Mathew and Mohanadas (2001) made a study of insect diversity of Mannavan Shola reporting three hundred and forty four species belonging to 10 orders. Species diversity and richness showed a decreasing trend with increasing altitude. The faunal elements ranged from moist deciduous and evergreen forms to temperate forms in accordance with vegetation and altitude. The faunal composition was interesting as it contained several endemic and protected species. Among butterflies, of the 11 species of endemic butterflies recorded, five species were having protected status in both the areas. Similarly, several butterflies like Vanessa indica, V. cardui (Nymphalidae); Mycalesis oculus (Satyridae); Artogeia canidia (Pieridae) and Telicota acigias (Hesperiidae) are restricted in their distribution. The extent of endemism present in other groups of insects was also high.
Brijesh (2004) in a detailed study on the Lepidoptera of four important shola patches in Munnar viz., Mannavan shola, Pullardi shola, Mantha shola and Pampadum shola, recorded 321 Lepidoptera species under 26 families, of which 89 species (5 families) belonged to the sub order Rhopalocera (butterflies) and the rest belonged to Heterocera (moths). A list of identified species (100 of butterflies, 110 of moths and 23 species belonging to the other groups of insects) are given in Annexures 4 and 5 respectively.
Some of the endemic species of butterflies including Colias nilagiriensis (Pieridae), Mycalesis oculus, Aeromachus pygmaeus (Hesperiidae), Ypthima ceylonica, Ypthima chenui, Ypthima ypthimoides, Cirrochroa thais, Zipoetis satis, Parantica nilgiriensis (Nymphalidae); Udara singalensis, Udara akasa, Curetis thetis (Lycaenidae) were adapted to cool climatic conditions and were shared only by some similar forests like the hills of Nilgiris. The sholas seem to be an ideal habitat for the species Parantica nilgiriensis (Nymphalidae) that is restricted to some of the hills of south India and has been listed as threatened species by IUCN.
Papilio clytia (Papilionidae), Neptis jumbah (Nymphalidae), Castalius rosimon (Lycaenidae) [Schedule I, Part IV]; Appias indira (Pieridae), Athyma ranga, Eriboea athamas, Hypolimnas missipus, Libythea lepita, Zipoetis saitis (Nymphalidae) [Schedule II, Part II]; Euploea core, Euthalia lubentina (Nymphalidae), Appias libythea (Pieridae) [Schedule IV] (Plate II) were some of the protected species under various schedules of the Indian Wildlife Protection Act.