Taxonomy and ecology of genus Psyra Walker, 1860 (Lepidoptera: Geometridae: Ennominae) from Indian Himalaya

Abstract

The Psyra Walker, 1860, is a typical Sino-Himalayan genus of the subfamily Ennominae, currently known by 18 species/4 subspecies globally and 9 species from India. This study aims to revise the taxonomy and ecology of Indian Psyra by providing a morphology-based diagnostic key, highlighting their altitudinal, habitat and seasonal preferences, and modelling their distribution based on current and future climatic scenarios. Here, we describe a new species, P. variabilis sp. nov. and document 4 species and 1 subspecies as new to India, viz. P. gracilis, P. szetschwana, P. dsagara, P. falcipennis and P. debilis debilis, thus updating the global species count to 19 with 14 species/1 subspecies from India. We also submitted partial mitochondrial COI sequences of P. crypta, P. similaria, P. spurcataria and P. gracilis as novel to the global genetic database and calculated the overall genetic divergence was 5.17% within the genus, suggesting strong monophyly. Being a typical montane genus, most of the species of Psyra were active within 2000–2280 m altitude, 10.55–15.7°C annual mean temperature, 1200–2300 mm annual precipitation and 168–179 NDVI. Psyra species were predominant in wet temperate, mixed coniferous and moist temperate deciduous forests, their abundance and richness being at peak during post-monsoon months of October–November. The major bioclimatic variables influencing the overall distribution of the genus were mean temperature of warmest quarter, temperature seasonality and precipitation of coldest/driest quarter. While two of the modelled species were predicted to lose area occupancy under future climatic scenarios, the narrow-specialist, Trans-Himalayan species P. debilis debilis was projected to gain up to 75% additional area in the years 2041–60. The results of this study will be helpful to identify sites with maximum area loss projection in ecologically fragile Indian Himalaya and initiating conservation management for such climatically vulnerable insect species groups.