haemorhous mexicanus, and inoculated one bird per flock with Mycoplasma gallisepticum (MG), a bacterial pathogen that is transmitted both via direct contact and indirect exposure at bird feeders. Birds were fitted with passive integrated transponders to continuously track foraging behavior and social interactions at radio-frequency-identification equipped feeders. We found that the likelihood of MG transmission was significantly higher within low-competition flocks (4 feeders/flock) than high-competition flocks (2 feeders/flock), despite a significantly lower rate of intraspecific aggressive interactions within low-competition flocks. Here we discuss possible mechanisms for this transmission discrepancy including pathogen tolerance, increased sociality, and the relative frequency of exposure at bird feeders harboring MG.
