TRIBOLIUM CASTANEUM (COLEOPTERA: TENEBRIONIDAE): EPICUTICULAR HYDROCARBONS AND A VOLATILE SEX PHEROMONE

GIROTTI JUAN R; MIJAILOVSKI SERGIO J; FUSE CECILIA B; JUÁREZ M.PATRICIA

Buenos Aires

Congreso; II Reunión conjunta de Sociedades de Biociencias.; 2017

Sociedad de Biociencias

The red flour beetle, Tribolium castaneum is a model organismfor insect development studies and a major stored product pest ofagriculture relevance. Insect surface is covered by hydrocarbons(HC) protecting them against chemical and physical aggression.The aim of this study was to identify and quantify the changes inthe epicuticular HC of T. castaneum through the development cycle, and to investigate the potential presence of a volatile sex pheromone. Component identification was performed by capillary gaschromatography (CGC) coupled to mass spectrometry (MS); adultvolatiles were extracted by solid phase microextraction (SPME) andanalyzed by CGC-MS. The HC amounts increased significantly fromlarva to adult. In immature stages, saturated HC are predominant,with chain lengths of 23 to 43 carbons. A significantly different HCphenotype was observed in the adult stage, with large amounts ofbranched chains of 27 to 31. In this study, small amounts of a novel aldehyde component were detected in males. Females, but notmales, were attracted to this chemical in bioassays. The MS analysis revealed a molecular weight of 210, a twelve carbon unsaturated backbone and at least one methyl-branch. Further analysesare ongoing to fully determine the structure. Here we show that T.castaneum HC undergo substantive changes through development,suggesting a precise regulation of the biosynthetic enzymes. Thecomplex metabolic pathway for both, the HCs and the sex pheromone probably takes place in different tissues and is initiated bythe action of two fatty acid synthases (FASs), with different affinityto incorporate methyl branches in the elongating chain. Five genesencoding FAS were identified in the T. castaneum genome. Studieswill be started in order to identify the FAS genes responsible for HCand pheromone synthesis. This knowledge will help understand HCbiosynthesis and its regulation. The discovery of a sex pheromoneis of interest in pest control.Keywords: Tribolium, Hydrocarbons, Pheromone, CGC-MS.