| Anoplophora glabripennis (Motschulsky) is a major polyphagous wood-boring beetle in China that caused great losses to the forest of China. Its primary host species include Acer (maple), Populus (poplar), Salix (willow) and Ulums (elm) and is reported to feed on more than 20 genus host trees. A large number of research projects have focused on this beetle in last 20 years, but host-selection mechanism of adults is unclear. For this reason, this paper makes deep research on host-selection mechanism of adults with types and morphological characteristics of sensilla, chemical ecology, enzymology, and behavior of animal. The main results were as follows:1. Behavioral responses of adults A. glabripennis to volatiles emanating from different host trees:Behavioral responses of adults A. glabripennis which emerged from Salix matsudana f.lobato-glandulosa (SM), Poplus. nigra L.var. thevestina (PN), P. simonii×P. pyramidalis cv'opera 8277'(PS)and P. alba var. pyramidalis(PA) to volatiles of these hosts twigs and preferred ash leaf maples twigs(Acer negundo) were measured with a Y-tube olfactometer in the laboratory.With clear air as control, adults A. glabripennis emerging from four host tree species had an obvious orientation response to volatiles emanating from their natal host twigs (P < 0.05), while volatiles emanating from twigs by PA had some repellence to the adults emerging from other three tree species. In addition, the ash leaf maples twigs attracted all adults emerging from each tree species, and the attraction of volatiles emanating from ash leaf maples twigs to female adults was not significant (P > 0.05). With volatiles of ash leaf maples as control, the attraction of volatiles emanating from natal hosts and ash leaf maples to adults emerging from four different tree species had no significant difference. Therefore, A. glabripennis could recognize volatiles emanating from their host plants without existence of preferred host trees. Otherwise, A. glabripennis had no taxis to volatiles emanating from their natal host trees with existence of preferred host trees. 2. Learning behavior of adult A. glabripennis:The learning behavior of A.glabripennis provided A. negundo and P. alba var. pyramidalis (PA) as food for different days was studied using Y-tube olfactometer . After adults were provide ash leaf maple as food for 1 day, response rate of adults to volatiles emanating from ash leaf maple twigs had obviously increased and the attraction of volatiles emanating from A. negundo to adult a significant difference(P < 0.05). Adults were provided ash leaf maple as food for 2 days, and response rate of adults to volatiles of ash leaf maple increased continuously. As for the adults that were providing ash leaf maple as food for 3and 5days, response rate of adults to volatiles of ash leaf maple maintained up to 70%. It was that demonstrated adults feeding on ash leaf maple induced their preference. Volatiles of PA had a strong repellent effect to adults that were not fed PA (P < 0.05). After adults were provide PA as food for 1 day, the repellent of volatiles emanating from PA twigs to female adults was not significant (P > 0.05). Adults were provided PA as food for 2 days, response rate of adults to volatiles of PA reached to 60%. Adults that were provided PA as food for 3 days were significantly attracted to volatiles emanating from PA twigs (P < 0.05). Adults that were provided PA as food for 5 days, response rate of adults to volatiles of PA maintained the same level with those adults were provided PA as food for 3 days. It demonstrated adults that were feeding on PA induced their habituation. Our experiments demonstrated that feeding experience of adult A.glabripennis was changed response to odour. That is to say, adults A.glabripennis have the ability of learning.3. Behavior of host-selection of A. glabripennis in mixed forest:A mixed forest plot with five tree species of 5-year-old were planted in the cage in the field and arranged in a Latin-square design. The tree species were SM, PN, PS, PA and AN. Whether adult A. glabripenni emerging from these five species had"memeory"effect to its natal host tree were researched and explored. Through observing and analyzing inhabiting, feeding, mating, and oviposition of beetles on these trees, the percentage and frequency of observations on AN was higher than on other tree species. Adult A.glabripenni had no showing"memory"effect to their larval host tree species. This is probably due to adults feeding on ash leaf maple induced their preference and the"memory"effect of adult to their larval host was enshrouded.If there was no AN, the percentage or frequency of observations of adult on SM was higher than on other 3 tree species by observing and analyzing inhabiting, feeding, mating, and oviposition of beetles on these trees. As for oviposition of beetles on these trees, it had no a role. On the whole, SM trees showed strong"attractant"effects if there was no AN.4. Components and activity of digestive enzymes in A. glabripennisLarvae feeding on five different tree species, pupae in four different trees, and adults emerging from five host species were selected as experimental materials. The components and activity of digestive enzymes extracted from these materials of A. glabripennis were analyzed and detected .The results revealed that 8 digestive enzymes were detected in larvae and adult A. glabripennis: amylase, pectinase, invertase, maltase, hemicellulase, tryptase, pepsin, and lipase. In addition, it was reported there were endo-β-1,4-glucanase (Cx-cellulase), exdo-β-1,4-glucanase (C1-cellulase) andβ-1,4-glucosidase (β-glycosidase) in larvae and adult. So the larvae and adult A. glabripennis have integrated digestive enzymes. The activity of amylase, pectinase, invertase, maltase, hemicellulase, tryptase and pepsin was not detected in pupae. The activity of lipase in pupae was detected, but its activity was very low. The order of each digestive enzymes activity of larvae of five different tree species was not consisted with the adult emerging from the same tree species. The digestive enzymes activities of adults had no directly correlation with larvae. From larvae to adults by holometamorphosis, the digestive enzymes activities of larvae had no directly effected on adults.5. Ultra-structure and types of sensilla on the head of A. glabripennisUltra-structure, number and distribution of sensilla on the antennae, labial palpi and maxillary palpi of A. glabripennis were observed with an environmental scanning electron microscope. The results indicated that there were 5 types and 13 kinds of sensilla on antennae, including of 5 kinds of sensilla chaeticas, 2 kinds of sensilla trichodeas, 4 kinds of sensilla basiconcas, 1 kind of sensilla campullacea, and 1 kind of finer sensilla.There were 6 types and 17 kinds of sensilla on labial palpi and maxillary palpi, including of 7 kinds of sensilla chaeticas, 2 kinds of sensilla trichodeas, 3 kinds of sensilla basiconcas, 2 kinds of sensilla styloconica, 2 kinds of sensilla coeloclnicas, and 1 kind of sensilla placoclea. The potential functions of sensilla were dicussed on the basis of its distribution, shape characters as well as correlative references.
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