## 1 Introduction  
_Thrips hawaiiensis_ Morgan (Thysanoptera: Thripidae) is a common flower-dwelling thrips pest of various horticultural plant species [1, 2]. Native to the Oriental and Pacific regions, _T. hawaiiensis_is nowadays distributed in Asia, America, Africa, Australia, and Europe due to the expansion of international trade in fresh flowers, fruits, and vegetables [3; 4; 5; 6]. In the field, _T. hawaiiensis_ can attack a large number of plant species such as banana, mango, citrus, apple, tobacco, coffee, tea, horticultural plants and vegetables [6; 7; 8]. Therefore, it has become an important agricultural pest globally.  
Chemical insecticides have always been the primary tool for _T. hawaiiensis_ control, especially the high number of specific treatments applied on banana and mango crops [9; 10; 11]. _T. hawaiiensis_ showed the potential to rapidly develop resistance to insecticides (e.g., spinetorn) under laboratory selection [9; 10]. Early detection of thrips is important for growers to decide when best to apply chemical insecticides or when to alter them, which would help to limit the frequency of insecticide applications, delaying the development of insecticide-resistance. Understanding the host-location behavior in thrips would be helpful for the development of monitoring tools for their early detection.  
The color, shape and volatiles associated with different plant species were considered to provide vital cues for thrips and help them to search and locate more suitable host plants [12; 13; 14; 15; 16]. Many studies have evaluated the olfactory responses of thrips, e.g., the western flower thrips _Frankliniella occidentalis_ Pergande (Thysanoptera: Thripidae), indicating that both floral volatiles and non-flaval odors were attractive to this pest [14; 16; 17; 18]. Further, it was reported that rose volatile compounds allowed the design of new control strategies for western flower thrips [19]. So far little information has been mentioned on the behavioral responses of _T. hawaiiensis_ to plant volatiles.  
As a polyphagous flower-inhabiting thrips in China, _T. hawaiiensis_ is always the dominant thrips pest on many banana and mango orchards during their flowering stages [9; 10; 11; 20]. In addition, _T. hawaiiensis_ varies in its population size on different flower host plants and vegetable crops at the flowering stage and particularly showed a preference for _Gardenia jasminoides_ Ellis (Gentianales: Rubiaceae) flowers [21; 22]. These results indicated that host plant flowers had a great attractiveness to _T. hawaiiensis_. To contribute to the knowledge on the role of volatile compounds in the host-searching behavior of _T. hawaiensis_, the olfactory responses of adult insects to the odors of different flower plants including _G. jasminoides_, _Gerbera jamesonii_ Bolus (Campanulates: Asteraceae), _Paeonia lactiflora_ Pallas (Ranales: Ranunculaceae), and _Rosa chinensis_ Jacq. (Rosales: Rosaceae) and to the main components identified from the preferred flower plant (_G. jasminoides_) were studied. These results may also help in developing new monitoring tools and other control options, which could be implemented in integrated pest management (IPM) strategies against _T. hawaiensis_.