Hestina assimilis

Basic information
Scientific name	Hestina assimilis	Click to magnify
Common names	Red ring skirt; Nymphalid butterfly
Higher taxon	Nymphalidae, Papilionoidea, Lepidoptera
Natural range	Northern Vietnam, southern to eastern continental China, Korean Peninsula, and peripheral islands (e.g., Cheju Is.). Two other subspecies are distributed in Amami Islands of southern Japan (H. s. shirakii) and Taiwan (H. s. formosana).
Habitat	Around human habitat.

Invasion information
Range in Japan	There have been recorded in wide area of Kanto Plain. Kanagawa, Tokyo, Saitama, Chiba, Ibaraki, Tochigi and Gunnma Pref. and Izu-Oshima Is. Recently, there have been several observation records in Shizuoka, Ishikawa and Yamanashi Pref.
Origin	Possibly continental China.
Date	The first record in Japan was in 1995 at Saitama Pref. (not established), and the first record of reproduction in Japan was in 1998 at Kanagawa Pref. They also observed at Izu-Oshima Is. in 2009, and at Ibaraki Pref. in 2011.
Route	Deliberate: Possibly release by some people (“butterfly release guerrilla”).
Impact	Potentially: Competition with native butterflies. Native organism(s) affected: Several butterflies using Celtis sinensis (e.g., Hestina japonica, Sasakia charonda charonda, Libythea celtis celtoides)
Regulation in Japan	Release of this species is prohibited in Aichi Pref. by a prefectural code. Nymphalidae is designated as a Quarantine Pest (the Plant Protection Law).
Introduced range in other countries	None.

Reference

Notes

JWRC (ed) (2008) A Photographic Guide to the Invasive Alien Species in Japan. Heibonsha, Tokyo (in Jpn)
Kato (2007) An attempto to clarify environmental stimuli responsible for the production of white morphs in a nymphalid butterfly Hestina assimilis. Butterflies. 45, 12-19 (in Jpn)
Shirzu (1960) Butterflies of Formosa in Color. Hoikusha, Osaka (in Jpn)
Plant Protection Station (2011) The Plant Protection Act. Quarantine Pest List. (Accessed on 2012-4-26) http://www.pps.go.jp/law_active/Notification/basis/5/245/html/245.html (in Jpn)
Karasawa et al. (2012) Records of Hestina assimilis (Lepidoptera: Nymphalidae) Collected or Observed in Ibaraki Prefecture, Central Japan. Bulletin of Ibaraki Nature Museum. 15, 3-5 (in Jpn)
etc.

Hestina assimillis (without Hestina assimillis shirakii) is listed as invasive alien species. Some hybrids were emerged in a cross experiment between this subspecies and a native congener H. japonica. However, the low rate of successful adult eclosion implied the small risk of introgression.