Courtship behavior and identification of a sex pheromone in Ibalia leucospoides (Hymenoptera: Ibaliidae), a larval parasitoid of Sirex noctilio (Hymenoptera: Siricidae)

• Published in: PeerJ (San Francisco, CA) Vol. 9; p. e12266
• Main Authors: Faal, Hajar, Silk, Peter J, Mayo, Peter D, Teale, Stephen A
• Format: Journal Article
• Language: English
• Published: United States PeerJ. Ltd 04.11.2021; PeerJ, Inc; PeerJ Inc
• Subjects: Agricultural Science; Alkanes; Analysis; Animal Behavior; Animal reproduction; Antennae; Bath products; Behavior; Biological control; Courtship; Courtship behavior; Cuticular hydrocarbon; Cuticular hydrocarbons; Ecology; Electroantennograms; Entomology; Females; Foraging behavior; Gas chromatography; Hydrocarbons; Hymenoptera; Ibalia leucospoides; Ibaliidae; Males; Mass spectrometry; Mass spectroscopy; Nitrogen; Parasitoid; Parasitology; Pests; Pheromones; Rhythms; Sex pheromone; Sirex noctilio; Siricidae; Wire netting; New York; United States > US; Southern Hemisphere; Sex pheromone; Ibaliidae; Parasitoid; Courtship behavior; Cuticular hydrocarbon
• ISSN: 2167-8359; 2167-8359
• DOI: 10.7717/peerj.12266

(Hymenoptera: Ibaliidae) is a larval parasitoid that has been widely introduced as a biological control agent for the invasive woodwasp (Hymenoptera: Siricidae) in the Southern Hemisphere. In this study, the courtship behavior and identificaion of sex pheromones are described for under laboratory conditions. For courtship behavior, both sexes were observed in a wire mesh observation cylinder (75 cm length ×10 cm diameter) for 15 minutes. The female body washes were analyzed using Gas Chromatography- Electroantennographic Detection (GC-EAD). Then the EAD-active compounds were tentatively identified using GC-Mass Spectrometry (GC-MS) and examined in olfactometer assays. The courtship behavior included rhythmic lateral movements, mounting, head-nodding cycles in males, and wing-fanning in females. GC-EAD analysis of female body washes with male antennae revealed seven compounds which elicited antennal responses, four of which are straight-chain alkanes (C , C , C , and C ). The identities of these alkanes were confirmed by matching the retention times, mass spectra, and male antennal activity to those of commercially obtained chemicals. In olfactometer assays, a blend of the four straight-chain alkanes was attractive to males, and there was no response to blends that lacked any of these four compounds. Female body wash was no more attractive than the four-component blend. The ratios of EAD-active components differ between hydrocarbon profiles from males and females. This study is the first investigation of cuticular hydrocarbons in the family Ibaliidae. It provides evidence that the ubiquitous alkanes (C , C , C , and C ) in sex-specific ratios attract males.