Whole body extract of Mediterranean fruit fly males elicits high attraction in virgin females

The search for effective female attractants emanating from the host or body of fruit flies has been an area of intensive research for over three decades. In the present study, bodies of male Mediterranean fruit flies, Ceratitis capitata (Wiedemann) (Diptera: Tephritidae), were extracted with diethyl ether or methanol and subjected to gas chromatography–mass spectrometry. Analysis revealed substantial qualitative and quantitative differences between males from a laboratory culture and wild males captured alive in an orchard. Most notably, the hydrocarbon sesquiterpene (±)‐α‐copaene, which is known to be involved in the sexual behaviour of the species, was found in substantial amounts in wild males, but was not detected in laboratory males. In laboratory tests, 15 laboratory or wild male equivalents of diethyl ether extracts or combined diethyl ether and methanol extracts, or, to a lesser extent, methanol extracts alone, were found to attract virgin females. In a citrus orchard, traps baited with combined diethyl ether and methanol extracts of wild males attracted significantly more virgin females than traps baited with various doses of pyranone or blends of other compounds identified in the extracts or reported in the literature, such as ethyl acetate, ethyl‐(E)‐3‐octenoate, and 1‐pyrroline. Traps baited with blends of compounds, however, displayed substantial attractiveness compared to control (non‐baited) traps. These results are important for better understanding the mating system of C. capitata as well as for further improving existing monitoring and control systems.     

Dispersed information diffusion with level and schema-based coordination in mobile peer to peer networks

Several open ended issues for high resource availability in mobile peer to peer networks have been examined in the recent past. Different approaches were conducted for supporting information distribution and availability, through guided or unguided packet diffusion. The majority of the recently proposed approaches try to benefit from the spatial characteristics of the dynamically varying topologies. In this work a directed information diffusion scheme is examined using a level and schema-based coordination, applied in mobile peer to peer networks. The prioritization degree of any requested advert is modeled and enables directed prioritized diffusions to end mobile users that are traversing a certain geographic region (location based advertisements). The proposed method is robust in disseminating redundant messages to users while maintaining connectivity through Gradual Energy Tree-based (GET) configuration. Simulation is performed for the examination and performance evaluation of the proposed scheme, taking into account the modeled prioritization as well as the diffusion accuracy by using the Hierarchical and Non-hierarchical GET configuration.

Lachers d'Opius concolor [Hym.: Braconidae] dans des populations de printemps deDacus oleae [Dipt.: Trypetidae]

Résumé Un lacher du braconideOpius concolor Szepl. a été effectué au printemps au cours de la première génération de multiplication de la mouche de l'oliveDacus oleae Gmel. dans l'oliveraie de Delphes. Il permet de constater que: le parasite s'installe normalement aux dépens des larves réceptives (troisième stade), il est apte à parasiter les larves deD. oleae présentes en haut et en bas de l'arbre, les pontes des femelles s'étalent sur deux semaines, le parasite est susceptible d'être hébergé par les pupes qui s'enfouissent dans le sol. La mortalité larvaire naturelle due à des causes non parasitaires est importante, notamment dans les olives tombées au sol et dans celles de la partie basse et ombragée de l'arbre.

---

Summary A release of the braconid parasitoidO. concolor Szepl. was made during spring (May) against the larval population of the olive fruit flyD. oleae Gmel. in a grove containing some trees which had heavily infested olive fruits which had overwintered. The parasitoid developed normally in the 3rd instar larvae of this population. Although it was present throughout the tree, during the 1st days it was more active in the upper part where 51% of receptive larvae were parasitized than in the lower where 18% were parasitized. After one week, these figures were 20% and 44% respectively. They have been calculated from counts ofDacus larvae containing either eggs or larvae.O. concolor had almost completely disappeared from the tree 2 weeks after the release because of fruit fall following high winds, although it was still possible to find both eggs and larvae in the appropriate host stages on the soil. The emergingO. concolor population was dominated by male adults, making up 74% of the numbers. The natural mortality ofD. oleae larvae not induced by the parasite factor was important in the area, especially in the fruits fallen onto the soil in which 28% of young larvae and 14% of 3rd instar larvae died. Higher mortality occurred from these factors in the upper crown than in the lower: 16% of young larvae and 7% of 3rd instar larvae died in the former situation but 7% and 2% respectively in the latter. Almost no parasitism from indigenous parasites was recorded.

     

The efficacy of an improved form of the mass-trapping method, forthe control of the olive fruit fly, Bactrocera oleae (Gmelin) (Dipt., Tephritidae): pilot-scale feasibility studies

Abstract:  The efficacy of an improved form of the mass-trapping method for the control of the olive fruit fly, Bactrocera oleae (Gmelin) was tested for 4 years in a pilot test at Tanagra Voeotia, Greece. Improvements consisted of the extension of the active life of the toxic trap used, active life referring both to its attracting and killing properties, as well as in trap deployment, which combined efficacy and low cost. The method was compared to bait sprays applied from the ground, which constitutes the current standard method for the control of this pest. Both pest population density and fruit infestation levels, the main parameters used for the evaluation of the two methods were considerably lower during all 4 years of tests in the orchards protected by mass trapping compared with those in the orchards protected by bait sprays. Furthermore no complementary measures were required in the mass-trapping orchards for acceptable crop protection, which was not the case under certain conditions, prior to the introduction of the recent improvements. The cost of the mass-trapping method was approximately US$ 0.40 per tree per year compared with US$ 0.35 for bait sprays (figures of the Greek Ministry of Agriculture). However, the mass-trapping method reduces the amount of insecticide used for olive protection by 99.5% (15 mg a.i. per tree per year as opposed to 3 g in the case of bait sprays). A considerable reduction in the cost of the mass-trapping method is expected with the extension of its use and the mass production of materials used, especially traps.