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Outbreak of the stick insect, Ramulus mikado (Phasmatodea, Phasmatidae), in the Akashina area of Japan (Azumino City, Nagano Prefecture)
Author(s) -
Yano Koki,
Ozaki Takahisa,
Suzuki Tomoya,
Yamazaki Haruka,
Nasuno Masayoshi,
Degawa Yosuke,
Tojo Koji
Publication year - 2021
Publication title -
entomological science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 28
eISSN - 1479-8298
pISSN - 1343-8786
DOI - 10.1111/ens.12467
Subject(s) - outbreak , biology , zoology , insect , population , ecology , demography , virology , sociology
In August 2017, an outbreak of the stick insect, Ramulus mikado (Rehn, 1904), was observed in the Akashina area in Central Japan. This stick insect is a wingless, non‐flying species that inhabits East Asia. Although it seems that the occurrence of many individuals emerging together had been observed in the 2 or 3 years prior, the outbreak in 2017 was on a far larger scale, and was therefore not comparable to anything observed previously. Indeed, it was also observed that the stick insects fed on almost all leaves of the large Japanese zelkova trees until the trees were bare. Additionally, mass gatherings of the stick insects on the walls of houses in the area were observed. In Japan, there have been no other reports of outbreaks of R. mikado , thus this represents a unique case. In the Akashina area, the population's sex ratio is heavily biased towards females, as is the case with other populations, indicating that they reproduce parthenogenetically. However, among our observations, one individual of the 724 specimens collected in the present study was in fact a male. As there have only ever been about 10 observed cases of R. mikado males, the male individual collected in our field research constitutes a valuable record.