Probing the sequestration of quassinoids by the spotted lanternfly, Lycorma delicatula White

Spotted lanternfly (SLF) (Lycorma delicatula White [Hemiptera: Fulgoridae]) is a large phloem-feeding planthopper, native to Asia and invasive to the United States as of 2014. Since the arrival of SLF in Pennsylvania, it has spread to 15 additional states and is considered a highly polyphagous pest, causing damage to over 100 species of forest, agricultural, and ornamental plants. Despite its polyphagous nature, SLF strongly prefers the tree-of-heaven (ToH) (Ailanthus altissima (Mill.) Swingle [Sapindales: Simaroubaceae]) as a host plant, likely having coevolved with this plant species in its shared native range. Several sources of evidence suggest that SLF sequesters a group of phytotoxin decanortriterpenoids called quassinoids, from the ToH, for use as antipredator defense. However, still little is known about the quantitative uptake of quassinoids by the different developmental stages of SLF and the tissue-specific storage of these compounds in the insect body. Here we present the development of novel feeding assays based on a liquid diet to probe the sequestration of quassinoids in SLF nymphal and adult life stages. Our findings set the stage for future studies to determine molecular mechanisms of quassinoid transport and storage. Moreover, our assays will be useful to assess SLF feeding behavior and rearing potential and develop insecticide- and RNAi-based control strategies.