Analysing diversity patterns of Pyraloidea (Lepidoptera) along the elevational gradient in the East Himalaya of India: Richness, Turnover and range size components

Elevational gradients provide opportunities to study underlying mechanisms shaping community assembly and help to predict ecosystem response to climate change and the impact of local climate on species diversity. Moths with their vast diversity and abundance represent one of the most diverse groups of insects serving significant roles in various ecosystems. Assessing distribution of moths along elevational gradients is important for planning conservation policies. Large elevational gradients are known for their species enrichment capacities making them important conservation hotspots, especially because they can allow for redistribution of species in response to climate change. Herein, we investigate the richness, turnover and range size patterns of Pyraloidea along a mountainous altitudinal gradient of 200m-3500m in the East Himalaya. Sampling was done manually at different altitudinal locations (separated by 500m elevation) with the help of light traps resulting a total of 357 morpho-species of Pyraloidea represented by 14 families. Species richness pattern of Pyraloidea showed a mid-altitudinal peak at 1500m and the highest altitude recording the lowest richness. The species turnover patterns showed peak turnover at the lowest and highest altitude, with lowest turnover value at mid-altitude. However, the altitudinal range size increased with increasing altitudes. Different sub-families reported significant difference in their altitudinal range, with Spilomelinae and Epipaschiinaeare found to be present at every altitude while Lathrotelinae and Galleriinae were restricted at 200 m and 1000 m, respectively. The response of Pyraloidea species to altitude shows that they are sensitive to climatic variables and the results of this study may serve as a baseline for future climate change investigations with Pyraloidea as a model system.