Samia cynthia (Drury, 1773)

Wu, Yujie, Peigler, Richard S. & Liu, Zhengyang, 2025, Ecological observations on the genus Samia Hübner, 1819 (Lepidoptera, Saturniidae) of China, especially the natural hostplants, Nota Lepidopterologica 48, pp. 251-268 : 251-268

1. Samia cynthia (Drury, 1773)

Fig. 1 A, B

Material examined.

LIAONING: ( AD): Seven empty cocoons; Zanthoxylum bungeanum ( Rutaceae ); the coast of Ganjingzi District, Dalian, ca. 23 m; 03 June 2017. ( AD): A mature larva; Zanthoxylum sp. ; Fenghuangshan, Fengcheng, Dandong, 200 m; 14 September 2019. ( OD): About thirty mature larvae; mostly feeding on Ailanthus altissima ( Simaroubaceae ) and some on Z. bungeanum ; urban area of Lianshan District, Huludao, Liaoning, 29 m; 22 August 2020. BEIJING: ( OD): Mature larvae and cocoons, unknown number; A. altissima , Z. bungeanum and Phellodendron amurense ( Rutaceae ); suburban Haidian and Changping Districts; August 2019 –2023. ( AD): A cluster of L 2 larvae; A. altissima , ca. 3 m tall; Badaling National Forest Park, Yanqing District, 577 m; 23 June 2019. SHANDONG: ( AD): A total of thirty mature larvae, about 1–12 individuals on each plant; cultivated Z. bungeanum in plantations, 3 - meter-tall trees; Sibaoshan of Zichuan District and Hudieyu of Boshan District, Zibo, ca. 30–130 m; late August to early September, 2006 and 2009. ( OD): A mature larva; Tetradium daniellii ( Rutaceae ); Fohuishan, Jinan, 290 m; 23 August 2010. ( AI): About 500 g of empty cocoons; Z. bungeanum and A. altissima ; the coast of Longkou, Penglai of Yantai, ca. 49 m; March 2024. JIANGSU: ( AI): Twenty wild cocoons; Camphora officinarum ( Lauraceae ); Guanyun County of Lianyungang, Jiangsu, ca. 4 m; 19 December 2021.

Notes.

As the type-species of the genus, polyphagous S. cynthia has long been known as the ailanthus silkworm / silkmoth due to one of its main hostplants in nature. Besides being another main feeder on Z. bungeanum , this species has also been recorded as a significant pest of Ziziphus jujuba ( Rhamnaceae ), Paulownia elongata ( Paulowniaceae ), Punica granatum ( Lythraceae ) and Lagerstroemia indica ( Lythraceae ) in the wild in Hebei (e. g., Zhang et al. 1994; Li et al. 2001; Dai 2005). S. cynthia is commonly reported from most provinces in northern China but remains unknown in the semiarid regions of the Loess Plateau and the Mongolian Plateau. Furthermore, although specimens have been recorded from Shanghai, Jiangxi, and Zhejiang ( Peigler and Naumann 2003: 98–99), another species is more common in these southern areas (see section 2). The habitat of S. cynthia ranges from plains to hills, including near the coasts, and it flies both in cities and forests. The species is probably univoltine or bivoltine in most northern Chinese habitats. Adults emerge from May to September, according to field observations by Du et al. (2010) in Liaoning and Zhengyang Liu in Beijing. In Tianjin, Wen et al. (2001) reported that it is bivoltine, and many studies note that there are 2–3 generations naturally in Hebei (e. g., Luan 1994; Zhang et al. 1994; Zhang 1995; Zhang et al. 1996; Sun 1998; Li et al. 2001), as well as in the wild in Shandong (e. g., Nie et al. 2025). The wings usually have a dark olive-green tinge, and there are five larval instars. During L 1–4 the individuals are sometimes clustered, and the mature larvae are solitary (Fig. 3 J ). S. cynthia overwinters as pupa, with the grayish or brownish cocoons which usually have peduncles and usually hang on the hostplants, but in captivity it can occasionally be seen spun away from the hostplant. This moth was once one of the main sericulture species in ancient China (e. g., Jiang et al. 1996; Peigler 2020), and the cocoons were collected and used to make hand-spun yarns, mainly in rural Shandong (e. g., Wallace 1866; Rondot 1887: 78; Fauvel 1895: 76). However, this industry almost disappeared after Chinese Economic Reform (ca. 1978) and commercial silk is no longer found on the market.

Figures

Figure 1. Adults of Samia spp. from China, dorsal views. A. S. cynthia ♂, Heshan, Donggang District, Rizhao, Shandong, ca. 334 m, 24 March 2024; B. S. cynthia ♀, Beijing Botanical Garden, Haidian District, Beijing, ca. 316 m, March 2024; C. S. wangi ♂, Longjiang Township, Yongfu County, Guilin, Guangxi, ca. 214 m, 20 March 2024; D. S. wangi ♀, Linfengshan, Fuyang District, Hangzhou, Zhejiang, ca. 370 m, 22 April 2024; E. S. kohlli ♂, Tuanjie Township, Xishan District, Kunming, Yunnan, ca. 2200 m, September 2023; F. S. kohlli ♀, Gejiu, Honghe Hani Yi Autonomous Prefecture, Yunnan, ca. 1780 m, 26 July 2023. Scale bar: 3 cm.

Figure 3. Preimaginal materials of Samia spp. of China. A – I, K – M, P. Individuals photographed in the wild. N, O, Q. Captive individuals. A. Ova of S. wangi on leaf underside of Styrax sp., Hangzhou; B. Ovum shells of S. kohlli on leaf underside of Z. armatum, Kunming; C. Ovum shells of S. watsoni on leaf upperside of P. corymbosus, Hangzhou; D. Ovum shells of S. watsoni on leaf upperside of S. gemmata, Hangzhou; E. Larval cluster of S. wangi L 3, dorsal view, on leaf underside of H. acerba, Hangzhou; F. Larval cluster of S. kohlli L 2 (pre-ecdysis), dorsal view, on leaf underside of Z. armatum, Kunming; G. S. watsoni L 2, dorsal view, on leaf underside of P. corymbosus, Hangzhou; H. S. kohlli L 3, dorsal view, on the leaf underside of C. nepalensis, Kunming; I. S. watsoni L 4, dorsolateral view, on leaf underside of P. corymbosus, Hangzhou; J. S. cynthia L 5 (mature), dorsolateral view, on C. officinarum; K. S. wangi L 5 (mature), lateral view, on S. japonica, Hangzhou; L. S. kohlli L 5 (mature), lateral view, on C. nepalensis, Kunming; M. S. canningi L 5 (mature), lateral view, on Zanthoxylum sp., Xishuangbanna; N. S. ricini L 5 (mature), lateral view, on C. nepalensis; O. S. watsoni L 5 (mature), lateral view, on P. corymbosus; P. Cocoon of S. wangi, on C. officinarum, Shanghai; Q. Cocoon of S. watsoni, on P. corymbosus.