Temperature and Photoperiodic response of Diapause induction in Aphidius gifuensis Ashmead

Author of the article:Li Yuyan, Zhang Lisheng, Chen Hongyin, Wang Wei,

Author's Workplace：Key Laboratory of Integrated Pest Management in crops, Ministry of Agriculture, Institute of Plant Protection, Chinese Academy of Agricultural Sciences

Key Words：Diapause, Aphidius gifuensis, Temperature, Photoperiod

Abstract：Aphidius gifuensis Ashmead is an important solitary endoparasitoid of aphid, which play a significant role as biocontrol agent in biological control. The research on diapause of A. gifuensis not only could help us to realize the developmental mechanisms of natural enemy insects deeply, but also could prolong the product shelf-life and enhance the efficiency of pest biocontrol. The diapause induction response of temperature and photoperiod on A. gifuensis was studied with a method of temperature gradient variation and a photoperiodic response curve method in this research. The results indicated that A. gifuensis was characterized by winter diapause, and it diapaused as mature larvae. Low temperature and short day length were the two key factors in diapause induction of A. gifuensis. More aphid parasitoids can enter into diapause if the two factors interacted. Diapause was induced successfully under the temperature below 12 °C and a short day length (L8: D16). At 8 °C, up to 54.35% of A. gifuensis entered diapause. Under a long day length of L14: D10, high temperature was unable to induce A. gifuensis into diapause and the diapause rate was only 1.79% at 10 °C. Diapause rate was 50.7% under conditions of low-temperature (10 ºC) and a short day length (L8: D16). However, the diapause rate decreased significantly when the photoperiod was 14h and 6h. The effects of photoperiod on diapause induction were not significant at 25 ºC. Long day, medium or short day lengths were unable to induce diapause of A. gifuensis. Temperature and photoperiod were both affected diapause induction of A. gifuensis significantly. Temperature played a greater role than photoperiod on diapause induction, and the interaction between them was very significant (P<0.01).