The Mechanism Of Chemical Communication Between Elm And Ambrostoma Quadriimpressum

In this paper, infochemicals from the plants were first analyzed and identified by the headspace sampling method. Volatiles from a year-old elm seedlings including intact and induced by adult and larvae Ambrostoma quadriimpressum of different population was identified. Comparing with volatiles from host and non-host in the field, and extract from elm's phloem, the release rhythm of volatile and the main factors of affecting the release of volatile were analysis. And then infochemicals from A. quadriimpressum by extraction, including the cuticular of larvae, the hindgut pre-and post feed and the feces produced by adults and larvaes. Combined with compounds from plants, chemical communication and link between the two were analysis. At last the bioassay in the lab and field was finished, so as to choosing suitable chemicals that lured adult A. quadriimpressum.Herbivore-induced volatiles increased both quantitative and qualitative compared to the undamaged intact elm, the volatiles induced by 10 adult A. quadriimpressum increased 6 chemicals which were benzyl benzoate, tmtt, (+)-longifolene, benzoic acid, butyl ester, methyl salicylate and 2-heptanol. The volatiles induced by 40 adults A. quadriimpressum increased 10 chemicals which were anisole, cis-3-hexenyl acetate,1-undecene, undecanal, methyl salicylate, linalool, caryophyllene, naphthalene,1,2-dimethyl-and tmtt. The volatiles induced by 20 larvaes A. quadriimpressum increased 12 chemicals which were 2,4,6-tris(1,1-dimethylethyl) phenol, tmtt, cis-Nerolidol, (+)-longifolene, caryophyllene, naphthalene, 1,2,3-trimethyl-4-propenyl-, (E)-, benzoic acid butyl ester, butanedioic acid dibutyl ester, methyl salicylate, linalool,2-heptanol and benzaldehyde. The volatiles induced by 40 larvaes A. quadriimpressum increased 11 chemicals which were anisole, benzaldehyde, cis-3-hexenyl acetate,1-undecene, methyl salicylate, linalool, undecanal, butylated hydroxytoluene, tmtt, heptadecane and benzyl benzoate. Some herbivore-induced volatile components were released immediately, such as green leaf odor, cis-3-hexenyl acetate released within 1h after 40 adults and 40 larvae induced. Release quantity reached the max when elm was damaged after 8-9h for most volatiles, whereas minority was reached the max when elm was damaged in the third day. Release of volatile for Ulmus pumila in the field followed the regulations that release quantity increased gradually in the morning, and reach the maximum at noon, and gradually reduced in the afternoon, there is an outbreak in day and night that is the time 19:00-20:00. Compared with volatiles in the lab, volatiles in the field increased 2-heptanol, anisole, benzaldehyde, (3-caryophyllene, cis-3-hexenyl acetate and cis-β-ocimene. Chemicals in the phloem inceased pentanal-2-methy, cis-2-peten-l-ol, hexanal 1,3-dimethyl benzene, methyl-pentylketo, myrcene, y-terpinene, naphthalene, decahydro-2,6-dimethyl-, naphthalene, decahydro-2,3- dimethyl-,α-humulene, globule, octadecane, nonadecane, n-eicosane and n-heneicosane, butβ-caryophyllene, cis-3-hexenyl acetate, linalool, methyl salicylate,1-tridecene, cis-nerolidol and tmtt from volatiles were not found in the phloem. There were 13 chemicals were in accordance with volatiles from elm.There are 26 chemicals from the cuticular of larvae A. quadriimpressum which were benzyl butyl ether, cis-2-peten-l-ol, n-octane, hexanal, benzene,1,2-dimethyl-, myrcene, benzeneacetaldehyde, phenyl acetate, methyl benzoate, naphthalene, decahydro-2,6-dimethyl-, naphthalene, decahydro-2,3-dimethyl-,1-methyl naphthalene, tetradecane, hexadecen-1-ol, trans-9-, heptadecane,1,2-benzenedicarboxylic acid, diundecyl ester, nonadecane, tetracontane, 3,5,24-trimethyl-, dodecane,2,6,10-trimethyl-, E-2-tetradecen-l-ol,1,2-benzenedicarboxylic acid, diundecyl ester, citronellylacetone, tetradecane,2,6,10-trimethyl-, dotriacontane,1-hexadecanol,2-methyl-,13-methyl heptacosane. Quality and quantity of infochemicals from 1st instar larvae is low, meanwhile quality and quantity of infochemicals from 4th instar larvae was the highest among each star, and had significant difference. The chemicals from the hindgut of female and male A. quadriimpressum changed pre-and post feed. For females cis-2-peten-1-ol, cyclohexane,1,4-dimethyl-, cis-, (-)-β-pinene, limonene, naphthalene, naphthalene, decahydro-1,5-dimethyl-, tetradecane,2,6,10-trimethyl-,1,2-benzenedicarboxylic acid, butyl 8-methylnonyl ester, dotriacontane, vitamin E,13-methylheptacosane were increased after feed, meanwhile for males, n-octane, styrene, a-thujene, camphene,3-carene, benzene, 1-ethynyl-4-methyl-, naphthalene, acenaphthylene,9,10-ethanoanthracene,9,10-dihydro-11,12-diacetyl-, vitamin E and dotriacontane were increased after feed. Some of these compounds were according with volatiles from elm, such as cis-2-peten-l-ol, (-)-β-pinene, limonene, dotriacontane and tetradecane,2,6,10-trimethyl. The compounds in the feces produced by adults were much than by larvaes,12 compounds which were limonene, cis-β-ocimene,α-pinene, phenyl acetate, linalool, methyl salicylate,α-farnesene,δ-cadinene, tmtt, nerolidol, n-hexadecane, heptadecane were according with volatiles from elm, moreover benzene,1,2-dimethyl-,α-pinene, limonene,1-heptatriacotanol, dotriacontane, vitamin E also were founding the hindgut of A. quadriimpressum.In this paper,13 compounds were chosen to conduct the bioassay in the lab and field. Experiments using the Y-tube olfactometer indicated that beetle-damaged elm seedlings were more attractive to additional beetles during the first 24 h of damage as compared with intact elm seedlings. Volatiles from feeding-damaged trees play important roles in attracting A. quadriimpressum. Electrophysiological and behavioral responses of male and female beetles to 13 semiochemical compounds from elm were investigated to determine their potential ecological functions prior to more detailed field studies. Electroantennograms (EAGs), EAG dose-response curves and Y-tube olfactometer bioassays using synthetic compounds revealed that females had a stronger response to linalool, a-farnesene, dibutyl phthalate, indole and cis-3-hexen-l-ol than to other compounds; males had a stronger response toγ-terpinene, a-farnesene and P-caryophyllene than to other compounds. EAG responses to linalool at doses of 0.1,10 and 100μg were significantly different between females and males. The results in the field were generally consistent with the results in the lab. But the quantity of A. quadriimpressum in the trap was less due to many factors. These factors could provide important information when synthetic attractants are evaluated as baits for controlling adult A. quadriimpressum.