Assessing the Population Structure and Invasion Risk in Suitable Areas of the Rice Pest Leptocorisa acuta (Hemiptera: Alydidae).

Rice (Oryza sativa) provides a major food resource worldwide, playing an important role in the global economy. Leptocorisa acuta (Hemiptera: Alydidae), commonly known as the rice seed bug, is a major pest of paddy crops in many rice-growing regions and it is considered a potential invasive pest in the United States. Here, we investigated the genetic structure and demographic history of 18 populations sampled from China and southeast Asia using double-digest restriction site-associated DNA sequencing (ddRAD-seq). Then, we performed niche modeling based on occurrence records under current and future climate scenarios. Our analyses suggested that the lack of genetic structure among populations of L. acuta is related to recent diversification, strong flight, and dispersal capability, leading to a high level of gene flow. The demographic history was not strongly affected by the last glacial maximum. Ecological niche modeling predicts that future suitable areas will expand in Asia and America, relative to the current conditions. The ecological niche results demonstrated that L. acuta is a potentially invasive pest to the United States (mainly Florida and nearby areas) under current and future scenarios. Moreover, the moderately and highly suitable areas will increase in America (primarily located in North America, namely Florida and nearby areas, and Mexico), Central American and Caribbean countries, and some regions of South America. Some South American countries have extensive rice crops and broadly suitable habitats that may indicate a higher invasion risk. Through population genetics, our study supports the strong dispersal capacity of this insect pest and calls for vigilance against its invasion in some countries in the Americas.