This Dark Blue Tiger (Tirumala septentorious) butterfly was captured using Canon EF 70-200mm f/2.8L IS II USM on Canon EOS 5DS R. I was at Sammilan Shetty Butterfly Park testing the performance of Canon EOS 5DS R. It was hand held capture at ISO 800 to 1600 as light was low. Flash was not used and very minimal post processing was done. What you are seeing here are around 50% cropped images. Even though cropped, these images are still around 20mega pixels, similar to the size what you get with 5D mark III. Even though it is a poor low light performer 5DS R wins when you are cropping. Canon EF 70-200mm f/2.8L IS II USM is a wonderful lens which is very fast in focusing. Even at f/5.6 aperture, the background goes into a nice and a pleasant blur, which makes the subject which bleedingly sharp to stand out. Even though it is pretty expensive, the money you pay can be seen in its prime lens like sharpness.
Dark Blue Tiger belongs to the crows and tigers, that is, the danaid group of the brush-footed butterfly family. This butterfly shows gregarious migratory behaviour in southern India.
It closely resembles Blue Tiger (Tirumala limniace), but is always sufficiently distinct to be easily recognized, even on the wing. From T. limniace it differs on the upperside in the ground-colour being darker and the bluish markings narrower, more distinct, and of a bluer tint, In the fore wing, in interspace 1 the two streaks are narrower, never joined, the upper one forming an oval detached spot; the short streaks above vein 5 are outwardly never truncate, always acute.
In the hind wing the two streaks if the discoidal cell united at base are wide apart at their apices, the lower one never formed into a hook. On the underside this species is generally darker, the apex of the fore wing and the whole of the ground-colour of the hind wing not being of the conspicuous golden brown that they are in Tirumala limniace.
The butterfly larva generally feed on plants of family Asclepiadaceae from which alkaloids are accumulated in the body. The butterfly carries this toxin thus making it unpalatable to its predators. The recorded host plants are: Vallaris dichotoma, Cosmostigma racemosa, Heterostemma brownii and Cocculus spp.
Eggs are pale white. Caterpillar is orangish white with dark stripes across the body. Pupa is Green with beaded dorsal crescent.
It is found in whole of India, Sri Lanka and some parts of Southeast Asia.