Abstract: 【Aim】 This study aims to clarify the relationship between fecundity and ovary development of Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). 【Methods】 The 1st instar nymphs, 2nd instar nymphs, prepupae, pupae, and the 1-day-old adults were subjected to 41℃ and 45℃ heat shock, respectively, for 2 h and the changes in their ovary development and relative contents of yolk protein were observed. 【Results】 The normal development of reproductive organs and embryos of F. occidentalis  were inhibited by heat exposure, which resulted in the reduction in the number of ovarian tubes and deformity of ovarian tubes and embryo. The yolk protein of F. occidentalis was identified as a phosphorylated and glycosylated lipoprotein, consisting of three subunits with the molecular weight of 116, 70 and 47 kDa, respectively, through electrophoresis and different dyeing methods. The yolk protein synthesis of F₀ generation adults was inhibited when nymphs and prepupae were exposed to high temperature, and the effect of high temperature on the relative content of yolk protein continued to F₁ generation whenthe 1st or 2nd instar nymphs were exposed to high temperature (45℃). 【Conclusion】 The effect of temperature on female fecundity of F. occidentalis is due to its influence on the development of reproductive organs and the synthesis of yolk protein. This study lays a foundation for the further research on yolk protein and vitellogenesis of F. occidentalis.

Key words: Frankliniella occidentalis, heat shock, ovary, yolk protein, fecundity