Life history and description of immature stages of Trupanea pseudovicina Hering (Diptera: Tephritidae) on Porophyllum gracile Bentham in southern California

Trupanea pseudovicina Hering is a monophagous, univoltine fruit fly (Diptera: Tephritidae) infesting flower heads of Porophyllum gracile Bentham (Asteraceae) in southern California, but may be oligophagous on still-unknown hosts in other southwestern United States. The egg, first-third instar larvae, and puparia are described and figured for the first time. The immature stages of T. pseudovicina are similar to those of five other California congeners described to date, with only the lateral spiracular complex of the third instars differing among these six species. The life cycle is of the aggregative type in southern California. The adults are long lived and comprise the over-summering and over-wintering stage that returns in spring to oviposit in the preblossom flower heads of P. gracile. An average of 2.5 (range: 1-7) eggs were oviposited, mostly singly or side-by-side in pairs, but also in packets of up to five, by one or more females in preblossom flower heads. First and early-second instars feed mostly on florets and ovules in preblossom heads. Late-second and third instars feed on soft achenes, not pitting the receptacles. Pupariation occurs in the open flower heads, within which an average of 30% of the florets/soft achenes were destroyed in heads containing puparia. Five species of chalcidoid Hymenoptera were reared from individual puparia and mature flower heads bearing T. pseudovicina puparia as solitary, larval-pupal endoparasitoids: Colotrechnus sp. (Eulophidae), Eurytoma n. sp, nr. levivultus Bugbee, Eurytoma sp. (1 female) (Eurytomidae), Halticoptera sp. (Pteromalidae), and Pteromalus sp. (Pteromalidae).