In this paper we present data not published, but yet cited in a previous work concerning with the subterranean community from the Grotta del Fiume, in Central Italy (Sarbu et al 2000). In particular, we discuss the role of food abundance and distribution as a possible determinant of the population genetic structure of Androniscus dentiger, a cave-dweller terrestrial isopod inhabiting that cave, where guano and chemoautotrophic bacteria are trophic sources, spottily distributed in different areas.