Host Plants for the Lanternfly Saiva formosana Kato, 1929 (Hemiptera, Fulgoridae) Endemic to Taiwan, and Parasitism of Its Eggs by Wasps.

Since Saiva formosana Kato, 1929 was first reported as a new species in Taiwan; there have been few published reports on its ecology, and fundamental knowledge of this species is still lacking. The objectives of this study are to (1) determine the preferred plants of adults, egg-laying, and nymphs, (2) analyze the change in host plants with time and development, and (3) explore the relationship between the survival of eggs and parasitism by their wasps. We detected the adults of this species between May and September 2023, and again in April 2024, mainly on Elaeocarpus decipiens F. B. Forbes & Hemsl. During our investigation, we frequently observed parasitic wasps ovipositing on the egg masses. We established that most egg masses produced only Saiva nymphs or Anastatus adults. This lanternfly might better survive parasitic pressure by laying lower numbers of eggs per mass across a broader range of plant species. The first batch of hatching nymphs was found on Magnolia compresssa Maxim. on 20 June 2023; however, most nymphs in the second and third instars were detected on Ficus fistulosa Reinw. ex Blume, between August and October 2023. After the autumn, the occurrences of nymphs increased on Heptapleurum heptaphyllum (L.) Y. F. Deng which probably served as a shelter for overwintering.