Research On Themogenesis And Volatile Organic Compoundsof Rhaphidophora Decursiva (Roxb.) Schott Inflorescence And The Interaction With Colocasiomyia Flies

Rhaphidophora decursiva belongs to Araceae,Rhaphidophora.Colocasiomyia belongs to Drosophilidae,Drosophilinae.It is the classic model creature that main pollinate to Araceae.In the mutualism relationship between the plant and its pollinators,Aroids and flies have always been the system that researchers focus on.There is a themogenesis phenomenon during the blossomtime due to the special floral character including the spathe and spadix.Themogenesis can create a shelter for the pollinators,and the heat energy will promote the release and distribution of the volatile organic compounds.With the dissemination,pollinators can be better attracted to pollinate them,so the pollination efficiency of the plant is improved.Plants and pollinators have benefited from each other thus they become an ideal system for researching mutuallybeneficial symbiosis.To understand the mutualistic stability in Interaction relationship between the two species of Colocasiomyia and Rhaphidophora decursiva in biology and chemical ecology,we investigated the biological characteristics of the genus Colocasiomyia and Rhaphidophora decursiva based on the field observation,and the benefits that each species obtains from their obligate nursery pollination mutualism.In this study,four-channel memory thermometers were used to continuously monitor the three parts of the inflorescence of Rhaphidophora decursiva and the environmental temperature for 120 hours;dynamic headspace adsorption-GC/MS and solid-phase microextraction and GC/MS were used for collecting and analyzing the inflorescence volatiles of the Rhaphidophora decursiva.A series of behaviours of Colocasiomyia flies were continuously observed and photographed.The results were as follows:1.The inflorescences didn't have the themogenesis before flowering.When the spathe first opened,the temperature accelerated at about 10 am,peaked around 12 noon,then began to decline,reached the lowest level in the early morning.The next day,the spathe spread out widely and the temperature continued to rise to the peak at noon.On the third day,generally the spathe fell down,and the inflorescence continues a themogenesis until the pollinators leave.2.An average of six compounds were detected for one inflorescence with dynamic headspace adsorption-gas chromatography mass spectrometry.The contents of 3-pentanone,?-farnesene,1-pentanol,and linalool were the highest.21 compounds were detected for one inflorescence with solid-phase microextraction-gas chromatography mass spectrometry,mostly were sesquiterpenoids.Among them,3-pentenone and E,E-?-farnesene had the highest contents(2.09% and 88.7% respectively),presumably the main substances to absorb pollinators.3.The Colocasiomyia fly is most frequently active from 10 am to 2 pm.The olfactory receptors of the antenna are used to sense the volatiles of the flowers until they are accurately located to find the most suitable host plant.Its entire life history strongly relies on host plants.Eggs grow and develop between inflorescences.Hatched larvae feed on spoiled inflorescences or infructescences.Adults take nectar,seek for mate,copulate,reproduce,and develop until the inflorescence matures and cracks and then the mature flies flew out,which also shows that there is an exact correspondence between the pupae's feather and the fruit ripens and dries.The study Fills the gap in the ecology of Monsteroideae and also provides a new scientific basis for the maintenance mechanism of the symbiotic relationship between the Araceae and pollinators.