Mictis stink bug volatiles
Chromatogram data (GC-MS) for stink bug secretions analyses, taken from species common in China. (i) GC-MS chromatogram for several species obtained in local parks; (ii) GC-MS chromatogram for a Mictis fuscipes female secretions analysis; (ii) GC-MS chromatogram of a Mictis fuscipes male secretions analysis; (iii) GC-MS chromatogram of the secretion mimicking the main components in secretions of Mictis spp using synthetic standards (hexyl hexanoate, hexanoic acid, hexyl acetate, hexyl butyrate, and eugenol); (iv) High-speed videos of the behaviors of fire ants attacking the stink bugs, illustrating how the secretions of Mictis spp prove fatal to the ants.
Steps to reproduce
Adult stinkbugs were collected from green areas at Shixing County, Shaoguan City, and Guangzhou city, Guangdong Province. Those included Pentatomidae species Dalpada oculata, Chalcopis glandulosa, Tessaratoma papillosa; Coreidae species Mictis serina, Mictis fuscipes, Physomerus grossipes, Acanthocoris scaber, Notobitus meleagris, Homoeocerus unipunctatus, Physomerus centralis; Dinidridae species Coridius chinensis. Polygyne (i.e. bearing multiple queens) colonies of the imported fire ant S. invicta were collected from a public park at Tianhe District, Guangzhou City, Guangdong Province. Chromatograms: Stink bug adults were mechanically stimulated using forceps, leading to ejections from their metathoracic scent gland to be collected into a capillary tube (inner diameter = 0.9 mm) and dissolved into 1 mL of hexane in a separate glass vial. Some grains of sodium sulfate were added to the extract solution and stirred for 2 minutes to remove any remaining water. This extract was filtered through a 0.45-μm pore size PTFE membrane and was finally concentrated under a constant nitrogen gas flow to approximately 100 μL 20. Following storage at -20 ℃, 2 μL of the extract were injected under splitless mode into a gas chromatography spectrometer (GC-MS, Agilent 8890 - 5977B) set with a capillary column HP-5ms (30 m × 0.32 mm × 0.25 μm), using helium as the carrier gas at a flow rate 1 mL/min (99.99% high-purity); the injection port temperature was set at 250 ℃; ion source voltage set to EI 70 eV; column interface temperature held at 280 ℃; oven temperature ramp started with a 2 minutes hold at 50 ℃ followed by increasing 20 ℃/min up to 260 ℃, and a final hold for 2 minutes. Chromatograms were obtained from Shimadzu Real Time Analyser, and can be opened with OpenChrome software. Video: One adult stink bug was confined among ten selected Solenopsis invicta fire ant media workers inside a 9-cm diameter glass petri dish. This bioassay was subsequently repeated exposing different species of stink bugs to the fire ants to determine whether M. fuscipes indeed proves more lethal against the ants than other local stink bug species, when replicated under similar conditions.
Fundação de Amparo à Pesquisa do Estado de Goiás
Science and Technology Planning Project of Guangdong Province