Diverse Host Plants of the First Instars of the Invasive Lycorma delicatula: Insights from eDNA Metabarcoding

SIMPLE SUMMARY: The globalization of human activities, especially in agriculture, has facilitated the range expansion of insect pests, promoting species invasions in new territories. Here, we focused on the invasive spotted lanternfly, Lycorma delicatula, an important economic pest, accidentally introduced in the United States and first detected in 2014. Our study investigated host-plant usage by the first nymphal instars, which are more challenging to find and monitor than other stages. Using DNA metabarcoding of nymphal gut contents (i.e., detection of DNA from multiple ingested plants) in this study we determined and characterized the ingested plants that could be included in a broad host-plant range of early nymphal stages of L. delicatula. This, in turn, will have important applications for developing effective management programs to control the invasive spotted lanternfly. The results from our study will be of great interest for all the forest managers and growers in the potential (national) range of the spotted lanternfly, and will help them ultimately minimize their efforts and expenses needed for managing this important pest. ABSTRACT: Identification of host plants of the invasive spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), has been the focus of many studies. While the adults and late nymphs are relatively easy to observe on plants and to use for molecular gut-content analysis, studying the early instars is more challenging. This study is the continuation of our ongoing efforts to determine the host range for each developmental stage of L. delicatula. In the present study, we focused exclusively on the first nymphal instars, and we used a novel approach, utilizing “bulk” DNA extracts for DNA metabarcoding of nymphal gut contents, to identify all the detectable plants that the nymphs had ingested prior to being collected. We were able to obtain high-quality amplicons (up to 406 bp) of a portion of the rbcL gene and detect 27 unique ingested plant species belonging to 17 families. Both native and introduced plants with the prevalence of trees and grasses were present among the ingested plants. We also identified 13 novel host plants that have not been previously reported for L. delicatula on the U.S. territory. The results from our study have important applications for developing effective programs on early monitoring of invasive L. delicatula.