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Identifier 000429866
Title Προσδιορισμός και χαρακτηρισμός σημειοχημικών ουσιών του Drosophila suzukii για την ανάπτυξη ολοκληρωμένης στρατηγικής διαχείρισής του στην Ελλάδα
Alternative Title Determination of semiochemical compounds of Drosophila suzukii for development integrated pest management strategies in Greece
Author Μπελενιώτη, Μαρία Γ
Thesis advisor Χανιωτάκης, Νικόλαος
Reviewer Κατερινόπουλος, Χαράλαμπος
Βόντας, Ιωάννης
Βασιλικογιαννάκης, Γεώργιος
Γανωτάκης, Δημήτριος
Ροδιτάκης, Εμμανουήλ
Σπύρος, Απόστολος
Abstract The economy of many countries and specifically countries of Mediterranean is based in agricultural production. Insect pests are a big hazard, since they are responsible for the damage of many crops. Drosophila suzukii Matsumura (Diptera: Drosophilidae) is a relatively new pest for Europe, affecting a wide variety of small and stone fruits. Infection by D. suzukii causes fruit to be unsuitable for distribution and consumption resulting in significant economic damage. In order to control this pest and limit the economic damage on fruit crops, farmers usually resort to the use of organophosphate, spinosyn and/or pyrethroid insecticides. Unfortunately, the insecticide efficacy on D. suzukii is limited and the impact on biodiversity, ecosystem, food and water ecosystems is devastating. Nowadays, biological control methods play a crucial role for the Integrated Pest Management (IPM) with the ability to suppress pest population below economic thresholds rather than only providing a temporary control based on broad range agrochemicals. For this reason, the search for alternative insect management strategies of D. suzukii in food crops is of vital importance. The cuticle of insects is covered with a layer of wax that consists of lipids, a class of compounds that includes alcohols, fatty acids, acylglycerols and hydrocarbons. Cuticular hydrocarbons (CHCs) are found at all life stages of insects and their production can be affected by several factors such as reproductive status, sex, age, maturation, food, temperature, social experience and photoperiod. One of the main roles of these compounds is to serve as means of communication and signaling, providing both inter-and intraspecific information including aggregation, mating, alarm, aggression and recognition. In this thesis a method coupling gas chromatography with electron ionization mass spectrometry was developed for a better structural identification of CHCs of D. suzukii. In addition to the known CHCs reported in previous studies, three new compounds, nonadecane, 2-methyleicosane and 2-methylheneicosane, was observed. We evaluate the effect of solvent extraction time on the amount of D. suzukii CHCs. Extraction time can affect the detection as well as the relative amount of substances in both male and female flies. Specifically, it was shown that the increase of the extraction time had a profound effect on the amount and type of CHCs determined in both sexes of D. suzukii. Increasing the extraction time, we were also able to detect new compounds in the fly, which subsequently were used to evaluate their role on insect’s behavior. Based on the quantitative results obtained, we further evaluated the biological role of two compounds, dodecane and 9-pentacosene. It was found that the D. suzukii adults are repulsed when exposed to dodecane (C12) acting as alarm pheromone. On the other hand, 9-pentacosene (9-C25) seems to enhance mating behavior of D. suzukii males acting as sex pheromone Furthermore, the study of the effect of age and sex in CHCs production showed that there are prominent changes in CHC profiles in function of age-related maturation and less prominent changes in function of sex. Specifically, we concluded that D. suzukii has a sexually monomorphic CHC. Both sexes at age of 1 day produced compounds in high abundance which they have long carbon chains (C25-C33), while at the age of 2 and 25 days insects produced CHCs with short carbon chains (C19-C25). The results of bioassays demonstrate that 9- heneicosene (9-C21) positively regulated the aggregation. We investigate the aggressive behaviour of D. suzukii. Inter-male and inter-female aggression was determined ethologically consisting of several behaviour patterns. Two hours starvation period increase locomotor activity of flies, promoting increased aggressive behaviour. Number of male encounters was higher in flies held in isolation than in those that had been reared with siblings whereas in case of females, only those that were isolated exhibited increased aggression. Females and males D. suzukii that were 4-day-old were more aggressive. In addition it is found that on the 3rd hour after the beginning of photoperiod, regardless of age, both genders rise to high intensity aggression patterns. Also the effect of socialization in CHC profile of insect was study. It is observed that non-socialization resulted increased amounts of 7-tricosene (7-C23). Evaluation of biological role of 7-C23 showed that it is a compound that increases the aggressive behaviour of male D. suzukii. Our findings offer potential new routes for IPM strategies. Many potential IPM strategies such as attract-and-kill, mass trapping and mating disruption rely on chemical communication used by insects. We propose that 9-C21, C12, 9-C25 and 7-C23 CHCs could be part of an IPM for D. suzukii
Language Greek
Subject 7-tricosene
D. suzukii
Extraction time
Ολοκληρωμένη φυτοπροστασία
Χρόνοι εκχύλισης
Issue date 2020-06-10
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Doctoral theses
  Type of Work--Doctoral theses
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