Life history and description of immature stages of Neaspilota pubescens Freidberg and Mathis (Diptera : Tephritidae) on Lessingia filaginifolia (Hooker and Arnott) M. A. Lane (Asteraceae) in Southern California

Neaspilota pubescens Freidberg and Mathis is a univoltine, monophagous frui t fly (Diptera: Tephritidae) developing solely in the flower heads of Lessi ngia filaginifolia (Hooker and Arnott) M. A. Lane (Asteraceae) belonging to the subtribe Solidagininae of the tribe Astereae in southern California. T he egg, second- and third-instar larvae, and puparium are described and fig ured. The anterior thoracic spiracle of the second instar has five papillae , reduced to two papillae in the third instar. The second instar has seven oral ridges and the third instar eight oral ridges, which, except for the m ost ventral, eight oral ridge in the latter instar, are ventrally toothed. The arrangement of these oral ridges in a vertical series lateral to the or al cavity is a distinguishing generic character. The larvae feed mainly on the ovules and soft achenes as first and second instars; however, as third instars, they may extend their feeding into the receptacle and supplement t heir diet with sap. The nonfeeding prepuparium overwinters in a protective cell that occupies much of the excavated flower head and is formed of ovule -, achene-, chaff-, pappus-, and corolla-fragments impregnated with excess sap and liquid feces that harden when dry. A few prepuparia pupate and emer ge from their cells in the late summer and probably overwinter as adults, b ut most pupariate during the next year in late spring, and emerge as adults that aggregate on preblossom host plants to mate and subsequently oviposit . Pteromalus sp. (Hymenoptera: Pteromalidae) was reared as a solitary, larv al-pupal endoparasitoid from a puparium of N. pubescens.