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Abstract. 1. Atriplex canescens (Pursh) Nuttall and A.polycarpa (Torrey) Watson (Chenopodiaceae) support twelve morphologically distinct gall types in southern California. Thirty‐seven common species of parasitoids, predators and inquilines are associated with these galls.2. The galls incited by eight members of the Asphondylia atriplicis Cockerell (Diptera: Cecidomyiidae) species complex are linked into a single, interacting community through shared hymenopterous parasitoids and inquilines.3. Cluster analysis (UPGMA) grouped the fifteen most common species of Chalcidoidea into three host guilds of five species each: (1) specialists in tumour stem and blister leaf galls on A.canescens, (2) specialists in woolly stem galls on A.poiycarpa, and (3) generalists that attack all galls. Guild 1 dominated the galls with which it was primarily associated, while guild 3 dominated the remainder.4. The abundances of the parasitoids of the tumour stem and blister leaf galls were negatively correlated with the abundances of two organizer species, a gall‐forming inquiline, Tetrastichus cecidobroter Gordh and Hawkins, and an internal, larval—pupal parasitoid, Tetrastichus sp. B. The abundances of nine of the twelve most common chalcidoids were not correlated with the abundances of all coaccurring species in six other galls.5. Host seasonality partly determines parasitoid population dynamics and guild structure. Parasitoid dominance increased with gall duration, suggesting that parasitoid competition depends on resource stability. The two continuously available galls were dominated by their specialist guild, while all seasonal galls were dominated by generalists. The subdominant specialists of woolly stem galls may represent competitively inferior species that utilize those galls opportunistically, because of the gall's widespread distribution and 9–10 month yearly availability.6. Sites in the Colorado Desert and chaparral that supported several gall types showed stable relative abundances of the major parasitoid species, whereas sites in the Mojave Desert that supported only woolly stem galls had unpredictable parasitoid species assemblages.7. The competitive success of Atriplex gall parasitoids may depend primarily on voltinism (multivoltine species dominated univoltine species) and mode of feeding (phytophagous, mixed entomophagous—phytophagous and facultatively hyperparasitic species in general dominated strict primary parasitoids).

This review is the first comprehensive treatment of the biology of nonfrugivorous fruit flies of the family Tephritidae. Feeding habits of destructive and useful species, morphology of immature stages, and hypotheses regarding structural homology and the evolutionary biology of nonfrugivorous tephritids are reviewed, including zoogeography and theories involving resource heterogeneity, guild structure, resource partitioning, resource utilization, facultative niche exploitation, extrinsic and intrinsic factors, host associations, seasonal distribution and phenology, aggregative and circumnatal life history strategies, voltinism, diapause, aestivation, oviposition site, clutch size, and supernumerary oviposition. PERSPECTIVES AND OVERVIEWThere is no comprehensive family-wide review of the biology of tephritid fruit flies. Reviews exist that focus on economically important taxa within the family (2,8,105,127), discuss regional faunas (9,14,20, 64,86,100,126), or treat one related subject such as gall formation by tephritids (18) or tephritids used in biological control of weeds (67,85,118,121). These reviews are extremely useful and taken together provide good coverage of the Tephritidae, except for a comprehensive picture of the biology and ecology of nonfrugivorous species.Our goal is to review important aspects of nonfrugivorous tephritid biology and ecology, to highlight relevant hypotheses that have been developed, and to suggest where future research may lead. Accordingly, we do not re-review the

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This publication summarizes 25 years of heretofore unreported efforts to effect the biological control of prickly pear cacti infesting rangeland on Santa Cruz Island, situated off the coast of southern California. To date, partial to substantial biological control of the pest cacti, Opuntia littoralis (Engelmann) Cockerell, O. oricola Philbrick, and their hybrids, has been achieved. The principal biological control agent is a cochineal insect, Dactylopius sp., which is native to the southern California mainland. It was introduced to the island free of its principal natural enemies-Hyperaspis taenlata significanis Casey and Laetilia coccidioora (Comstock)-and has multiplied markedly, at the same time destroying numerous clumps of cacti throughout the island. Effective range management practices, i.e., eradication of wild sheep and restrained cattle grazing, have aided the biological control efforts, and both have resulted in the return and persistence of annual grasses on formerly overgrazed and cacti-infested grazing lands. The coreid bugs, Cbelinidea tabulata (Burmeister) and C. vittiger Uhler, were also successfully introduced to Santa Cruz Island from Texas and mainland California, respectively, but neither species is thought significant as a biological control agent. The cactus-feeding phycitids, Olycella [unctolineella (Hulst), Melitara dentata (Grote), and M. prodenialis Walker, were not successfully colonized on Santa Cruz Island.