It has been demonstrated that phenotypic plasticity and genotype by environment interaction are important for coping with new and heterogeneous environments during invasions.Zaprionus indianus Gupta (Diptera: Drosophilidae) is an Afrotropical invasive fly species introduced to the South American continent in 1999.This species is generalist and polyphagous,since it develops and feeds in several different fruit species.These characteristics of Z.indianus suggest that phenotypic plasticity and genotype by environment interaction may be important in this species invasion process.In this sense,our aim was to investigate the role of genetic variation for phenotypic plasticity (genotype by environment interaction) in Z.indianus invasion of the South American continent.Specifically,we quantified quantitative genetic variation and genotype by environment interactions of morphological and life history traits in different developmental environments,that is,host fruits.This was done in different populations in the invasive range ofZ.indianus in Argentina.Results showed that Z.indianus populations have considerable amounts of quantitative genetic variation.Also,genotype by environment interactions was detected for the different traits analyzed in response to the different developmental environments.Interestingly,the amounts and patterns of these parameters differed between populations.We interpreted these results as the existence of differences in evolutionary potential between populations that have an important role in the short-and long-term success of the Z.indianus invasion process.