Effect of sex ratio on the reproductive potentials and longevity of the beet webworm, Loxostege sticticalis
Author of the article:LI Min-Min1** CHENG Yun-Xia1 XIAO Yong-Hong1, 2 LUO Li-Zhi1***JIANG Xing-Fu1 ZHANG Lei1
Author's Workplace： 1. State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of AgriculturalSciences, Beijing 100193, China; 2. College of Life Sciences, Jinggangshan University, Jiangxi 343009, China
Key Words：Loxostege sticticalis, sex ratio, mating capacity, lifetime fecundity, longevity, population dynamics
Abstract： [Objectives] To understand the effects of sex ratio on the reproduction of Loxostege sticticalis, thereby improving our understanding of its biology and ability to forecast outbreaks of this species. [Methods] Reproductive parameters were studied under different sex ratios (♀︰♂=1︰3; 1︰2; 1︰1; 2︰1; 3︰1) under laboratory conditions (temperature (22±1)℃, RH70%±5%, photoperiod 16 L︰ 8 D). [Results] Sex ratio had an obvious impact on L. sticticalis reproductive parameters. The results show that the pre-oviposition period of female L. sticticalis increased with increasing sex ratio. The period of first oviposition in the 1︰1 group was the highest among the five sex ratio groups. Female reproductive parameters such as mating time, egg production and number of hatchlings did not vary much among the different sex ratio groups, but those of males increased rapidly with increasing sex ratio. Both male and female longevity were significantly lower at a sex ratio of 3︰1. Males’ maximum mating time and number of offspring were about twice those of females at sex ratios of 1︰3 and 3︰1. [Conclusion] Sex ratio had little influence on the reproductive parameters of female adults compared to those of males; a 1︰3 sex ratio appeared to significantly reduce males’ mating ability and reproductive capacity. Analysis of adults’ mating potential and fecundity suggests that a sex ratio of 2︰1 is optimal with regard to the most efficient use of resources, whereas a sex ratio of 1︰1 is the best for population growth.