Journal of Threatened Taxa | www.threatenedtaxa.org | 26 July 2021 | 13(8): 19168–19170
ISSN 0974-7907 (Online) | ISSN 0974-7893 (Print)
#6425 | Received 17 July 2020 | Final received 12 May 2021 | Finally accepted 27 June 2021
Rediscovery of Watson’s Demon Stimula swinhoei swinhoei (Elwes & Edwards, 1897) (Lepidoptera: Hesperiidae: Hesperiinae) in Meghalaya, India after 60 years
Suman Bhowmik 1 & Atanu Bora 2
1 Lepidoptera Conservation and Research Division, Wild Tripura Foundation, Agartala, Tripura, 799007, India.
2 Department of Zoology, Moran College, Moranhat, Assam, 785670, India.
firstname.lastname@example.org, email@example.com (corresponding author)
The monotypic genus Stimula is represented by a single species Watson’s Demon Stimula swinhoei (Varshney & Smetacek 2015). Stimula swinhoei was first introduced as Watsonia swinhoei by Elwes & Edwards in 1897 through the type specimens of Col. Swinhoei. Later, this species was treated as Stimula swinhoei (Evans 1932, 1949). Altogether two subspecies occur: Stimula swinhoei swinhoei – Khasi Hills, Sikkim, Assam, Sadon, northern Myanmar, and North Shan State and Stimula swinhoei disca – Myanmar, northern Thailand, Laos, and Yunnan. The Indian subspecies was last recorded by Cantlie from Khasi Hills, Meghalaya in 1956 (Cantlie 1956). Since then, there is no record of the species in Meghalaya (Radhakrishnan et al. 1989; Alfred 1999; Hatter et al. 2004; Kunte et al. 2012; Sondhi et al. 2013). The subspecies swinhoei is, however, recently recorded from Panbari Reserve Forest, Assam (Gogoi 2013). This observation discusses the rediscovery of the Indian subspecies after a gap of 60 years for Meghalaya along with small note on its identification and current habitat of the butterfly in the state (Image 1).
The present rediscovery is based on an opportunistic survey in Khasi hills as a part of the butterfly inventory and monitoring programme of northeastern India. On 20 February 2016 at about 1245 h, one of the authors, Atanu Bora photographed a skipper butterfly feeding on bird droppings adjacent to a hill stream in Riwai village (25.196N & 91.900E; at approximately 430m), Meghalaya. The butterfly exactly matched the original description of the underside of Stimula swinhoei in the published literature (Elwes & Edwards 1897; Evans 1949).
Stimula swinhoei is identical to Ancistroides nigrita but differs in the following characters (Elwes & Edwards 1897; Evans 1932, 1949):
1. Stimula swinhoei: The marginal third of only forewing paler. Additionally, large pale area on the dorsum of upperside forewing (hidden in the documented photographs). Underside hindwing uniformly dark brown (Image 3).
2. Ancistroides nigrita: The marginal third of both wings paler. Underside forewing dorsum not pale brown unlike Stimula swinhoei (Image 3).
Stimula swinhoei was last recorded by Cantlie from Khasi Hills of Meghalaya in 1956. However, none of the authors has recorded this species in Meghalaya afterwards. This rediscovery indicates that a population of the butterfly still exists in some restrictive habitats of Khasi hills. Currently, no information is available on ecology of the species in India. Our observation suggests that Stimula swinhoei can be found perching on the hill streams inside forest (Image 4). During daytime, the species can be found puddling on rocks, wet patches and bird droppings nearby hill streams or waterfalls. Additional records in future surveys will help to map the distribution of this species in the Indian subcontinent. The species might have been overlooked in the past historic works because of its close similarity with Ancistroides nigrita. We strongly hope that our observation will help Lepidopterists and butterfly enthusiast across the country in identification of the species and the habitat information can be used for proper monitoring of this butterfly in future.
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