Nonylphenol stimulates fecundity but not population growth rate (λ) of Folsomia candida

Abstract The toxicity of nonylphenol (NP) to springtails was pronounced at 40 mg/kg dry weight soil, at which no animals survived. Body length and fecundity were the individual life-history traits significantly stimulated by sublethal concentrations of NP during a 64-day experiment. However, the effects of NP on these traits did not result in a statistically significant increase in population growth rate ( λ ). Decomposition analysis indicated that fecundity was the main contributor to the (non-significant) changes observed in λ ⋅ However, since the elasticity of fecundity was very low, large changes in fecundity resulted in a minimal effect on λ ⋅ Juvenile survival had the highest elasticity of all traits, but was not affected by NP, and therefore did not contribute to effects on λ . This study confirms previous studies showing that effects of chemicals on individual life-history traits are attenuated at the population level and that λ is an appropriate endpoint for ecotoxicological studies.