Dacus

Abstract: A key is presented to the 42 species of opiine Braconidae previously collected in biological control programs directed against Ceratitis and Dacus s. l. Diagnostic features and present nomenclatural status are also discussed for these species. Biosteres oophilus (Fullaway) is treated as a synonym of Biosteres arisanus (Sonan), and B. watersi (Fullaway) as a synonym of B. dacusii (Cameron).

Abstract: During 1962–63 cane-fiber squares saturated with a solution of methyl eugenol-3% naled (by volume) and dropped from the air or suspended from trees eradicated a heavy infestation of oriental fruit flies, Dacus dorsalis Hendel, from the semi-isolated 33-square-mile Island of Rota, Mariana Islands. Most of the squares were dropped at 2-week intervals from an airplane flying over lines 1/5 mile apart. In inhabited areas permanent bait stations, re-treated monthly, were suspended from trees in lieu of aerial drops. Only 3.4 g of toxicant/acre were required for the entire operation. Male fly populations declined 99.6% within 1 generation. Virgin, sexually mature females were attracted and killed by the lure, but only after the male population was depressed 99%. Virgin females constituted 93% of flies caught in the 4th month; this response may have increased the efficiency of the method. Fly catches and fruit infestations ceased during the 6th month. The island has been free of oriental fruit flies for more than 24 months.

Abstract: Avian dispersal of seeds of the wild olive tree (Olea europaea var. sylvestris) was studied in Mediterranean shrubland, southern Spain. Fourteen species of small fru- givorous birds in the genera Sylvia, Turdus, Sturnus, and Erithacus accounted for 97.4% of the fruits consumed by birds. The significance of each bird species as an Olea fruit consumer was closely related to its abundance in the area and was not associated with its dependence on the fruit for food; this resulted in a highly asymmetric interaction between the plant and its dispersers. Fruit production differed greatly between two consecutive seasons. During an extremely dry year most trees aborted their entire fruit crop just after flowering. During the 2nd yr, both flower production and fruit set increased, and this resulted in larger crops of ripe fruit. Most fruits that ripened (96.2% of the final-sized fruits) during the year of low fruit pro- duction were consumed by dispersers (X = 93.9%), and incidence of fruit-damaging agents was low (6.0%). During the 2nd yr, fruit loss to the two main fruit predators, Dacus oleae (Tephritidae) and Prays oleae (Yponomeutidae), increased (X = 27.1%, range 1.1-52.3%). A satiation process took place during this year since fruit production exceeded the energy demand of the disperser assemblage, and this increased the potential for fruit loss to insect frugivores. Fruit removal by dispersers decreased (X = 5 2.4%), but the increase in fecundity during the 2nd yr for most of the trees compensated for this difference and resulted in a greater absolute number of seeds removed. Most variation in ripe fruit removal by birds was attributed to the interaction of dispersal- related plant traits with insect frugivores that determine post-ripening fruit losses. The types of higher order interactions that result from the action of birds, the pulp-damaging fly, and the seed-eating moth larva may damp, or reverse, any selective effect of a single system component on plant traits related to seed dispersal.

Abstract: The CLIMEX model was used to infer the climatic requirements of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), from the fruit fly’s observed geographical distribution in the Mediterranean region. The model indicated that the potential distribution was limited by cold to the north in Europe and by dryness in northern Africa and in the south of Spain and Portugal. The model was then used to estimate the potential geographical distribution of the species in Argentina and Australia. The results agreed with the observed distribution in Argentina and much of the historical distribution in Australia, but they did not agree with the present distribution in eastern Australia. In the latter region, another species of fruit fly, Bactrocera (Dacus) tryoni (Froggatt) has been credited with displacing C. capitata. Seasonal and year-to-year variation in climatic suitability was explored at three selected locations in Argentina. The results indicated that some detrimental effects of summer temperat...