PROC. ENTOMOL. SOC. WASH. 92(1), 1990, pp. 66-75 MATING BEHAVIOR OF ACWRINA MEXICAN A (ACZEL) (DIPTERA: TEPHRITIDAE) John Jenkins Department of Entomology, University of Arizona, Tucson, Arizona 85721 (Present address: Department of Zoology, Natural Science Building, Michigan State University, East Lansing, Michigan 48824-1 1 15). ^toracV.— Observations on the mating behavior of Aciurina mexicana (Aczel) in the laboratory are presented. Courtship and agonistic displays are named and described in detail. These displays include stereotypic body postures and wing movements, nuptial feeding, and abdominal inflation with odor production by males. Preliminary observations suggest that the male's nuptial gift is produced from the crop, and the source of the male odor is the abdominal pleura. Mating behavior of ,4. mexicana is compared with other Aciunna species and tephritid flies generally. Potential use of mating behavior in fruit fly systematics is noted. Key Words: Tephritidae, Aciurina, mating behavior, sexual displays, nuptial gift, pher-omone, systematics At least 12 species oi Aciurina occur in the western United States and northern Mexico (Steyskal 1984, Dodson and George 1986). Larvae of the species for which host plants are known form galls on asteraceous plants, primarily Chrysothamnus species (Steyskal 1984, Dodson 1987b). Mating behavior has been observed for a number of Aciurina species. Tauber and Tauber (1967) reported the reproductive behavior and biology of Aciurina ferruginea (Doane) from California. Wangberg (1981) commented on the mating behavior of A. ferruginea. A. maculata (Cole), A. semilu-cida (Bates), A. trixa Curran, and an un-described species (probably A. idahoensis Steyskal— see Steyskal ) from Idaho. Dodson (1987b) described the mating be-havior of .4. trixa in New Mexico. Dodson (1987b) predicted that most species of Aciurina would exhibit a similar mating strategy which he termed the "male-searching mating system." In this system. males move about the host plant scanning for conspecifics and attempt to copulate with any females encountered. Evidently, court-ship is limited to a few brief wing displays and may not precede attempts at copula-tion. Successful mating is dependent more on a male's ability to maintain a mounted position on a female (Dodson pers. comm.). Aciurina mexicana (Aczel) occurs in southern Arizona, southern California, and northern Mexico where larvae form stem galls on Baccharis sarothroides Gray (Stey-skal 1984). Contrary to what has been re-ported for other Aciurina species, precop-ulatory behavior in A. mexicana is protracted and involves a number of com-plex sexual displays. This paper describes the mating behavior of A. mexicana. Materials and Methods Specimens used in this study were swept from B. sarothroides located 14.3 km SE of Continental, Ariz. (Pima Co.) on 16 Feb.