Prior research on how to facilitate individuals' participation in wiki knowledge contribution generally pays little attention to the differentiation of knowledge contributions and the embeddedness of individual team members in team context. This paper examines how an individual's epistemic motivation and team task reflexivity interact to jointly influence adding, deleting and revising behaviors in distinct ways. Empirical data of 166 university students in 51 teams support our hypotheses. Individuals' adding, deleting and revising behaviors on wikis are influenced differently by the interactive effect of individual epistemic motivation and team task reflexivity. First, the positive relationship between epistemic motivation and adding behaviors is stronger when the team's task reflexivity is high. Second, the epistemic motivation stimulates deleting behaviors only when team task reflexivity is high. Third, epistemic motivation is significantly associated with more revising behaviors no matter the level of task reflexivity is high or low.