Interação entre Rhynchophorus palmarum (L., 1758) (coleoptera: curculionidae) e o parasitoide Billaea rhynchophorae (Blanchard, 1937) (Diptera: tachinidae)

Abstract

Rhynchophorus palmarum (L., 1758) (Coleoptera: Curculionidae) is the main pest of arecaceae in the Neotropical region. It occurs in several Brazilian states and attacks, in addition to palm trees, several cultures of economic importance. In coconut Cocos nucifera L. and oil palm Elaeis guineensis Jacq., it causes direct and indirect damage, leading to reduced productivity. The most used control methods are cultural, behavioral and biological, although none of them is efficient, economical and ecologically viable. Parasitoid flies of the genus Billaea Robineau-Desvoidy, 1830 (Diptera: Tachinidae) have been used to control pests of large crops in Latin America and, in Brazil, the natural parasitism of R. palmarum by Billaea spp. in oil palm plantations is recorded, but there are no studies on the chemical ecology of these natural enemies. Thus, the present work aimed to identify Volatile Organic Compounds (VOCs) involved in the pest-parasitoid interaction, as well as the cuticular compounds of Billaea rhynchophorae (Blanchard, 1937). The pest and the parasitoid were collected in oil palm plantations in the state of Bahia, Brazil, transported to the Natural Resources Research Laboratory (LPqRN) and keptin in BOD. The volatiles from R. palmarum larvae and oil palm stem were obtained through the dynamic headspace technique, and cuticular extractions of different parts of B. rhynchophorae were also performed using solvent. The headspace and cuticular extracts were analyzed and the compounds were identified by Gas Chromatography coupled to the Flame Ionization Detector (GC-FID) and Gas Chromatography coupled to Mass Spectrometry (GC-MS). Chemical analyzes revealed the presence of 17 compounds in the headspace extracts and seven in the cuticular extracts. In the electroantenography bioassays, three compounds present in the headspace were active for B. rhynchophorae females. The compounds identified in the cuticular extracts are similar among the analyzed parts and belong to the hydrocarbon class. Keywords: Arecaceae, Biological Control, Volatile Organic Compounds, Chemical Ecology.