Abstract: Larger male Caribbean fruit flies are more likely to be chosen as mates and defeat rivals in territorial contests. Yet males are smaller than females. Adaptive explanations for relatively small male size include (1) acceleration of male development to maximize female encounter rates, (2) selection for greater female size to increase fecundity, and (3) selection for body sizes most suitable for sexually dimorphic degrees of mobility, speed, and distance flight. None of these unambiguously accounts for the degree of sexual dimorphism. Male development is not accelerated relative to that of females. On average, males remain inside fruit longer than females and those males with extended development periods are smaller than more rapidly developing individuals. There is no evidence that female enlargement alone, presumably for greater fecundity, has generated the degree of dimorphism in the Caribbean fruit fly or other fruit flies. The relationship between dimorphism and mean female body size in 27 species of Tephritidae is the opposite of what would be predicted if differences in dimorphism were due to differences in unilateral female enlargement. Larger size in a species or in one sex of a species may be an adaptation for extensive flight. In general, among 32 species of fruit flies, as body size increases, wing shape becomes progressively more suited for distance flight. However, there are important exceptions to this correlation. Both sexual selection and nonadaptive allometries may contribute to the range of dimorphisms within the family.

Abstract: The present study constitutes the first attempt to construct a photographic map of the polytene chromosomes of Dacus oleae, a pest of the olive tree that causes serious financial damage in all olive oil producing countries. The map was constructed by using the larval fat body cells, the chromosomes of which are representative of the polytene chromosomes of other polytene tissues. In addition, the mitotic chromosomes of brain ganglia were examined, permitting tentative correlations between mitotic and polytene elements. This investigation shows that D. oleae is suitable for cytogenetic analysis in both mitotic and polytene chromosomes, a fact that may prove very useful for obtaining more detailed genetic information on the pest's natural populations.Key words: Dacus oleae, polytene chromosomes, mitotic chromosomes.

Abstract: The authors have examined the influence of the Dacus Oleae infestation on the aroma of the oils obtained from olives of Coratina and Nebbio varieties at different levels of attack. The results obtained indicated a worsening of the qualitative level of the oils obtained from increasing percentages of infested olives; these were found to have a great decrease of phenolic substances and higher contents of both volatile alcohols and aldehydes with an unpleasant sensation. Of particular interest was hexanal/total volatile alcohols ratio, in which having been well correlated with the extent of infestation, would permit one to establish in an objective manner, if and how much the olives from which an oil has been extracted have suffered a Dacus attack.

Abstract: The taxonomic identity and synonymy of four serious fruit fly pests, one of olives in Europe, and three Oriental species, two associated with citrus fruits and one with cucurbit fruits and vegetable, is clarified. Polistomimetes Enderlein is a new synonym of Tetradacus Miyake, which was originally described as a subgenus of Dacus, but is newly placed as a subgenus of Bactrocera. Heterodaculus Hardy is removed from synonymy with Polistomimetes. Mellesis citri Chen is a new synonym of B. minax (Enderlein); D. cheni Chao is a new synonym of B. tsuneonis (Miyake); and D. nubilus Hendel is replaced in synonymy with B. tau (Walker). Callantra splendida Perkins and D. discipennis Walker are transferred to the genus Bactrocera Macquart. The limits of the subgenera B. (Daculus) and B. (Tetradacus) are discussed; it is concluded that oviscape form separates those subgenera. B. (Daculus) includes the olive fly, B. oleae (Gmelin) and B. (Tetradacus) includes the Oriental citrus flies, B. minax (Enderlein) and B. tsuneonis (Miyake), plus three other species. It is also concluded that the presence or absence of anterior supra-alar setae and prescutellar acrostichal seatae should not be used in the diagnosis of Bactrocera subgenera. A lectotype of Polistomimetes minax Enderlein is designated.

