Troides minos, the southern birdwing, also called Sahyadri birdwing, is a large and striking swallowtail butterfly endemic to South India. With a wingspan of 140–190 mm, it is the second largest butterfly of India. It is listed as Least Concern in the IUCN Red List.
It was earlier considered a subspecies of the common birdwing (Troides helena) but is now recognised as a valid species.
The species is more common in the Western Ghats of South India, which is a biodiversity hotspot with a high degree of endemism in many taxa. It is much sought after by collectors and is a highlight of many butterfly tours in the Western Ghats. It is the state butterfly of Karnataka, India.
Further information: External morphology of Lepidoptera
Description from Charles Thomas Bingham (1907) The Fauna of British India, Including Ceylon and Burma, Butterflies. Volume II.
Male and female. Differs from Troides helena cerberus as follows.
Western Ghats and parts of the Eastern Ghats.
The butterfly is locally very common in the southern and central Western Ghats covering the states of Karnataka and Kerala. Also found in southern Maharashtra and northern Goa where it is uncommon. Despite its restricted range and endemicity, the butterfly is not known to be threatened but the IUCN recommends continuous monitoring.
Found up to 3,000 feet (910 m) in the Western Ghats. Found in diverse habitats from low-land evergreen forests near the coast to mixed deciduous forests, dry scrub and agricultural fields.
Active during early morning hours when both sexes feed in the forest on Lantana and diverse food plants. Later on, it is seen sailing as high as 30 to 40 feet (9.1 to 12.2 m) over the countryside until it descends later in the evening to feed again. It flies in a leisurely manner circling around jungle clearings and also frequents hill tops. A determined flier, it is known to cover very large distances before settling. The only food source is nectar, it also visits gardens and orchards and sips from domestic plants such as Mussaenda, Ixora and Lantana.
Though it flies all the year round, it is abundant in the during monsoon and post-monsoon periods.
Spherical eggs laid singly on the edges of the undersides of young leaves and shoots.
Velvety maroon red with shiny black head and four rows of fleshy bright red tubercles. Grey markings on the back with a broad oblique pink white band on the 7th and 8th segments. These are heavily parasitised by tiny braconid wasps.
Pale brown or green, marked with fine brown striations and minute markings. Found on the underside of leaves. If touched, it sways and makes hissing sounds.
Imago (dorsal view)
Imago (ventral view)
The larval host plants of these butterflies are small creepers and climbers of the family Aristolochiaceae such as Aristolochia indica, Aristolochia tagala, Thottea siliquosa and Bragantia wallichii  The host plant toxins sequestered by the butterfly during its larval stage make it unpalatable to predators. Its flight and bright colouration advertise its unpalatability.
Troides minos is a member of the Troides aecus species group. The members of this clade are: