PROC. ENTOMOL. SOC. WASH. 87(3). 1985. pp. 564-571 HOST-PLANT RELATIONS OF TRUPANEA SPP. (DIPTERA: TEPHRITIDAE) IN SOUTHERN CALIFORNIA Richard D. Goeden Department of Entomology, University of California, Riverside, California 92521. Abstract. — Mdiny new rearing records are reported for nine of 15 species of Tfiipanca occurring in California. The host relations of all 1 5 species are assessed, including two species for which hosts remain unknown, two monophagous species, five oligophagous species, and si,\ generalist species, all restricted to Asteraceae. The numbers of flies reared from flower head samples from the different hosts of each species of Trupanea also varied considerably. Five years ago I began long-term studies on the biology and ecology of flower-head infesting and gall-forming fruit flies (Diptera: Tephritidae) in southern Cal-ifornia, that section of the state defined and treated by Munz (1974). I report here many new rearing records for several species of Trupanea. the most common genus of nonfrugivorous Tephritidae encountered in southern California, and briefly characterize their host affinities in light of these new records. Materials and Methods Mature ffower heads of Asteraceae were sampled as encountered during wide-ranging field research on a variety of entomological projects throughout southern California during 1980-1984. Samples of excised heads and a few whole plants for use in identification were transported in individual, sealed, 23 x 30.5-cm, polyethylene plastic bags in a cold chest to the University of California at Riv-erside. The number of heads sampled varied with their availability and inversely with their size, but usually comprised a full bag of one to several hundred heads. Following temporary storage for up to 1 week in a refrigerator at 2°C, the plants were identified and the flower head samples separately caged in the insectary of the Division of Biological Control at 26 ± TC and a 12-h or 16-h photoperiod in glass-topped, wooden, sleeve cages described by Gilstrap and Goeden (1974). Samples were spread on the bare cage floors and held for 2 weeks to 1 month, depending on the amount and duration of fly emergence. A hygroscopic mixture of honey (five parts) : yeast hydrolyzate (two parts) narrowly streaked on the un-derside of the cage top provided a temporary food and moisture source for emerged flies. Bi-weekly collections of the fully colored, 2-3 day old flies were made and the number and sex of all tephritid species recovered from each sample recorded. Results New host-plant genus or species rearing records determined by comparison with Wasbauer (1972) for nine of 15 species of Trupanea reported from southern
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