Objective 1: Selection of morphological characteristics for the determination of life stages of the cicada H. maculaticollis.
Objective 2: Implementation of molecular analysis on COI gene for the identification of the cicada H. maculaticollis (Hemiptera: Cicadidae).

Theoretical results:
- Overall, 14 first-stage nymphs were collected and determined as H. maculaticollis by comparing COI sequences with GenBank. In those samples, only nine samples obtained four morphological characteristics for subsequent analysis: head width 0.310 ± 0.029 mm, thorax width 0.408 ± 0.045 mm, abdomen width 0.256 ± 0.051 mm, and body length 1.109 ± 0.181 mm. In addition, 12 other nymphs were provided by the research group from Ewha Womans University, making the total number of first nymphs to 21 individuals.
- Another 326 nymphs of other stages were also collected and determined as H. maculaticollis by comparing COI sequences with GenBank. From charts of morphological characteristics, remarkable discriminant between the last two stages was clearly observed. Moreover, one or two additional stages may exist between the first stage and the last two stages. The size of head width was relatively stable with smaller variance compared to other morphologicla characteristics. Thorax width of first stages was also more stable than other stages.
- The log-transformed scenarios displayed clustering results of group 1 in line with first-stage instars (21 individuals). Specifically, five- and six-stage scenarios for log-transformed data displayed group 2 of 1 individual which was consistent with the single collected individual.
- Specifically, the five nymphal stage grouping for log-transformed data was the model with highest pseudo-F value (5785.68), thus being chosen as the best fit model. Additionally, this five-stage scenario generated clustering results comparable to the number of first instars employed in this study. Therefore, we concluded that five stages were the most relevant nymphal development for H. maculaticollis nymphs.
Applied results: A statistical method has been successfully developed for the fast and efficient delimitation of nymphal life stages of H. maculaticollis which could be widely applied for nymphs of other cicada species as well as other insects.

- A dataset of morphometrics of H. maculaticollis nymphs.
- A proposed statistical method for efficient nymphal life stages of H. maculaticollis.
- An ISI article published on Journal of Asia-Pacific Entomology (Impact factor 1.3).

- Scientific papers in referred journals (list): 01 paper published on Journal of Asia-Pacific Entomology.
Nguyen, Hoa Quynh, Erick Kim, Yoonhyuk Bae, Soyeon Chae, Seongmin Ji, Jiman Heo, Sungsik Kong, Thoa Kim Nguyen, Thai Hong Pham, and Yikweon Jang. "An effective method for accurate nymphal-stage delimitation of the cicada Hyalessa fuscata." Journal of Asia-Pacific Entomology (2022): 101952.

The proposed research should be maintained and facilitated towards the establishment of a national dataset of insects’ nymphal development in Vietnam.