Effects of rose pollen and nectar on body size and ovarian development of Frankliniella occidentalis (Thysanoptera: Thripidae).

Western flower thrips, Frankliniella occidentalis (Pergande), is an omnivorous pest feeding on plant tissues and floral resources, including pollen and nectar, and can consume mite eggs. Its growth and reproduction are strongly influenced by diet quality. Compared with rose petals alone, a standardized whole-flower diet contains reproductive organs and therefore provides additional floral resources. In this study, a standardized whole-flower diet, rose petals, and kidney bean leaves as a host-plant control were used to investigate whether differences in floral resource availability affect thrips development and reproduction. After three consecutive generations, multiple parameters were measured, including body size (length and width), ovarian development (ovariole length and number of mature eggs), juvenile hormone (JH) content, vitellogenin (Vg) content, and expression of Kr-h1, br, JHEH, and Vg. Relative to the kidney bean leaf control, thrips on the whole-flower diet exhibited significantly greater body length and width, whereas those on rose petals had shorter length and similar width. Reproductive traits varied with adult age, and females reared on the whole-flower diet generally had longer ovarioles than those reared on rose petals and significantly greater numbers of mature eggs than the kidney bean leaf control at each sampled time point from Days 2 to 9 after adult emergence. JH and Vg contents and gene expression also varied significantly with diet, adult age, and their interaction. Together, these findings indicate that floral resources in the whole-flower diet enhance the growth and reproductive development of F. occidentalis and may favor its performance on flowering host plants.