Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Identification and synthesis of semiochemicals from arthropod

Identifizierung und Synthese von Semiochemikalien aus Arthropoden

Auteur  : Chinta, Satya Prabhakar

Université de soutenance : Universität Carolo-Wilhelmina zu Braunschweig

Grade : Doktors der Naturwissenschaften (Dr. rer. nat.) 2010

Résumé
Semiochemicals play an important role in nature to modify behavior of individuals and thus shape the environment. In the present study four projects have been performed. Two projects emphasize on spiders, since not much focus has been reported on their communication behavior so far. Additionally, pheromones in some agricultural important arthropods need to be identified to overcome pests. Although much research that has been performed till date suggesting the widespread use of pheromones by spiders, not many have been structurally elucidated. The first project (chapter 3) concentrates on identification and synthesis of volatile extracts obtained from spider Argiope bruennichi along with bioactivity and chiral resolution studies. Recent advances in spider semiochemicals suggested that cuticular lipid profiles of spiders are similar to that of arthropods with little variation compared to insects. To get a deeper perception, male and female cuticular lipid profiles of the spider Argyrodes elevatus were analyzed in this research group[32] and synthesis performed.[33] Stereoselective synthesis targeting these long chain methyl branched esters to identify the exact configuration and comparisons with the natural compounds is the major goal of this project (chapter 4). The beetle Pachnoda interrupta, commonly called sorghum chafer, is a serious pest in the northern part of Ethiopia. Currently, there are no efficient control methods, except by mass trapping which would possibly reduce the population. Invention of some attractive lures might also prove beneficiary. Observations regarding the mating and aggregation behavior of the beetle in the field led us to suspect the existence of a pheromone which might possibly be responsible for this behavior. Analyzing the natural extracts from this beetle to figure out the possible attractants and to synthesize novel unsaturated hydrocarbons was the main intention of the project (chapter 5). Females of the winter moth Operophtera brumata emit a long chain poly unsaturated hydrocarbon (3Z,6Z,9Z)-1,3,6,9 nonadecatetraene as pheromone.[34] In order to resolve the biosynthetic pathway of this pheromone, attempts were made to synthesize isotopically labeled polyunsaturated fatty acid and fatty acid methyl esters
Introduction of stable heavy isotopes at any one end of the fatty acid chain and following investigations of the biosynthesis are the main intentions of this project (chapter 6)

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