Acta Entomologica Sinica ›› 2019, Vol. 62 ›› Issue (8): 979-986.doi: 10.16380/j.kcxb.2019.08.010

• RESEARCH PAPERS • Previous Articles     Next Articles

Changes in the cold hardiness of overwintering larvae of Histia rhodope (Lepidoptera: Zygaenidae)

YANG Hai-Bo, HU Zhen-Jie, DONG Jun-Feng, ZHU Pin-Hong, LI Ding-Xu*   

  1. (Forestry College, Henan University of Science and Technology, Luoyang, Henan 471000, China)
  • Online:2019-08-20 Published:2019-08-29

Abstract: 【Aim】 Histia rhodope is one of the major pests of Bischofia polycarpa. This study aims to investigate the cold hardiness of H. rhodope larvae and to provide a theoretical basis for exploring its cold resistance mechanisms. 【Methods】 The body weight, supercooling point (SCP), freezing point (FP) and contents of water, fat, total sugar and total protein in overwintering larvae of H. rhodope were measured at different overwintering stages (November 7, 2017, December 7, 2017, January 5, 2018, February 4, 2018, and March 5, 2018). 【Results】 There were significant differences in the SCP of H. rhodope larvae among the different overwintering months, and SCP showed a significant positive correlation with the ambient temperature (P<0.05). The lowest mean SCP (-15.26℃) occurred in January, and the highest (-13.30℃) occurred in March. The variation tendency of FP was consistent with that of SCP. The fresh weight and fat content decreased gradually during the overwintering period, and there was no correlation between the SCP and the fresh weight and fat content (P>0.05). The supercooling capacity increased as the free water content decreased, while reduced as the free water content increased. However, the change trend of bound water content was opposite to that of the free water content. The total sugar content in November was the highest (14.95 μg/mg), which was significantly higher than that in March (5.07 μg/mg). The total protein content increased first and then decreased during overwintering, and reached the highest value in January (23.666 μg/mg), which was significantly higher than that in November (16.69 μg/mg). 【Conclusion】 The cold hardiness of overwintering larvae of H. rhodope increases gradually with the decrease of ambient temperature and then weakens with the increase of ambient temperature. Proteins may be the important cold-resistant substance in H. rhodope.

Key words: Histia rhodope, overwintering larva, cold hardiness, supercooling point, biochemical substances