Timing of oviposition and mating in chlorantraniliprole-resistantPlutella xylostella (L.)
Author of the article:WANG Hai-Hui1, 2** ZHANG Jin-Ming2*** TU Qin2 LIU Gui-Ying2 Lü Yao-Bin1, 2***
Author's Workplace：1. College of Environment and Life Sciences, Hangzhou Normal University, Hangzhou 310036, China; 2. State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy ofAgricultural Sciences, Hangzhou 310021, China
Key Words： Plutella xylostella, chlorantraniliprole, resistant strain, oviposition location, mating and oviposition rhythms
Abstract：
[Objectives] To clarify whether differences in the timing of mating and oviposition, or oviposition preferences, exist between a chlorantraniliprole-resistant, and a laboratory, strain of Plutella xylostella , and whether differences in these behaviors are conducive to the evolution of insecticide resistance. [Methods] The timing of mating and oviposition in a laboratory (LAB) and two chlorantraniliprole-resistant strains (a medium resistant (MR) strain and a high resistant (HR) strain), were compared under laboratory conditions. [Results] (1) The resistant strains preferred to lay eggs on the middle underside of the leaves of cabbages and laid more eggs than the LAB strain on leaves L1-L5. Resistant strains laid a greater proportion of eggs on lower, than on higher, leaves than the LAB strain, but there was no significant difference in the proportions of eggs laid by the different strains on growing points (GP), stem (S) and petioles (P). (2) Most mating activity in all three strains took place between 00:00-06:00, but the timing of the second mating peak differed between strains; that of the LAB (29.40%) and MR strains (25.91%) occurring between 18:00-24:00, whereas that of the HR strain (28.67%) occurred from 12:00-18:00. (3) The percentages of eggs laid in the daytime by the LAB, MR and HR strains were 39.49%, 37.57% and 42.67%, respectively, but the proportion of eggs laid in the daytime by the HR-strain was significantly higher. All three strains were similar in the timing of oviposition; oviposition periods could be ranked in descending order of egg abundance from, 00:00-06:00, 12:00-18:00, 18:00-24:00 to 06:00-12:00. [Conclusion] Resistant strains prefer to lay their eggs on the mid-underside of lower cabbage leaves. There were some differences in the timing of mating and oviposition between the resistant and LAB strains. Furthermore, the peak mating periods of the HR and LAB strain were partly staggered. These behavioral differences facilitate the vertical transmission of resistance genes, but further research is required to determine whether they affect the speed at which resistance to chlorantraniliprole develops in P. xylostella.