Population genetics unveils large‐scale migration dynamics and population turnover of Spodoptera exigua

Abstract

BACKGROUND Migration is a widespread phenomenon among many insect species, including herbivorous crop pests. At present, scant information exists on the long‐range migration of the polyphagous armyworm, Spodoptera exigua and its underlying climatic determinants (i.e. East Asian or South Asian monsoon circulation). In this study, we employed a population genetics approach to delineate S. exigua migration patterns across multiple Asian countries. RESULTS Using mitochondrial cytochrome I (COI) and microsatellite markers, low‐to‐moderate levels of genetic diversity were detected among 101 S. exigua populations collected across China, Pakistan and Vietnam. Haplotype diversity and nucleotide diversity did not differ between years. Two spatially explicit genetic clusters were detected, an eastern and a western clade, with the former comprising populations in the East Asia monsoon area. No genetic differentiation was recorded among armyworm populations in the year‐round breeding area, nor among those of the overwintering and nonoverwintering areas. Five of the most widespread mitochondrial haplotypes reflected the extensive gene flow across at a large spatial scale. CONCLUSION Low‐to‐moderate levels of genetic diversity were observed, and evidence was found for genetic clustering in certain geographical areas. Accordingly, our unique insights into S. exigua population genetics and spatiotemporal migration dynamics help to guide applied ecological studies, ecological intensification schemes or (area‐wide) pest management campaigns in China and abroad. © 2021 Society of Chemical Industry.

The blowfly Chrysomya latifrons inhabits fragmented rainforests, but shows no population structure

“…Strongly dispersing species with long-distance seasonal migration patterns generally tend to show low population structure over broad geographic ranges (Endersby et al 2007 ; Pfeiler and Markow 2017 ; Wang et al 2021 ), further supporting the possibility that large numbers of Ch. latifrons undertake long migrations during the spring and summer.…”

Population dynamics of migrant wheat aphids in China’s main wheat production region and their interactions with bacterial symbionts

“…To date, the economical searchlight trap and high effective radar are widely employed to investigate insect migrations. However, the searchlight trap is mostly used to uncover the migrations of lepidopterous pests with large bodies ( Guo et al., 2020 ; Zhou et al., 2021 ; Guo et al., 2022 ; Wang et al., 2022b ), and the commonly used centimeter-wave vertical-looking radar is unsuitable for monitoring small insects, such as aphids, and a more expensive radar with a shorter wavelength is required ( Chapman et al., 2003 ; Chapman et al., 2004 ; Feng et al., 2009 ). Suction traps have been used to monitor the aerial movement of aphids since 1964 ( Macaulay et al., 1988 ), which probably filled the gap in the investigation of aphid migrations.…”

Analysis of Thaumatotibia leucotreta (Lepidoptera; Tortricidae: Olethreutinae) mitochondrial genomes reveal opportunistic host range expansion towards rose

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