.Adult Tessaratoma papillosa (Drury) (Hemiptera: Pentatomidae) secreted volatiles from metathoracic glands (MTG). Behavior and olfactory responses of adult bugs to their MTG secretions were tested using a Y-tube olfactometer and an electroantennogram (EAG). The results indicated that males were obviously attracted by female secretions and repelled by male secretions. Secretions of adult males elicited the greatest response of male antennae, whereas the lower response of male antennae to MTG secretions of adult females was recorded. The four compounds, (E)-2-octenal, undecane, dodecane and tridecane were tested for the EAG activity and behavior response with male adults at different concentrations. In EAG assays, the antenna of male T. papillosa showed the highest sensitivity to (E)-2-octenal (10 μL /μL) and the second highest sensitivity to undecane (10 μL /μL), but a similar sensitivity to other stimuli. Unlike EAG results, males were attractive to (E)-2-octenal (10-2 and 10-1 μL /μL) and tridecane (10 μL /μL), and repelled by (E)-2-octenal (10-3, 1, 10 and 102 μL /μL) and tridecane (10-1 μL /μL) in the Y-tube olfactometer. Our data suggested that (E)-2-octenal and tridecane may be part of a complex pheromone system in T. papillosa.