Josh Snodgrass: University of Oregon

Immune function is an energetically costly physiological activity that can divert calories and other resources away from less immediately essential life history functions such as growth. However, direct evidence for immune-related tradeoffs among humans remains sparse. In this talk, I discuss longitudinal research among Shuar children (4-11 years old) that uses high-resolution linear growth data and dried blood spot samples for four immune measures. This research documents consistent negative effects of immune function on growth, with children experiencing up to 49% growth reduction during periods of mildly elevated immune activity. Additional findings show that tradeoffs are immunologically and temporally diverse, and also document a particularly detrimental impact of acute inflammation on growth though these inflammation-related tradeoffs with growth are buffered by body fat. I conclude by discussing the role of immune-related tradeoffs in driving patterns of human growth faltering, developmental metabolic plasticity, and life history evolution.