Population establishment of Frankliniella occidentalis (Thysanoptera: Thripidae) offspring under parental arrhenotocous parthenogenesis reproduction

The reproductive mode of parthenogenesis is critical for Frankliniella occidentalis (Thysanoptera: Thripidae) invasive species. Studies have shown that the survival of female thrips was significantly higher than that of male thrips at high temperature (45 ℃, 2 h). In order to explore the possibility of population establishment of western flower thrips by parthenogenesis under high temperature conditions, female adult thrips were exposed to 45 ℃ for 2 h and then their offspring (F₁ generation) back-crossed with parental or “uncertain parental” female thrips. The life table was established to describe the population development of offspring after back-crossing (F₂ generation). The results indicated that the above two modes of generation of female copulated with F₁ male offspring both produced fertile offsprings. The sex ratio of the F₂ generation from parental female adult (female︰male = 1.05︰1) was lower than the sex ratio of the F₂ generation from “uncertain parental” female adults (female︰male = 1.55︰1). In addition, the F₂ generation from parental female had lower average female fecundity (F, 44.25 eggs per female), lower intrinsic rate of increase (r_m, 0.133 9), longer average developmental duration, longer adult pre-oviposition period (APOP, 3.13 d), longer total pre-oviposition period (TPOP, 17.19 d) and longer average generation duration (23.32 d) than the F₂ generation from “uncertain parental” female adults (P < 0.05; F of 62.25 eggs per female, r_m of 0.146 8, APOP of 2.85 d, TPOP of 14.45 d and longer generation duration of 20.49 d). However, no significant difference was noted in the finite rate of increase (P > 0.05). The results indicated that F. occidentalis established populations within a short time by arrhenotocous parthenogenesis and had strong resistance to high temperatures and reproductive capacity, which laid the basis for successful invasion. A single high temperature model was not ideal for the control of F. occidentalis in case of host plant without serious injuries. This suggested that multiple control modes were better. Future studies should investigate and discuss effective control modes of F. occidentalis.