Lepidoptera Linnaeus, 1758 which includes butterflies and moths, is one of the largest insect orders consisting of 45 super families and having 157,424 species described (Van Nieukerken et al. 2011). It constitutes 10% of the total described species of living organisms (Mallet 2007). Of these, moths form roughly 85% of all known Lepidoptera, with over 12000 known species of moths from the Indian subcontinent (Chandra 2007). Moths are ecologically and economically significant as a primary food source for vertebrate insectivores, as pests of crop plants (Common 1990), pollinators (MacGregor et al. 2015), food for humans (Zagrobelny et al. 2009) and model organisms in scientific research (Roe and Just 2009). Nevertheless, the recent reports on insect decline are alarming and it is also evident in decline in moth diversity and abundance around the world (Hallmann et al. 2020). Numerous factors contribute to the decline of moths, such as rapid urbanisation, habitat loss, artificial light, intensive agriculture, pesticide pollution and lack of conservation policies (Dennis et al. 2019). These reports on global insect declines highlight the need for better conservation and management; however, they need to occur in tandem with ongoing monitoring and cataloguing of insects. Much of the work on Indian moth fauna was done pre-independence, including Hampson (1891), Hampson (1892), Hampson (1894), Hampson (1895), Hampson (1896), Fletcher (1920), Fletcher (1932), Fletcher (1933), Moore (1880), Moore (1882), Moore (1884), Bell and Scott (1937) and while they are extensive contributions to Indian moth fauna, these works are in need of a systematic update with additional modern surveys and current taxonomy. The more recent studies on moth fauna by Indian authors have been growing in number and include surveys, based checklists on the moth fauna of specific regions, viz. Mathew and Rahmathulla (1995) (Silent Valley National Park, Kerala, 318 species), Rose (2002) (Jatinga, Assam, 81 species), Shubhalaxmi et al. (2011) (northern Western Ghats, 418 species), Gurule and Nikam (2013) (northern Maharashtra, 245 species), Sondhi and Sondhi (2016) (Garhwal, Uttarakhand, 248 species), Singh et al. (2017) (North East Jharkhand, 81 species), Dey et al. (2018) (Wildlife Institute of India, Dehradun, 291 species), Sondhi et al. (2018) (Agastyamalai Biosphere Reserve, Kerala, 282 species), Dar et al. (2020) (Jammu and Kashimir, 461 species) and Bhagat (2020) (Jammu and Kashmir, and Ladakh, 55 species). There has been a tendencey to focus on studying regions of higher biodiversity, including the Western and Eastern Himalayas and the Western Ghats; however, there has been much less work done from regions with higher levels of human disturbance or metropolitian cities in India.

In this study, we focus on the moth fauna of Delhi, the National capital territory of India, one of the largest growing metropolitan centres in the world with an estimated population of 23 million (MPD 2021). Delhi, with a geographical coverage of 783 km² , extends on the western bank of River Yamuna between 28º12' and 28º53' N latitude and 76º50' and 77º23' E longitude and is bound on the northeast by the Indo-Gangetic plain and on the southeast by the Thar Desert (Dakshini 1968). The prominent component of the natural vegetation is the Delhi Ridge forest which is an outcrop of the Aravali Hills, one of the oldest chains of hills in the world. Open scrub forest, classified under the Tropical Dry Thorn Forest type (Champion and Seth 1968), covers a large extent of the ridge. Such vegetation type is widely distributed in the arid and semi-arid zones of the Earth where the total annual rainfall ranges from 50-100 mm. Tree species commonly found in Delhi, in such vegetation include, Acacia leucoplachia, Prosopis cineraria, Ziziphus nummularia, Anogeissus pendula etc. (Maheshwari 1953, Maheshwari 1963). Additionally, Prosopis juliflora, an exotic species introduced, as part of the afforestation drive, also dominates this thorny vegetation (Sinha 2014). Another prominent feature of the natural vegetation in Delhi is the Dichanthium-Cenchrus-Lasiurus grasslands (Dabadghao et al. 1973). The fertile alluvial plains of the State support agricultural crops which also influence the moth diversity of the region by favouring many heteroceran agricultural pests. Donahue (1966), in his study of Butterflies of Delhi, identified two distinct habitats in Delhi: the arid xerophytic Aravalli Ridge (Delhi Ridge) and mesophytic urban nursery area. Though the city is a highly urbanised landscape with a human population of about 16.75 million (as per 2011 census), it holds a forest cover of about 13.18% (Forest Survey of India 2019), one of the largest percentages of forest cover when compared to other Indian cities. This, along with factors like the presence of the Yamuna River and its nearness to the Himalayas, adds to factors that augment biodiversity of the area. Much of the rainfall in Delhi is received during the months of July to August during which the otherwise dry vegetation shows luxuriant growth and supports the insect diversity.

In general, the insect fauna of Delhi has received less attention with only very few groups like butterflies (Lepidoptera) (Biswas et al. 2017) and Odonata (Nazneen 2019) being well documented. The studies on moth fauna of Delhi were always insufficient, the State fauna series of Delhi, published by the Zoological Survey of India in the year 1997, included only 11 species of moths (Ghosh and Varshney 1997). Later, after two decades, Paul et al. (2016) added 36 species of moths to the biodiversity of Delhi which included mostly agricultural pests. The recent checklist of moths of Delhi consists of only 74 species (Paul et al. 2017, Paul 2021).

There are limited studies in India that have utilised moth collections preserved in museums and none that have integrated this with primary survey data and secondary data from literature and citizen science projects. In the present work, we have studied the moth collections at National Pusa Collection, Division of Entomology, ICAR-Indian Agricultural Research Institute, New Delhi (NPC-IARI) which is one of the four important Lepidoptera collections in India (Smetacek 2011). NPC houses over 0.4 million specimens, comprising 56000 specimens of Lepidoptera representing 3300 species. NPC has an illustrious history in agriculturally important insect pest collection. Famous lepidopterists such as T.B. Fletcher and Edward Meyrick, worked on these collections prior to India’s independence. However, after independence, there are only a few experts on moths who could visit and work on these collections. In the current study, we studied all the moths that are collected from Delhi housed in NPC-IARI, including our own observations from 2012-2020 and data from different citizen science portals. An illustrated checklist of the 338 moths found in Delhi, along with up-to-date taxonomic treatment, are presented.

Museum specimens

Field surveys

Identification and preparation of checklist