Tracking invasions of a destructive defoliator, the gypsy moth (Erebidae: Lymantria dispar): Population structure, origin of intercepted specimens, and Asian introgression into North America

Abstract

Genetic data can help elucidate the dynamics of biological invasions, which are fueled by the constant expansion of international trade. The introduction of European gypsy moth (Lymantria dispar dispar) into North America is a classic example of human‐aided invasion that has caused tremendous damage to North American temperate forests. Recently, the even more destructive Asian gypsy moth (mainly L. d. asiatica and L. d. japonica) has been intercepted in North America, mostly transported by cargo ships. To track invasion pathways, we developed a diagnostic panel of 60 DNA loci (55 nuclear and 5 mitochondrial) to characterize worldwide genetic differentiation within L. dispar and its sister species L. umbrosa. Hierarchical analyses supported strong differentiation and recovered five geographic groups that correspond to (1) North America, (2) Europe plus North Africa and Middle East, (3) the Urals, Central Asia, and Russian Siberia, (4) continental East Asia, and (5) the Japanese islands. Interestingly, L. umbrosa was grouped with L. d. japonica, and the introduced North American population exhibits remarkable distinctiveness from contemporary European counterparts. Each geographic group, except for North America, shows additional lower‐level structures when analyzed individually, which provided the basis for inference of the origin of invasive specimens. Two assignment approaches consistently identified a coastal area of continental East Asia as the major source for Asian invasion during 2014–2015, with Japan being another source. By analyzing simulation and laboratory crosses, we further provided evidence for the occurrence of natural Asian–North American hybrids in the Pacific Northwest, raising concerns for introgression of Asian alleles that may accelerate range expansion of gypsy moth in North America. Our study demonstrates how genetic data contribute to bio‐surveillance of invasive species with results that can inform regulatory management and reduce the frequency of trade‐associated invasions.

Mitochondrial Genomes, Phylogenetic Associations, and SNP Recovery for the Key Invasive Ponto-Caspian Amphipods in Europe

“…In our study, we detected multiple SNPs across most of the mitochondrial genes for different populations, both for D. villosus and D. haemobaphes . Detection of SNPs at the species level can be valuable to the study of invasive organisms, helping one to identify their source population(s) and determine their invasion corridor(s) [ 71 , 72 , 73 ]. Growing accessibility, together with falling prices of high-throughput sequencing, will undoubtedly make multigene SNP data a primary resource to study biological invasions [ 74 ].…”

Identification of Core Genes of Toll-like Receptor Pathway from Lymantria dispar and Induced Expression upon Immune Stimulant

“…However, there are few studies to investigate the role of the TLR pathway in mediating resistance to baculovirus, which is a large DNA virus and an important biology factor of naturally controlling insect populations. The gypsy moth, Lymantria dispar (Lepidoptera: Lymantriidae), is a polyphagous insect pest of forests worldwide, whose larvae have been reported to exploit a wide variety of host plants belonging to 400–600 species [ 14 ]. The TLR pathway and its underlying immune mechanism against baculovirus in L. dispar have not been comprehensively addressed to date.…”

Climate Warming Since the Holocene Accelerates West–East Communication for the Eurasian Temperate Water Strider SpeciesAquarius paludum

“…For the ecological niche analyses, a total of 1,645 occurrence localities of A. paludum based on our collection, literature records, and online database from the Global Biodiversity Information Facility online database (GBIF, http://www.gbif.org/ ) were used for niche modeling. The coordinates of the other five Eurasian temperate species for niche model building were directly downloaded from the GBIF database and incorporated with sites from published studies ( Wu et al 2015 , 2020 ; Krehenwinkel et al 2016 ), which determined 390 localities for A . bruennichi , 511 for D .…”