Shift of Host Range for the Immature Stages of the Lanternfly, Pyrops watanabei (Matsumura) (Hemiptera, Fulgoridae) Native to Taiwan

SIMPLE SUMMARY: Pyrops watanabei is a lanternfly species native to Taiwan, and the adults are frequently on Triadica sebifera in summer. Compared to adult longevity, the developmental duration of immature stages from eggs to adult emergence is much longer. Although few records exist, the plants preferred by the immature stages had not been determined prior to this study. Thus, a one-year investigation was conducted to verify the oviposition site preference, determine the plants preferred by nymphs, and examine the change of host ranges with time and development. We establish that Heptapleurum heptaphyllum is not only the preferred egg-laying site, but the main host plant for nymphs from September to the next April, according to our investigations in northern Taiwan. Moreover, the preferred host plant for the nymphs shifts to Triadica sebifera from May onwards to adult emergence. ABSTRACT: Although Pyrops watanabei is a species native to Taiwan, many fundamental aspects of the species are still poorly documented. Populations of the lanternfly in locations of northern Taiwan were found in abundance and were suitable for the conduction of an investigation from 1 July 2021 to 30 June 2022. We established the shift in the main host plants with different developmental stages. The occurrence of immature individuals on Heptapleurum heptaphyllum increased with age from eggs to nymphs in the third instar; however, it declined from the fourth instar onwards due to a shift in preference to Triadica sebifera. In 2021, the earliest detection of an egg mass was on 1 July. More eggs were recorded in August, and some could be found in September and October of the same year. In 2022, we found an egg mass on 28 June. In August 2021, nymphs in the first and second instars were detected. Then, nymphs in the third and fourth instars appeared after September and October 2021, respectively. Furthermore, nymphs in the fifth instar were sighted as late as March 2022. Finally, this study will provide a basis for further evaluation of the impact of invasion of Pyrops candelaria on the ecology of Pyrops watanabei.