We studied the effects of maternal social stress induced by high density on offspring immunocompetence by experimentally altering population densities in field enclosures. We established high-density and low-density populations, with two replicates per density, in 4 enclosures (30 m×50 m). F1 generation individuals born into the enclosures were taken to laboratory and housed in standardized conditions with ambient light and temperature until sexual maturity. We tested serum corticosterone concentrations of ...