Identification of the Aggregation Pheromone of the Date Palm Root Borer Oryctes agamemnon

Abstract

Laboratory and field investigations aimed to characterize the chemical communication system of the date palm pest Oryctes agamemnon. Live males or extracts of male effluvia attracted conspecifics in an olfactometer, whereas female effluvia attracted only males. Volatile emissions from adults feeding on sugarcane were sampled and analysed by gas chromatography (GC) and GC/mass spectrometry (GC/MS). Males emitted a blend of 1) ethyl 4-methyloctanoate, 2) 4-methyloctanoic acid, 3) 4-methyloctanyl acetate, and 4) 4-methyloctanol in variable ratio. Single sensillum recordings demonstrated that compounds 1, 2, and 3 are detected by specific olfactory receptor neurons. Olfactometric experiments showed that compounds 1 and 3 attract both sexes of O. agamemnon, but females are more attracted by compound 1 and males by compound 3. Compound 2 was more attractive for females, especially virgin ones. Field experiments confirmed that compound 1 and compound 2 attracted O. agamemnon of both sexes and showed synergy with palm odors. No clear activity of compound 3 was observed. A mix of compounds 1 and 2 with date palm core odor was significantly the most attractive, and captured more females than males. The male aggregation pheromone of O. agamemnon appears therefore to be based on a mixture in contrast to previously identified Oryctes pheromones. Our results provide the basis for developing mass trapping to control this pest.

Attraction of Adults of Cyclocephala lunulata and Cyclocephala barrerai (Coleoptera: Scarabaeoidea: Melolonthidae) towards Bacteria Volatiles Isolated from Their Genital Chambers

“…The attraction of both male and female individuals of C. lunulata towards several of the VOCsB indicates that these are aggregation attractants [ 62 , 63 ]. Aggregation has been cited for species from Dynastinae; although the production of these chemical substances has been primarily associated with males [ 37 , 39 , 64 , 65 , 66 , 67 , 68 , 69 ], there are reports of female beetles emitting this type of pheromone as well [ 70 , 71 ]. In this study, the females of Cyclocephala produced the compounds, possibly with the assistance of bacteria associated with their genital chamber, and this coincides with other studies reporting that VOCsB act as aggregation attractants for their insect hosts [ 35 , 36 ].…”

Draft Genome of the Scarab BeetleOryctes borbonicuson La Réunion Island

“…Previous work has shown that Pristionchus species and P. pacificus strains show specificity in their response to the pheromones of their beetle hosts ( Hong and Sommer 2006 ; McGaughran et al 2013 ; Cinkornpumin et al 2014 ). Nonhydroxylated fatty acid ester derivatives pheromones were identified in four species from the Oryctes genus, that all are coconut pest species ( Said et al 2015 ). If the same kind of molecules would be active as pheromones in O. borbonicus , some Cytochrome P450s may be involved in their inactivation, as they do for molecules from other chemical classes in the scarab beetle Phyllopertha diversa (Maïbèche-Cosne et al 2004).…”

Identification of Components of the Aggregation Pheromone of the Guam Strain of Coconut Rhinoceros Beetle, Oryctes rhinoceros, and Determination of Stereochemistry

“…Ethyl 4-methyloctanoate is produced by males of all the other species of Oryctes reported to date: O. agamemnon (Said et al 2015), O. elegans (Rochat et al 2004), and O. monoceros (Allou et al 2006;Gries et al 1994) and attractive to both female and male conspecifics. In all species investigated, the corresponding acid was also reported to be produced, and in O. elegans it was the predominant component and more attractive to conspecifics than the ethyl ester, particularly when combined with date palm volatiles (Rochat et al 2004).…”