Abstract: The response of male oriental fruit fly, Dacus dorsalis Hendel, to colored plastic bucket traps baited with methyleugenol was determined in a commercial guava, Psidium guajava L., orchard. When traps were placed close together on stakes, white and yellow traps caught the largest number of flies, whereas green, red, and black caught the fewest. When traps were placed in guava trees, no significant difference in fly captures occurred, although white traps caught the most flies and the same general trend in trap efficiency occurred. Results suggest that the attractiveness of traps is due primarily to intensity of reflected light. The potential for improving trap efficiency in D. dorsalis monitoring and control programs is discussed.

Abstract: The effect of pheromone (methyl eugenol) dispensers on the catches of male Dacus zonatus (Saunders) in the trap was tested under field conditions. Lure injected in cotton wicks captured male flies efficiently up to nine weeks. Though the mean number of males captured during first week in traps with cotton wick dispensers was comparatively less than cork sheet, cigarette filter tip, pith of sarkanda and blotting paper but it increased during five successive weeks and thereafter decreased. However trap catches decreased from second week onward with rest of the dispensers. The results manifest that cotton wick as a dispenser for methyl eugenol proved most efficient in attracting the flies for longer duration and thus had a potential usefulness for monitoring and control of D. zonatus. Zusammenfassung Freilanduntersuchungen uber verschiedene Dispenser fur Methyl-Eugenol zur Anlockung von Dacus zonatus (Saund.) (Dipt., Tephritidae) Es wurden Versuche mit dem Pheromon Methyl-Eugenol zum Fang der Mannchen von Dacus zonatus durchgefuhrt. Nach Injektion in Baumwolldochte wirkte das Pheromon bis zu 9 Wochen lang. Obgleich die mittlere Zahl gefangener Mannchen in Fallen mit Baumwolldocht-Dispensern zu Anfang vergleichsweise geringer war als bei Korkscheiben-, Zigarettenfilter-, Sarkanda-Mark und Loschpapier-Dispensern, stieg sie in den folgenden 5 Wochen an, um dann erst wieder abzunehmen, wahrend die Zahlen bei den anderen Dispensern ab der 2. Woche sanken. Die Ergebnisse zeigen, das Baumwolldochte als Dispenser fur Methyl-Eugenol sich zum Fang der mannlichen Fliegen am besten eignen, was bei der Anwendung von Pheromon zur Prognose und Bekampfung von D. zonatus zu beachten ist.

Abstract: The vapours of certain pure chemicals, typical of ripe fruits, elicited characteristic components of ovipositional behaviour from gravid Dacus tryoni (Froggat) in an olfactometer: the flies walked and flew upwind to the source of the vapour and then probed with their ovipositors. A range of alcohols, acids, ketones and esters having 2-6 carbon atoms were effective (1 and 10% of iso-butyric acid, n-butyric acid, methyl butyrate, ethyl butyrate, 2-butanone, ethyl lactate and ethyl acetate; and 10% concentrations of ethanol and 2-propanone). The most effective were 4-6 carbon acids, esters and ketones. Behavioural threshold for n-butyric acid vapour at 26°C was obtained from a 5×10-3% dilution in paraffin oil; maximum fly response occurred at about 200 times this concentration. Low concentrations of the 15-carbon sesquiterpene, α-farnesene, were also very effective, despite its lower volatility. These results suggest that at least three different types of alfactory sensory neurones are involved in the identification of fruit attractants by gravid D. tryoni.

Abstract: The ISMS reaction, which initially afforded a mixture of regioisomeric olefins, can now be controlled to produce only the exocyclic alkene. The ISMS methodology was used in a highly efficient synthesis of a Dacus oleae pheromone 8 .

Abstract: 1. 1. Population samples of Dacus cucurbitae from four localities in Peninsular Malaysia were analyzed for 5–12 gene-enzyme systems comprising 7–14 loci. 2. 2. Six loci, EST-F, HK-2, IDH, aMDH, PGM and PGD, were polymorphic. 3. 3. Hexokinase-2, isocitrate dehydrogenase, anodal malate dehydrogenase and phosphogluconate dehydrogenase were represented by two alleles each, while esterase-F and phosphoglucomutase were represented by three alleles each. 4. 4. Phosphoglucomutase showed greater variability than the other polymorphic loci, while phosphogluconate dehydrogenase was the least variable. 5. 5. The proportion of polymorphic loci ranged from 0.21 to 0.57, while the mean heterozygosity ranged from 0.09 to 0.23.

