Host Plants of the Immature Stages of the Invasive Longan Lanternfly, Pyrops candelaria (L.) (Hemiptera, Fulgoridae) in Taiwan

SIMPLE SUMMARY: The longan lanternfly, Pyrops candelaria (L.), was recently introduced to Taiwan, and the ongoing spreading of the species may have an impact on native fauna, flora, and environment. The adult of this species is known to prefer the longan tree as a host; however, the preferred host plants for the immature stages have not yet been determined until this study. Thus, we aimed to (1) determine the host range for egg-laying, (2) verify the host plants preferred by nymphs, and (3) analyze the shift of host ranges with different developmental stages. Triadica sebifera (L.) Small is the main host plant for nymphs according to our investigations in different locations around northern Taiwan. The results of this study provide great strategic value for decision-makers to allow for effective control of the target tree species. ABSTRACT: The longan lanternfly, Pyrops candelaria (L.), has been invading mainland Taiwan since 2018, but the distribution of the species has been confined to northern Taiwan until now. The manual removal of the adult insects from the longan is still the main control strategy because of the uncertainty around other key host plants, especially for eggs and nymphs. In this study, large numbers of eggs and nymphs were found on Triadica sebifera (L.) Small and Acacia confusa Merr. The occurrence of immature individuals on Triadica sebifera increased with developmental stage from eggs to the last instar from May to July 2021. On 30 April, the first egg mass was recorded. More egg masses were recorded in May, and some could be found in July. In May, only two younger instars were detected. Third and fourth instars began to appear from June, while the fifth instar was mainly recorded from July onwards. The results of this study provide great strategic value for decision-makers to allow for effective control of the target tree species. For now, we proved that longan and pomelo trees, preferred by adults, are not the key hosts for the immature stages of this insect, because few immature individuals were found on them. Therefore, we suggest that the existence of Triadica sebifera should be considered when analyzing possible spreading areas of this invasive lanternfly in Taiwan.