Abstract
Females of the solitary endoparasitic wasp Biosteres longicaudatus sometimes deposit >1 egg (superparasitism) in each larva of the Caribbean fruit fly host, Anastrepha suspensa. As host density increases, there is an inverse relationship between the level of superparasitism and the number of progeny produced/female. Larval parasitoid competition in superparasitized hosts causes an abrupt decline from >1 to 1 or B. longicaudatus, like other solitary endoparasitoids eliminates competitors by both combat and interference competitions. The latter case, presumably involves allelochemical toxins against conspecifics in the absence of physical encounter.