Project description:The impact of pesticides on amphibian metamorphosis may vary depending on developmental stage of individuals during the exposure period. Some anurans experience increased rates of development when exposure to the insecticide carbaryl occurs later in larval development. We exposed developing northern green frog tadpoles (Lithobates clamitans) to a 3 day pulsatile exposure of 1 mg/L carbaryl at 16 weeks relative to the starting free-swimming Gosner stage 25 (Gosner, 1960) and examined treatment effects on brain mRNA abundance profiles of Gosner stage 46 metamorphs using an amphibian cDNA microarray.