| Dioryctria abietella and D. sylvestrella are close relative species in the same genus, which both endanger cones of Pinus koraiensis concomitantly, but their biological and ecological behaviors are quite different. This study investigated the interactions between the host Pinus koraiensis chemical defense and physiological adaptation of these two Dioryctria species. Explored the way for improveing the healthy level of forest and control these two species by the application of chemical ecology. Results of the research were listed below:1. Behavioral response of D.abietella, D. sylvestrella adults to infrared radiationForaging animals use diverse cues to locate resources. Common foraging cues have visual, auditory, olfactory, tactile or gustatory characteristics. Here, we show a foraging herbivore using infrared radiation from living plants as a host-finding cue. We present data revealing that during the day, the trapped rates of infrared radiation for two Dioryctria virgin female was significantly higher than the repellency rate. In the night, the trapped rates of the infrared radiation for virgin and mated female of two species Dioryctria were significantly higher than repellency rate.2. Effect of volatiles from health and herbivore-damaged red pine day or night on the behavioral selection of D.abietella, D. sylvestrella and parasitoid Macrocentrus sp D.abietella and D. sylvestrella is an important borer pest to cone of P koraiensis, D. sylvestrella not only borer cone but also tips, and these two specises were concomitantly endangered cones. For investigating which specises was responed for larvea induction sensitivity of host pine. We tested the day-night behavioral response of the moth and parasitoid (Macrocentrus sp. is the larva parasitoid of D. sylvestrella) to cone, tip and branch picked on healthy or larvae damaged red pines were assayed by Y tube. The profiles of volatiles released from the cone, tip and branch in day and night were analyzed using GC-MS. Bioassay suggested that D.abietella and D. sylvestrella virgin female moths, mated female moths and male moths tended to healthy cone and tip volatiles released at night. Virgin and mated female of D. sylvestrella also tended to damaged cone at night. We proposed that D. sylvestrella may be the sensitive specises for fed P koraiensis called negative defense of host plant. Male and female parasitic wasps tended to damaged cone and tip volatiles released in day. The volatile components and contents had significant differences between healthy and pest damaged pine released in day and night. The variations of terpenes released from different parts of healthy and pest damaged pine presented diel rhythm. These volatiles attracted parasitic wasps in day, and were more effective on the moth oviposition behavior at night. For the regulating of the behavior of the moth and parasitoid wasps, bioactive single or combined terpenes volatile need to be further identified.3. Electroantennogram and behavioral responses of D.abietella, D. sylvestrella and parasitoid Macrocentrus sp to volatiles of P. koraiensisThe males, virgin and mated females of D. abietella displayed a significantly electrophysiological response to the other 7 volatile compounds compared with controls, except R-α-pinene and camphene. Then, compared with controls, except R-α-pinene the virgin and mated femals of D. sylvestrella displayed a significantly electrophysiological response to the other 8 volatile compounds; while the males displayed a significantly response to the other 6 volatile compounds except R-a-pinene, myrcene and D-limonene.The olfactory response ratio for males, virgin and mated females of D. abietella and D. sylvestrella to 9 volatile compounds of the host plant were more 75%. The olfactory responses of the adults varied with the different volatile compounds and its concentrations. The males, virgin and mated females of D. abietella and D. sylvestrella were attracted by S-a-pinene, ocimene and 3-carene, and then the mated females of D. sylvestrella repulsed by the high-concentration ocimene. Females of D. abietella and males of D. sylvestrella were repulsed by phellandrene. Camphene volatilized form the feeding cones significantly increased at night. By the behavioral mensuration, the feeding cones attracted female D. sylvestrella and then repelled female D. abietella. So, camphene would play an important role in the relationship between Dioryctria behavior response and larvae induction host sensitivity. D-limonene was only volatilized form lateral branches of P. koraiensis, and repelled the females of D. abietella and D. sylvestrella. This repelled function would be an important reason of Dioryctria evading the lateral branchs of P. koraiensis.The olfactory response ratio for males, virgin and mated females of D. abietella and D. sylvestrella to 9 volatile compounds of the host plant were more 75%. The olfactory responses of the adults varied with the different volatile compounds and its concentrations. The males, virgin and mated females of D. abietella and D. sylvestrella were attracted by S-a-pinene, ocimene and 3-carene, and then the mated females of D. sylvestrella repulsed the high-concentration ocimene. Camphene volatilized form the feeding cones significantly increased at night. By the behavioral mensuration, the feeding cones attracted female D. sylvestrella and then repelled female D. abietella. So, camphene would play an important role in the relationship between Dioryctria behavior response and