Meeting Abstract
Naturally-occurring environmental factors shape developmental trajectories to produce variable phenotypes, a phenomenon called developmental phenotypic plasticity. Developmental phenotypic plasticity has been demonstrated for numerous behavioral and morphological traits and can have important effects on fitness. Surprisingly few studies have examined phenotypic plasticity of the nervous system in response to naturally-occurring environmental variation experienced during development. Here, we asked whether the brain is developmentally plastic by exposing larval amphibians to natural and anthropogenic factors. Leopard frog tadpoles were exposed to predator cues, low food, or sublethal concentrations of the pesticide chlorpyrifos. Tadpoles in the experimental treatments grew more slowly than controls, although developmental rates and survival were similar. Brains from tadpoles exposed to predator cues and a low dose of chlorpyrifos were relatively narrower and shorter in several dimensions compared to those of control tadpoles and tadpoles with low food availability. Changes in brain morphology present in the tadpole stage were no longer present in metamorphs. Our results show that brain morphology is a developmentally plastic trait and it responds to both natural and anthropogenic forces. This is one of the first studies to show that exposure to sublethal concentrations of pesticide affects brain morphology.
