Host preference of Thrips hawaiiensis for different ornamental plants

Thrips hawaiiensis is a common thrips pest that damages the flowers of various plants. The differing population sizes of T. hawaiiensis among host plants suggest its preference and performance vary among host plants. In this study, the host fitness of T. hawaiiensis for different flowers was assessed through field investigation. The behavioral responses of T. hawaiiensis to the color and volatiles of flowers eliciting different apparent fitness levels and their development and survival on the plants were also studied. Adults and larvae of T. hawaiiensis were found in the flowers of 21 species, which were classified into four fitness levels for this thrips species. T. hawaiiensis showed significantly different visual responses to the color and olfactory responses to the volatiles of four tested flowers (each representing one of the four fitness levels), with the rankings of visual preferences for Dianthus caryophyllus > Tulipa gesneriana > Hydrangea macrophylla > Rosa rugosa, and olfactory preferences for H. macrophylla ≥ T. gesneriana > D. caryophyllus > R. rugosa. Plant species had significant influences on the development and survival of T. hawaiiensis, with developmental times from egg to adult of 9.58 d, 9.92 d, 10.35 d and 10.75 d on H. macrophylla, T. gesneriana, D. caryophyllus and R. rugosa, respectively, and corresponding survival rates of 76.33%, 71.33%, 64.00% and 59.00%. In summary, this study shows that olfactory preferences were consistent with the field performance of T. hawaiiensis on the four flower plants tested. Further, fitness levels of host plant flowers are correlated with development rate and survivorship of T. hawaiiensis. Our study adds to the understanding of the mechanism of host selection by thrips and provides basic information to underpin the management of T. hawaiiensis on horticultural plants.