Collembola are known to feed on a wide range of soil material, predominantly rhizosphere fungi, and root-derived substances. However, diet switching from these usual food sources to living roots (herbivory) was previously demonstrated for one species of collembola, Protaphorura fimata, a euedaphic species. The objective of this study was to determine if diet switching can be applied to another collembola species, Folsomia candida Willem. This hemiedaphic species was given different combinations of maize plants (-13.28% δ¹³C, 3% δ¹⁵N) and ¹⁵N-enriched rye grass litter (-28.88% δ¹³C, 17 516.86% δ¹⁵N) in a C₃ soil system (-27.27% δ¹³C, 5.27% δ¹⁵N) under controlled conditions. After 8 wk, there was clear evidence of root feeding because the δ¹³C signature in collembola tissue was -19.28% in the presence of maize plants alone and -18.29% with maize plants grown in soil mixed with ryegrass litter, whereas collembola in unplanted soil microcosms had a δ¹³C signature of -23.66%. Data analysis with a two-source isotope mixing model indicates that up to 60% of the carbon requirements of F. candida were derived from living maize roots. Whether collembola root feeding is due to grazing on roots directly or on mycorrhiza (root-fungus association) requires further investigation.