Population Source of Third-Generation Oriental Armyworm in Jilin, China, Determined by Entomology Radar, Trajectory Analysis, and Mitochondrial COI Sequences

Abstract

The armyworm, Mythimna separata (Walker) (Lepidoptera: Noctuidae), is an important polyphagous pest with a strong migratory ability. Recently, third-generation larvae have become an increasingly serious pest threat in Jilin Province of northeast China. To investigate the population source of this species, scanning entomological radar observations and insect mitochondrial cytochrome oxidase I (COI) genes were used in this study. Five main results were found: (1) The peak period in captured second-generation moths was from mid to late July. The temperature and wind speeds were optimum for the moths to have migrated. Strong southwesterly winds occurred during the peak migration period. (2) Radar observations indicated that most of the moths’ migration took place at a height of 600 m, often in a dense layer which formed at heights of 350–800 m. (3) Analyses of adult ovarian development and larval haplotypes showed third-generation larvae were progeny of both locally produced progeny and immigrant moths. (4) Based on our back-tracking and haplotype analyses, immigration led to an outbreak originated in the same source area to the southwest. (5) Emigration of second-generation moths was confirmed by both radar observation and mtDNA analysis. Forward trajectories indicated that the moths were capable of immigrating far from their overwintering range. These results are useful for improving the forecasting systems of this insect pest species.

Destinations of third-generation Mythimna separata (Lepidoptera: Noctuidae) moths in Jilin and its effects on population genetic diversity

“…Jilin's spring moth (first-generation moth) is considered an immigrant pest (Chen et al 1989). In our previous study, we utilized the scanning entomological radar and molecular marker to prove that the summer moth (second-generation moth) is considered a mixed (emerged, migrants, and retained) population (Sun et al 2022). In this study, analysis of ovarian development revealed that the degree of ovarian development and mating rates were low.…”

“…4. H33, combined with other haplotype data, were used in our previous study to determine the population source of the third-generation M. separata in Jilin Province (Sun et al 2022). By comparison, this study provided novel findings (The same as Fig.…”

“…A total of ten geographical populations were obtained, including four populations from the third generation in 2016 and six populations from the second generation in 2017 (Table 2). To determine the population source of the third-generation M. separata in Jilin Province, the 2017 samples combined with other molecular data were used in our previous study (Sun et al 2022). This study brought has reported new findings in the estimation of migration destinations of the third-generation moths, by comparison.…”

“…Based on the data from 2015 to 2019, the forward trajectory simulations, therefore, suggest that the moths dispersed over a wide area. There were endpoint differences among the To determine the population source of the third-generation M. separata in Jilin Province, the 2017 samples combined with other molecular data were used in our previous study (Sun et al 2022). This study brought has reported new findings in the estimation of migration destinations of the third-generation moths, by comparison 4).…”