The impact of alien species on non-target native species is a cause for concern. This concern is especially relevant in the Hawaiian archipelago due to its high level of endemicity and long history of biological control introductions. The endemic Hawaiian moth Udea stellata has seven alien parasitoids associated with it, two purposely introduced, and five adventive. Pipturus spp., the endemic host plants of U. stellata are distributed across a wide range of habitats in Hawai’i, creating the opportunity to investigate various environmental conditions that might influence the infiltration of exotic parasitoids and their levels of attack. Partial life table studies were conducted in five sites varying in environmental conditions during fall 2005 and Spring-Summer 2006 with the aim to determine the relative contribution of each parasitoid species, as mortality factors, to the population dynamics of U. stellata by estimating k-factors. Standardized collections of wild larvae were conducted at the same time and location that the life table studies were carried out. Parasitism of sentinel larvae was lower than parasitism of wild larvae at all sites. The major mortality factor at all larval stages was disappearance, which is assumed to be a result of predation and dispersal of larvae. Adventive parasitoids were responsible for the majority of the parasitism in this study system. Addressing current ecological impacts of alien parasitoids on native species is of particular importance for developing more efficient means to quantify the risks of future introductions.