ABSTRACT. This study aimed to evaluate fitness components of Zaprionus indianus Gupta, 1970, a species recently introduced in Brazil and currently in process of colonization. Longevity, productivity, developmental speed and viability of flies sampled from a population from Mirassol (state of São Paulo, Brazil) were evaluated. Longevity was higher than that of some Indian populations and productivity was similar or higher than in other Drosophilidae. Time of development, one of the main fitness components for competition, was very similar to the values scored in Drosophila sturtevanti Duda, 1927, a species that occurs in high frequencies in the same area as Z. indianus. These data might contribute further for understanding the colonization success of this newcomer species in South America.KEYWORDS. Fitness components, productivity, viability, time of development, Zaprionus. (CHASSAGNARD & TSACAS, 1993;CHASSAGNARD, 1996) and Anaprionus, with 12 species from Australia and Southeastern Asia (TSACAS & CHASSAGNARD, 1990;GUPTA & GUPTA, 1991). Zaprionus indianus seems to be the unique species of Zaprionus subgenus that is spreading throughout the tropical regions, probably due to the intensification of the world fruit commerce (VILELA et al., 2001). This species occurs throughout Africa, India and Saudi Arabia, as well as in islands of the Indian Ocean (Comores, Madagascar, Seychelles, Mauritius and Réunion) and of the Atlantic Ocean (Canary and Saint Helena) (CHASSAGNARD & KRAAIJEVELD, 1991;CHASSAGNARD & TSACAS, 1993). In Africa, it has been found in 74 species of 31 botanical families; among them, several are native of the American continent (avocado, pineapple, guava and papaya) or have been here introduced (carambola, banana, citrus, mango and fig) (LACHAISE & TSACAS, 1983).The occurrence of Z. indianus in South America was first reported in Brazil (VILELA, 1999) and then in Uruguay (GOÑI et al., 2001). It has been suggested that this species may have been introduced in Brazil by airplane transportation from African or Asian countries to the city of São Paulo, possibly in meals (fruits for instance) offered to passengers (VILELA, 1999;TIDON et al., 2003). Zaprionus indianus has been found in all regions of Brazil (CASTRO & VALENTE, 2001;VILELA, 1999;VILELA et al., 2001;TIDON et al., 2003).Although Z. indianus has not been considered as a pest in the Afrotropical region, it seems to be reaching the pest status in the fig main producer areas of the state of São Paulo (Brazil). In 1999, 50% of the fig crops were lost due to oviposition of these flies (VILELA et al., 2001). Since Z. indianus has also been found in other tropical fruits, such as citrus, persimmon, guava, jambul and acerola (VILELA et al., 2001), it is possible that this species will become invasive in the culture of these agricultural products, thus causing damages to regional economies.Little information about Z. indianus reproductive biology is found in the literature. Therefore, the quantification of fitness components in laboratory is an important t...