Plant secondary compounds are able to affect the activities of some insect pheromones,but the underlying mechanisms remain unclear. In this study,we use quantum chemistry theory to assay whether the two plant volatiles,engenol and citronellyl acetate that are ubiquitous in floral nectar and pollen,react with homovanillyl alcohol (HVA),a volatile component of the Apis mellifera bee queen pheromone. Geometry optimization,transition state searching and frequency calculations by Gaussian 09 show that engenol and HVA can readily react with OH,respectively. The two reaction intermediates can induce a polymerization reaction through the radical-radical pathway (the energy barrier and rate constant for the pathway are 0. 613077 kcal /mol and 9. 559953 * 10~(11) cm~3 /molecule /s,respectively),but unlikely through the radical-molecule pathway (the energy barrier and rate constant for the pathway are 31. 792769 kcal /mol and 4. 268854 * 10~(-13) cm~3 /molecule /s,respectively). Similarly,after citronellyl acetate and HVA react with OH,respectively,their reaction productions would polymerize through radicalradical pathway (the energy barrier and rate constant for the pathway are 2. 086469 kcal /mol are and 2. 328216 * 10~(11) cm~3 /molecule /s,respectively),but unlikely through the radical-molecule pathway (the energy barrier and rate constant for the pathway are 25. 881002 kcal /mol and 1. 513828 *10~(-8) cm~3 /molecule /s, respectively). Our study suggests that abundant OH radical due to climate change may make honeybee queen pheromone less resistant against plant volatiles,thereby disturbing chemical communication in honeybees.