Abstract: The fine structure of the presumed rectal pheromone gland cells of male Dacus cucurbitae Coquillett, and of male and female Dacus latifrons (Hendel) was examined for the presence of those organelles described in the literature as characteristic of pheromone-secreting cells. D. cucurbitae possessed almost all of these organelles. In male D. latifrons , the cells possessed few of the organelles that characterize secreting cells. The epithelium in this species appears to be modified instead for stretching when the rectum is filled. The fine structure of the rectal epithelial cells of females of D. latifrons was quite different from that of cells of the males of this species.

Abstract: The Queensland fruit fly (Dacus tryoni) has established an association withnbacteria belonging to species of the family Enterobacteriaceae. When isolates ofnassociated bacteria were assayed for dinitrogen-fixing activity by the acetylenenreduction (AR) method, 5 of 27 from fruit surfaces and 3 of 26 from the alimentaryntracts of field-collected flies gave a positive result. These bacteria were members of the species Klebsiella oxytoca, K. pneumoniae and Enterobacter cloacae. As thenmicroflora of subtropical dacine flies is usually dominated by a single species, a smallnproportion of wild D. tryoni may be colonized by bacteria able to fix atmosphericnnitrogen.nTo determine the ability of colonizing bacteria to grow diazotrophically in vivo,nyoung laboratory-raised D. tryoni were allowed to feed once, overnight, on heavy growthnof K. oxytoca F15C, a field-collected fly isolate expressing nitrogenase activity betweenn2 and 16 nmol ethylene produced h-1 mg-1 dry wt of cells. AR activity associated withnthese flies was recorded from 4 days after feeding, peaked about 4 days later, thenndeclined to zero over the next 12 to 18 days. Nitrogenase activity associated withnD. tryoni ranged from 15 to 839 nmol ethylene produced g-1 live wt h-1 over incubationnperiods from 2 to 6 h. Sugar fed flies which had received no supplementary feeding werenalso associated with AR activity. Autochthonous dinitrogen-fixing bacteria present innthe laboratory environment can colonize the fly's alimentary tract then growndiazotrophically. When yeast hydrolysate was fed to flies associated with AR activity,ndinitrogen fixation by alimentary tract bacteria was reduced by 90 % in 2.5 h and hadnceased within 24 h. A direct (15N2) assay of the insect/diazotroph association showednthat between 0.485 and 1.427 mg of fixed dinitrogen per day was incorporated in situ bynbacteria colonizing the alimentary tract of D. tryoni. Benefits afforded to the hostninsect by the association may include the maintenance of a stable bacterial populationnas either a dietary supplement for growth factors and amino acids or a protectionnagainst the establishment of pathogens.nSurveys of the microflora of laboratory-raised D. tryoni indicated that thenaverage population was about 10 million bacteria per fly and confirmed that a singlenspecies of the Enterobacteriaceae, usually either K. oxytoca or E. cloacae, wasnpredominant. n

Abstract: Eclosion, longevity, and reproduction of three braconid parasitoid species that parasitized tephritid fruit flies exposed to azadiracthin were determined. Psytallia incise (Silvestri) and Diachasmimorpha longicaudata (Ashmead) developed in and eclosed from oriental fruit flies, Dacus dorsalis Hendel, exposed to azadirachtin concentrations that completely inhibited adult fly eclosion. Diachasmimorpha tryoni (Cameron) also eclosed from Mediterranean fruit fly, Ceratitis capitata (Wiedemann) exposed to concentrations of azadirachtin that inhibited fly eclosion. Lifespans of parasitoids that emerged from treated flies were not significantly different from controls. Reproduction of P. incisi that developed in flies exposed to azadirachtin concentrations of > 20 ppm was reduced 63-88%. D. longicaudata and D. tryoni reproduction was unaffected. The potential use ofneem-based insecticides in conjunction with biological control programs is discussed.