| Summary: | <i>Thrips hawaiiensis</i> is a common thrips pest of various plant flowers with host preference. Plant volatiles provide important information for host-searching in insects. We examined the behavioral responses of <i>T. hawaiiensis</i> adults to the floral volatiles of <i>Gardenia jasminoides</i> Ellis, <i>Gerbera jamesonii</i> Bolus, <i>Paeonia lactiflora</i> Pallas, and <i>Rosa chinensis</i> Jacq. in a Y-tube olfactometer. <i>T. hawaiiensis</i> adults showed significantly different preferences to these four-flower plants, with the ranking of <i>G. jasminoides</i> > <i>G.</i> <i>jamesonii</i> > <i>P. lactiflora</i> ≥ <i>R. chinensis</i>. Further, 29 components were identified in the volatile profiles of <i>G. jasminoides</i>, and (Z)-3-hexenyl tiglate (14.38 %), linalool (27.45 %), and (E3,E7)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (24.67 %) were the most abundant. Six-arm olfactometer bioassays showed that <i>T. hawaiiensis</i> had significant positive responses to (Z)-3-hexenyl tiglate, linalool, and (E3,E7)-4,8,12-trimethyltrideca-1,3,7,11-tetraene tested at various concentrations, with the most attractive ones being 10<sup>−3</sup> μL/μL, 10<sup>−2</sup> μL/μL and 100 μg/μL for each compound, respectively. In pairing of these three compounds at their optimal concentrations, <i>T. hawaiiensis</i> showed the preference ranking of (Z)-3-hexenyl tiglate > linalool > (E3,E7)-4,8,12-trimethyltrideca-1,3,7,11-tetraene. Large numbers of <i>T. hawaiiensis</i> have been observed on <i>G. jasminoides</i> flowers in the field, which might be caused by the high attraction of this pest to <i>G. jasminoides</i> floral volatiles shown in the present study. Our findings shed light on the olfactory cues routing host plant searching behavior in <i>T. hawaiiensis</i>, providing important information on how <i>T. hawaiiensis</i> targets particular host plants. The high attractiveness of the main compounds (e.g., linalool, (E3,E7)-4,8,12-trimethyltrideca-1,3,7,11-tetraene, particular (Z)-3-hexenyl tiglate) identified from volatiles of <i>G. jasminoides</i> flowers may be exploited further to develop novel monitoring and control tools (e.g., lure and kill strategies) against this flower-inhabiting thrips pest.
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