Acta Entomologica Sinica ›› 2021, Vol. 64 ›› Issue (5): 597-604.doi: 10.16380/j.kcxb.2021.05.006

• RESEARCH PAPERS • Previous Articles     Next Articles

Effects of oviposition intensity on the reproductive phenotype of parthenogenetic Trichogramma dendrolimi (Hymenoptera: Trichogrammatidae) induced by Wolbachia

 HUO Liang-Xiao1,#, LI Yuan-Yuan1,#, ZHANG Dan2, YU Qian1, NING Su-Fang1, ZHAO Xu1, ZHOU Jin-Cheng1,*, DONG Hui1,*   

  1.  (1. College of Plant Protection, Shenyang Agricultural University, Shenyang 110161, China; 2. Liaoning Agricultural Development Service Center, Shenyang 110034, China)
  • Online:2021-05-20 Published:2021-05-31

Abstract: 【Aim】 Trichogramma dendrolimi is an important egg parasitoid applied in the biological control of lepidopteran pests. This study aims to investigate the effects of oviposition intensity on the titer of Wolbachia in parthenogenetic T. dendrolimi and its parthenogenetic reproductive phenotype induced by Wolbachia. 【Methods】 The effects of different oviposition intensities of females of T. dendrolimi in three treatment groups (supplied with host eggs for only 1 h per day, supplied with host eggs for 24 h every other day and supplied with host eggs all the time) on its biological parameters including the daily proportion of offspring males, daily fecundity, cumulative proportion of offspring males, and cumulative fecundity within 7 d were investigated in the laboratory. Besides, the Wolbachia titers (the copy numbers of wsp) in T. dendrolimi females without oviposition experience (the control), supplied with host eggs for only 1 h per day and supplied with host eggs all the time were detected by fluorescence quantitative real-time PCR. 【Results】 The cumulative proportion of offspring males of T. dendrolimi females supplied with host eggs all the time was significantly higher than that of females supplied with host eggs for only 1 h per day, but was not significantly different from that of females supplied with host eggs for 24 h every other day. The daily proportions of offspring males in the three treatment groups significantly increased with wasp age, and the increase rate was the highest in the treatment group of females supplied with host eggs all the time. The cumulative fecundity of T. dendrolimi females supplied with host eggs all the time was significantly higher than those of females supplied with host eggs for only 1 h per day and females supplied with host eggs for 24 h every other day. The daily fecundity in the three treatment groups significantly decreased with wasp age, but the decrease rate was the highest in the treatment group of females supplied with host eggs all the time. The Wolbachia titer in T. dendrolimi females without oviposition experience was significantly higher than that in T. dendrolimi females supplied with host eggs all the time, but showed no significant difference from that in T. dendrolimi females supplied with host eggs for only 1 h per day. 【Conclusion】 The results suggest that both Wolbachia titer and parthenogenetic phenotype of T. dendrolimi decline when its females can deposit their eggs without limitation. Limiting time for oviposition will be helpful to maintain Wolbachia titer and parthenogenetic phenotype. The results provide references for understanding the interaction between Wolbachia and host Trichogramma and the application of thelytokous parthenogenetic T. dendrolimi for controlling pest insects.

Key words: Wolbachia, Trichogramma dendrolimi, thelytokous parthenogenesis, oviposition intensity, fecundity