Life history and description of immature stages of Trupanea wheeleri Curran (Diptera : Tephritidae) on Asteraceae in southern California

Trupanea wheeleri Curran is a multivoltine, florivorous fruit fly (Diptera: Tephritidae) infesting flower heads of a wide variety of Asteraceae in Cal ifornia and the western half of the United States. Four new host-plant gene ra and five new species records are reported. To date, T. Wheeleri is known from seven tribes, 15 subtribes, 28 genera, and 47 species of hosts. The e gg, first through third instar larvae, and puparium are described and figur ed for the first time. The egg pedicel has one or two rows of aeropyles. Th e interspiracular processes of the first instar are large, broad, and multi branched. The anterior thoracic spiracles of the second instar each bear 7- 8 papillae, more than any previously studied congeneric species. The latera l spiracular complexes of the third instar are identical to that of T. impe rfecta (Coquillett), which is the first report of two species of Trupanea t hat share the same type and number of sensilla in their metathoracic and ab dominal, lateral spiracular complexes. The life cycle of T. wheeleri in sou thern California is of the aggregative type. The eggs are inserted alongsid e or into the corollas of florets and ovules upon which the first instars f eed in closed, preblossom flower heads. Second instars feed mainly on ovule s and florets of preblossom flower heads and soft achenes of open flower he ads; whereas, third instars feed on soft achenes in open and postblossom fl ower heads. Pupariation occurs inside the mature flower heads, from which t he adults emerge about the time that the achenes are shed. Several generati ons are produced on a variety of hosts during the spring, summer, and fall, and overwintering is as long-lived adults. Seven species of chalcidoid Hym enoptera were reared from individual puparia and mature flower heads bearin g puparia of T. wheeleri as solitary, primary, larval-pupal endoparasitoids : Eurytoma n. sp.? (Eurytomidae), Eurytoma obtusiventris Gahan (Eurytomidae ), Eurytoma veronia Bugbee (Eurytomidae), Eupelmus sp. (Eupelmidae), Mesopo lobus sp. (Pteromalidae), Pteromalus sp. (Pteromalidae), Torymus sp. (Torym idae).