Assessment of insect diversity along an altitudinal gradient in Pinderi forests of Western Himalaya, India

Insect diversity, richness and abundance were evaluated at different altitudes in three forest habitats in the Western Himalayas. The habitats studied were all situated between 2100 and 3500 m and included a site with no disturbances, a site with a moderate level of disturbance and a site with a very high level of disturbance. The species composition and diversity of insects varied at all the three study sites, which demonstrates the effect of altitude and disturbances, as well as the effects of other ecological and climatic parameters on insect populations. The site at lowest altitude, which contained a moderate level of disturbance, supported the highest number of species (108), whereas the site at the highest altitude, which contained the maximum level of disturbance, supported the lowest number of species (77). When all of the sites were considered, 122 species of insects belonging to 43 families and 8 orders were recorded. Lepidoptera was the most dominant insect order recorded, with 46 species being observed. This was followed by Hymenoptera (20), Coleoptera (18), Orthoptera (12), Hemiptera (10), Odonata (9), Diptera (5) and Dermeptera (2). The most abundant species were Vanessa cashmirensis Fru. (Lepidoptera: Nymphalidae), Pieris canidia indica Sparr. (Lepidoptera: Pieridae), Apis laboriosa Smith (Hymenoptera: Apidae), Anomala dimidiata Hope (Coleoptera: Scarabidae), Chorthipus sp. (Orthoptera: Acrididae), Crocothemis servilia servilia (Drury) (Odonata: Libellulidae) and Syrphus fulvifacies Brunetti (Diptera: Syrphidae). The site at the lowest altitude and the sites with the longest rainy seasons had the highest Shannon–Wiener Diversity.