## 2 Materials and Methods  
### Collection and Identification of Volatiles Released by PaP  
Volatiles were collected from the branches and leaves of 5-year-old PaP trees in situ (N: 40.341528; E: 106.927669). Trees in the field were divided into three groups, and each group had six trees. One group of trees was kept as a control. The trunk of each tree in the second group had ten notch grooves cut into it using a clean sterilized knife 1.2-1.7 m above the ground; this mechanical damage simulated ALB oviposition notch grooves. In the third group of trees, each trunk was caged with a nylon mesh (20 mesh) at 1.2-1.7 m above the ground, in which one adult male and three adult female ALB were introduced. After 10 notch grooves were gnawed on each tree by the females, the cages and the beetles were removed, and volatile collection began. Branches (30 cm length) were enclosed in a polyethylene (PE) bag (35 cm \(\times\) 45 cm; Glad, ClCo., Ltd., Guangzhou, China), and a pumping system QC-1B (Beijing Labor Protection Scientific Research Institute, Beijing, China) was used to collect the released volatiles. Charcoal-filtered air at a flow rate of 450 mL/min was pumped into the PE bag, and the volatiles carried through a glass adsorption tube (10 cm length, 5 mm inner diameter) containing 200 mg of Porapak Q (80-100 mesh, Waters Corporation, Milford, MA, USA). Teflon tubes were used for all connections (Figure S1). Immediately after collection, volatiles were eluted from the trap tube with 1000 \(\mu\)L of dichloromethane and then concentrated down to 200 \(\mu\)L under a gentle flow of nitrogen at 0 \({}^{\circ}\)C and stored at \(-\)20 \({}^{\circ}\)C. Six replicate samples per treatment were used, each from a different tree. Empty bags were also considered as blank controls to enable possible contaminants to be identified and removed from analysis. Collections were made from 8:00 to 17:00 h, the active period of ALB adults.  
Volatiles were identified using a GC capillary column (TG-WAX, 30 m \(\times\) 0.25 mm \(\times\) 0.25 \(\mu\)m) in an Agilent 78908-7000C GC-MSD system (Agilent Technologies, Santa Clara, CA, USA). The injection volume of the samples was 1 \(\mu\)L. The injector port was at 240 \({}^{\circ}\)C, and the heating program was 40 \({}^{\circ}\)C for 1 min, an 8 \({}^{\circ}\)C/min increase to 180 \({}^{\circ}\)C, maintained for 1 min, a 20 \({}^{\circ}\)C/min increase to 200 \({}^{\circ}\)C, and maintained for 2 min. EI: 70 eV; MSD transmission line: 230 \({}^{\circ}\)C. The scanning mass range was 35-550 aum with a 0.2 s/scan. Primary identification was achieved by comparing the volatile compounds' mass spectra with those from the NIST14 libraries. For bioactive compounds, commercial synthetic compounds were obtained to verify the retention time, the entire mass spectra, and the Kovats retention index, and the results were compared with those from the SDBS website at [[https://sdbs.db.aist.go.jp](https://sdbs.db.aist.go.jp)]([https://sdbs.db.aist.go.jp](https://sdbs.db.aist.go.jp)); (accessed on 15 July 2022). The quantities of both Z3H and Z3 HA were calculated by standard solution curves already established in our previous studies [3].