Analyses of adult transcriptomes from four different populations of the spongy moth, Lymantria dispar L., from China and the USA

Authors: WANG, YIMING - Beijing Forestry University; Sparks, Michael; Harrison, Robert - Bob; SHI, JUAN - Beijing Forestry University

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/10/2022
Publication Date: 10/29/2022
Citation: Wang, Y., Sparks, M., Harrison, R.L., Shi, J. 2022. Analyses of adult transcriptomes from four different populations of the spongy moth, Lymantria dispar L., from China and the USA. Scientific Reports. https://doi.org/10.1038/s41598-022-18377-4.
DOI: https://doi.org/10.1038/s41598-022-18377-4

Interpretive Summary: The spongy moth, Lymantria dispar, is a forest pest that is grouped into two biotypes: the European spongy moth, found in Europe and North America; and the Asian spongy moth, found in China, Russia, Korea, and Japan. Outbreaks of this pest can result in tremendous damage to trees and forests. While European spongy moth females are flightless, Asian spongy moth females are very flightworthy. As a consequence, it is expected that the invasion of North America by Asian spongy moth would result in damage to forests over a wider geographic area. To figure out why Asian spongy moth females can fly well while European spongy moth females have an impaired flight capability, we examined the expression of genes in female adults of two different Chinese populations of Asian spongy moth and two different USA populations of European spongy moth. We also examined the expression of genes in virgin moths and compared them to gene expression in moths after mating and egg-laying, because flight capability also decreases after egg-laying. While many differences in the levels of expression of individual genes between the Chinese and USA populations were identified and documented, far fewer differences in gene expression were observed between virgin moths and moths after mating and oviposition. The information in this study contributes to progress towards understanding the genetic factors controlling the flight ability of spongy moth, and will be of interest to those in academia, government, and industry who work with spongy moths and other invasive forest pests.

Technical Abstract: The spongy moth Lymantria dispar, formerly known as the gypsy moth, is a forest pest that occurs as two different biotypes: the European spongy moth (ESM), Lymantria dispar dispar, which is distributed in Europe and North America; and the Asian spongy moth (ASM), which consists of subspecies Lymantria dispar asiatica and Lymantria dispar japonica and is distributed in China, Russia, Korea, and Japan. The Asian biotype is classified as a quarantine pest by the U.S. Department of Agriculture because of the superior flight ability of adult females compared to females of the European biotype. To identify genes that potentially account for differences in female flight capability between the two biotypes, we assembled and compared whole-genome transcription profiles of two North American populations of ESM and two Chinese populations of ASM, including samples of unmated female adults and females after mating and oviposition. Of 129,286 unigenes identified, 306 were up-regulated in ASM samples relative to ESM, including genes involved in egg production. In contrast, 2,309 unigenes were down-regulated in ASM samples, including genes involved in energy production. Although a previous study found that ASM female flight was reduced after oviposition, a comparison of gene expression before and after mating and oviposition did not reveal any genes which were consistently up- or down-regulated in the two ASM populations.