About Idea malabarica (Moore, 1877)
The Malabar tree nymph (Idea malabarica) has a wingspan between 120 and 154 mm. It is a mostly white butterfly with black markings. Its upperside is semitransparent white, sometimes slightly darkened by a dusting of black scales. The forewing has the following black markings: narrow margins along both sides of the veins, a dusky streak along the dorsum, large sub-basal spots in interspaces 1 and 2 (the spot in interspace 1 extends further inward), a large oval spot crossing three streaks in the discoidal cell, a spot above this oval spot in interspace 11, a broad margin along the discocellulars, and three rows of spots on the outer half of the wing. On the forewing, the discal series of spots are outwardly conical and curve sharply inward opposite the apex; the subterminal series of spots occur in pairs that coalesce on the veins; the terminal series of spots are elongated on the veins and in the interspaces. The forewing costa has a black streak at its base, with alternating black and white sections beyond the base. The hindwing has similar markings to the forewing: its cell contains two streaks, with the upper streak forked toward the apex; the costa is white, with two spots that do not touch the vein below in interspace 8; paired black spots on veins 5, 7, and 8 do not coalesce, and sit one behind the other. The underside of the wings matches the upperside in pattern. This butterfly has black antennae; its head and thorax are streaked and spotted with black; its abdomen is white, with a broad dusky black streak along the top. A smaller variety called kanarensis (first described by Moore) has identical markings to the standard form, and has been recorded from Konkan and North Kanara. In December 2021, the Malabar tree nymph was declared the state butterfly of Goa, India. This species is listed as Near Threatened on the IUCN Red List, and is threatened by habitat loss caused by deforestation, pesticides, and herbicides. Within India, the species is found across South India, particularly in the Western Ghats. It is endemic to the Western Ghats; while it occurs in southern Maharashtra, its continuous distribution begins at Goa. The larvae of the Malabar tree nymph feed on Aganosma cymosa, a species in the Apocynaceae family. Another Apocynaceae species, Parsonsia spiralis (currently recognized as a synonym of Parsonsia alboflavescens), is also recorded as a larval host plant. It is thought that many more host species from this plant family may be discovered in the future.
