LIFE-HISTORY, COURTSHIP, AND MATING-BEHAVIOR OF THE GALL-FORMING ACIURINA-TRIXA (DIPTERA, TEPHRITIDAE) ON CHRYSOTHAMNUS-NAUSEOSUS HOLOLEUCUS (ASTERACEAE)

Life history and reproductive behavior of the Aciurina trixa Curran (D iptera: Tephritidae) on a new host plant subspecies, Chrysothamnus nau seosus hololeucus (Asteraceae) is described from a two-year study. Egg s are laid on axillary buds formed in the previous year. After egg hat ch, larval feeding induces a spheroid gall. The larva feeds on the inn ermost gall tissue while the gall continues to grow until the third la rval instar pupates. Sex ratios were female-biased (1989 - 1.00:1.49; 1990 - 1.00:1.17). Wing movements and auditory signals were observed d uring courtship and in agonistic encounters with siblings. Courtship a nd mating averaged 104 min (1 SE +/- 38 min) and 159 min (1 SE +/- 7 m in), respectively. Soon after emergence and mating, females started se arching for oviposition sites. Our data are compared with other A. tri xa populations attacking other subspecies of rabbitbrush in Idaho and New Mexico.