larvae induction host sensitivity. D-limonene was only volatilized form lateral branches of P. koraiensis, and repelled the females of D. abietella and D. sylvestrella. This repelled function would be an important reason of Dioryctria evading the lateral branchs of P. koraiensis.Female parasitoids presented higher EAG value on 7 volatiles except camphene than that on controls (P<0.05), and attracted by R-a-pinene, S-a-pinene, ocimene and 3-carene. The EAG value of Male parasitoids on R-α-pinene, S-α-pinene was higher than on control (P<0.05), and they were attracted by these kinds of volatile. R-α-pinene may be potentially useful as attractants for parasitoids, Phellandrene as repellents controled Dioryctria and no significant effect onparasitoids.4. Different survival strategies in two Dioryctria species larvae adapt to chemical defense of host plant P. koraiensisFor investigating the interactions between the host P. koraiensis chemical defense and physiological adaptation of these two Dioryctria species larvae, we analyzed the larvae midgut detoxication enzymes and protective enzymes activities in 1,3,5th instars, and the corresponding period defense enzymes, protease inhibitors and phenolic acid in health, fed pine cones or tip branches.The results showed that PAL, PPO, POD, SOD, CAT TI, CI and phenolic acid in health pines were changed with cones or tips growth development stage. These two Dioryctria larvae feeding caused significant different defense compounds compared with healthy cones or tips, which were influenced by various instars Dioryctria larvae. Detoxication enzymes and protective enzymes in these two Dioryctria species lived by different survival strategies were quite different. D. abietella feed on cone through larval stage, their detoxication enzymes, GST, CarE, MFO in midgut, increased. with larval instars, and were significantly higher than D. sylvestrella. GST, CarE, MFO of D. sylvestrella were significantly changed when different instars larvae transferred between cones and tips. There were no significant different with SOD and CT activities in D. abietella and D. sylvestrella midgus presented the same trend, whether transferred feeding was not the key words for these two protective enzymes. The higher PO and POD in D. sylvestrella midguts, compared with D. abietella, protect them to avoid the threat of the transfer process. According to the results mentioned above, it is clear that the physiological detoxification was the predominant survival strategies for D. abietella larvae to adapt to chemical defense of host plant, whereas D. sylvestrella larvae make themselves survived not only by carrying out the physiological detoxification but also altering feeding behaviors, especially for the expense in the feeding scope.5. Exogenous jasmonates system induced chemical defense of P. koraiensisThe activities of SOD, CAT, POD, PPO and PAL increased significantly in cones and tips induced by different concentration exogenous jasmonates atomizing sprayed. There is no significant different between systemic or spotted exogenous jasmonates atomizing sprayed induced defense enzymes. Defense enzymes induced by exogenous jasmone treatment were more similar with larvae feeding than Methyl jasmonate.The activities of TI in cones and tips were separately significant increased in 1-60 d and 1-30d treated by different concentration exogenous jasmonates. The activities of CI in cones and tips were separately significant increased in 1-120 d and 30-120d, and systemic exogenous jasmonates sprayed induced CI was significant higher than spotted sprayed. TI and CI induced by exogenous jasmone treatment were more similar with larvae feeding than Methyl jasmonate.We detected coumaric acid, phenylacetic acid, ferulic acid, salicylic acid and cinnamic acid,5 phenolic acids in health cones, and coumaric acid, phenylacetic acid, benzoic acid, salicylic Acid and cinnamic acid,5 phenolic acids in health the main tips. The number of phenolic acid in cone and tips were same, but these were different kinds of phenolic acid in cone and tips. Larvae feeding caused protocatechuic acid and carbolic acid in cone, and carbolic acid in tips. Except coumaric acid decreased in cone, other several kinds of phenolic acids in cones and the main tips were significantly increased., Exogenous jasmone induced more kinds of phenolic acids compared with Methyl jasmonate. Except protocatechuic acid, chlorogenic acid, syringic acid, phenolic acids were higher than herbivore-induced, the content and induction time of other kinds of phenolic acids treated by jasmone and feeding were more similar.10 mmol·1-1 systemic exogenous jasmonates atomizing sprayed induced phenolic acids, protease inhibitors and defense enzyme were already significantly higher or similar with herbivore-induced. This concentration jasmone spraying was effective dose enhanced resistance of host pine against shoot borer larvae feeding.We studied the law of chemical defense of pine, the strength of induced chemical defence, the release of volatiles and infrared radiation, combined with the bio-ecological characteristics and physiological adaptation characteristics of D. abietella and D. sylvestrella, revealed the relationship between the two kinds of species emergence and volatiles of P. koraiensis circadian rhythm, negative defense, infrared radiation, and chemical defense, figured out synergetic occurrence mechanism between these two species and pine. |
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