Tawny Coster

I saw this Tawny Coster (Acraea terpsicore) butterfly on a dry twig on the same evening I was photographing kites I wrote about in my last blog.

I was carrying my Canon EOS 5D mark II fitted with Canon EF 300mm f/2.8 L IS USM + Canon EF 2X II Extender. This 600mm rig was used to take this macro shot. This 300mm f/2.8 lens without extender gives magnification of 0.13X at MFD (Minimum Focus Distance) of 2.5m (8.2 feet). Extenders do not affect the Minimum Focus Distance of the lens they are mounted behind, thus the MM (Maximum Magnification) of the lens is also multiplied. So with 2X Extender I get .26x magnification at the same MFD. Even though it is not as great as having 1:1 magnification of dedicated macro lens, but is close enough get good closeup photography.

I was using my Benro C45T Carbon Fiber Monopod to support this heavy rig. To get better depth of field I first chose f/8.0 which still seemed shallow. Only at f/11 aperture the depth of field was sufficient. You can notice a very smooth bokeh in the background. The green fountain grasses are all out of focus. I could not get the beautiful frontal light from the setting sun you see in the first photo in my other two photos as cloud had covered the sun and made the lighting more diffuse.

The Tawny Coster (Acraea terpsicore) is a small leathery winged butterfly which is common in grassland and scrub habitats. It belongs to the Nymphalidae or brush-footed butterfly family. It has a weak fluttery flight. It is avoided by most insect predators as it contains poisonous alkaloids in its body. Tawny Coster and the Yellow Coster (Acraea issoria) are the only two Indian spcies of the predominantly African tribe Acraeini.

Major taxonomic misidentification which still causes confusion today. Tawny Coster was described as Papilio terpsicore by Linnaeus in 1758. It was held to be the senior synonym of Acraea serena, described by Fabricius as Papilio serena in 1775. Hence, the former name was commonly used for that African species. But as it turned out, Linnaeus had actually described an Indian species — the well-known Tawny Coaster. Fabricius in 1793 believed it was new to science and described it again, as Papilio violae. Consequently it had been long known as Acraea violae.

The color Tawny referres to an yellowish brown color. The word means “tan-colored,” from Anglo-French tauné “associated with the brownish-yellow of tanned leather,” from Old French tané “to tan hides,” from Medieval Latin tannare from tannum “crushed oak bark,” used in tanning leather, probably from a Celtic source (e.g. Breton tann “oak tree”).

The Tawny Coster butterfly is found in India and Sri Lanka. It is common all the year round and is equally at home in forest clearings and open country. Though mainly seen at low elevations it has been recorded at heights of up to 7,000 feet (2,100 m) in south India and sometimes in the North. It is plentiful in the pre-monsoon and monsoon period and becomes scarce later on.

The butterfly exudes an oily and smelly yellow liquid when handled and is unpalatable to birds and most insects. They are well protected and have a slow and weak flight, frequently visiting flowers. There are no mimics in India. Sexes both look alike with few minor variation.

The butterfly breeds on plants of the family Loganiaceae and species of Passiflora many of which contain toxins that are sequestered by the caterpillars.

Larva is Cylindrical, slender, with six longitudinal rows of fine branched spines; colour reddish brown with an oily gloss, much paler on the head, second and last segment; an unwholesome looking insect, doubtless protected like the butterfly. Pupa is perpendicularly hung, long, slender, smooth; two lateral angles on the thorax; head quadrate; color creamy white, with broad longitudinal bars of purplish-black spotted with orange.