Abstract:

Objective: This study analyzed and screened the active substances in the volatiles of Sabina przewalskii that attract Megastigmus sabinae. By verifying their attractiveness through field experiments, this study aims to provide scientific basis for protecting S. przewalskii forest land, improving the quality of S. przewalskii seeds and regeneration. At the same time, it is also to provide a basis for exploring the communication mechanism between M. sabinae and its host plants. Method: A Y-tube olfactometer was used to determine the attractiveness and repellency of 7 volatiles to M. sabinae. Monomers and their concentrations with optimal attractiveness were selected and their combination was used for indoor attraction experiments. The compound formula with superior attractiveness was identified and then used in conjunction with traps to conduct field trapping technique research. Result: 1) In the monomer experiment, at a concentration of 10 μg?μL^?1, there were five compounds that exhibited significantly higher attraction rates than the repellent rates for female M. sabinae. These compounds were sabinene, 2,4-dimethy lacet ophenone, α-terpineol, alpha-pinene oxide, and myrcene. At a concentration of 1 μg?μL^?1, the attraction rates of alpha-pinene oxide and myrcene were significantly higher than the repellent rates. For male adults, at a concentration of 10 μg?μL^?1, the attraction rates of 3-carene and myrcene were significantly higher than the repellent rates. At a concentration of 1 μg?μL^?1, the attraction rate of 2,4-dimethylacetophenone was significantly higher than the repellent rate, while the attraction rates of α-terpineol and alpha-pinene oxide were significantly higher than the repellent rates. 2) In the compound experiment, formula G had the highest attraction rate for female M. sabinae（57%, P<0.05）, followed by formulas B and A. Formula I had the highest repellent rate for M. sabinae. 3) In the field trapping experiment, traps with compound formulas G, A and B as lure cores had significantly higher trapping volumes than the control group. Formula G had the highest trapping volume, accounting for 34.1% of the total number of trapped insects. Formulas A and B accounted for 27.3% and 25.7% of the total number of trapped insects, respectively. Among traps of three different colors, yellow traps had the best attraction effect, trapping a total of 234 adult insects, accounting for 56.5% of the total number of trapped insects. Blue and green traps trapped 82 and 98 insects, respectively. The boat-shaped trap trapped 209 insects while the triangular trap trapped 205 insects. There was no significant difference in trapping volume between these two types of traps (P>0.05). Conclusion: All three formulas demonstrates an attractive effect in the field, with formula G exhibiting the greatest attraction effect on M. sabinae and showing potential as a lure core for traps. The most effective results are achieved when used in conjunction with yellow traps. Thus, in practical applications, formula G can be used as a core paired with a yellow trap to monitor the population of M. sabinae in the forest.

Key words: Sabina przewalskii, Megastigmus sabinae, host volatiles, compound formula, behavioral responses, trapping technology