Planthopper diversity on palms in Madagascar and the identification of putative phytoplasma vectors

Recent surveys in the Neotropics focusing on planthoppers associated with palms have uncovered a high diversity of undiscovered taxa. These surveys were a result of a renewed interest in vector identification of palm lethal decline phytoplasmas due to the introduction of lethal bronzing (LB) in Florida, U.S.A. The high diversity and specialization of planthoppers on palms in the Neotropics raised the question of whether this relationship existed in other tropical, biodiversity hotspots. Initially, Madagascar was selected due to high levels of endemism and diversity, especially in palms, in addition to a surprising lack of diversity documented in planthoppers. However, in 2021, a new strain of palm lethal decline phytoplasma was documented in Madagascar. With a poor record of platnhoppers in Madagascar and the occurrence of a novel strain of phytoplasma, an expedition was launched in early 2023 and again in early 2024 to survey planthoppers associated palms with the goal of discovering novel taxa and identifying a putative vector of the phytoplasma in palms. Between both expeditions, thus far 71 species of derbid have been collected. All of them have been confirmed to represent new species, many representing novel genera. For the Cixiidae, 60 species were collected with some representing previously discovered taxa. In addition, a species complex of cixiids was discovered on phytoplasma infected palms and have tested positive with preliminary assays. These findings shed light on an enormous, undiscovered diversity of planthoppers as well as support a putative vector of palm phytoplasmas in Madagascar.