Gérald Franz

Abstract One of the main obstacles for a wider use of the Sterile Insect Technique (SIT) against the Mediterranean fruit fly (medfly) is the damage commercial fruit suffers due to sterile female stings. To overcome this obstacle, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture has played a leading role in sponsoring and carrying out research to develop medfly genetic sexing strains that allow male‐only SIT releases. Recently, as a result of this continued FAO/IAEA effort, genetic sexing strains based on a temperature sensitive lethal ( tsl ) mutation have been developed at the IAEA Laboratories at Seibersdorf. Unlike previous pupal color sexing strains, these ‘second generation’ sexing strains allow female killing at an early (embryonal) stage. In addition, they are essentially stable under mass rearing conditions. This represents an important breakthrough because both of these attributes were considered indispensable for genetic sexing strains with any potential to replace conventional strains with both sexes in large scale sterile medfly production facilities. Besides the considerable savings in the costs of release and field monitoring, genetic sexing strains in field tests have shown severalfold increases in the effectiveness of the SIT as compared with the standard strains involving males and females. When releasing both males and females, sterile males are apparently not used effectively, because they use their limited sperm mostly to mate with sterile females and because they do not disperse widely in the presence of these females. When males only are released, however, they disperse much further in search of wild females and compete more intensely with wild males for wild females. As a result of the availability of usable male‐only strains, and the demonstration of their increased effectiveness, the applicability of the SIT against medfly has increased in two different ways. Highly developed commercial fruit growing regions, that previously had excluded application of SIT because of the fruit damage due to sterile female stings, are now reconsidering such free area/exclusion programs. More‐importantly, sterile male releases can now also be used for routine control purposes, rather than only for eradication programs, partially or fully replacing chemical bait‐sprays during the fruiting seasons.

The mechanisms of sound production by the splashes made by the gas-to-liquid entry of objects are discussed. The sound from the splash is considered to be associated with acoustic multipoles of all orders, the main ones being simple sources, dipoles, and quadrupoles. The orders of the multipoles that predominate during the various phases of the splash are estimated from the flow and boundary conditions. The sounds radiated into the water by the low-velocity vertical entry of single water droplets, sprays of water droplets, and various other objects, such as spheres, cones, and wedges, have been measured and found to have the characteristics of acoustic dipoles. The extensive experimental data on the spectrum of the underwater sound from the splashes of droplets and sprays and the scaling laws for dipoles are used to estimate the spectrum levels of the underwater sound from the splashing of rain on the surface of a sea in terms of the rate of rainfall.

Journal Article Minos, a new transposable element form Drosophila hydei is a member of the Tc1-like family of transposons Get access Gerald Franz, Gerald Franz 1Institute of molecular Biology and Biotechnology, Research Center of Crete, FO.R.T.H.PO Box 1527, Heraklion 711 10, Crete + Present address: Entomology Unit, IAEA Laboratories, A-244 Seibersdorf, Austria Search for other works by this author on: Oxford Academic PubMed Google Scholar Charalambos Savakis Charalambos Savakis * 1Institute of molecular Biology and Biotechnology, Research Center of Crete, FO.R.T.H.PO Box 1527, Heraklion 711 10, Crete2Department of Medical Sciences, University of Crete Medical SchoolHeraklion, Crete, Greece * To whom correspondence should be addressed Search for other works by this author on: Oxford Academic PubMed Google Scholar Nucleic Acids Research, Volume 19, Issue 23, 11 December 1991, Page 6646, https://doi.org/10.1093/nar/19.23.6646 Published: 11 December 1991 Article history Received: 23 September 1991 Published: 11 December 1991

BACKGROUND: The sterile insect technique (SIT) is an environment-friendly method used in area-wide pest management of the Mediterranean fruit fly Ceratitis capitata (Wiedemann; Diptera: Tephritidae). Ionizing radiation used to generate reproductive sterility in the mass-reared populations before release leads to reduction of competitiveness. RESULTS: Here, we present a first alternative reproductive sterility system for medfly based on transgenic embryonic lethality. This system is dependent on newly isolated medfly promoter/enhancer elements of cellularization-specifically-expressed genes. These elements act differently in expression strength and their ability to drive lethal effector gene activation. Moreover, position effects strongly influence the efficiency of the system. Out of 60 combinations of driver and effector construct integrations, several lines resulted in larval and pupal lethality with one line showing complete embryonic lethality. This line was highly competitive to wildtype medfly in laboratory and field cage tests. CONCLUSION: The high competitiveness of the transgenic lines and the achieved 100% embryonic lethality causing reproductive sterility without the need of irradiation can improve the efficacy of operational medfly SIT programs.