I found this Common Pierrot (Castalius rosimon) butterfly on a quick weed flower (Galinsoga parviflora). I was carrying my Canon EOS 5D Mark III fitted with newly purchased Canon EF 300mm f/4.0 L IS USM + Canon EF 1.4x III Extender. This rig if you remember my older blogs (prior to the purchase of Canon EF 300mm f/2.8L) was one of my favorite rigs for having a versatility of a tele and a reach of a extremely closeup lens. It is an ideal lightweight solution as compared to the cumbersome Canon EF 300mm f/2.8L. I would loose 1 stop of light and the creamy bokeh which was the hallmark of 2.8 lens. But with enough practice it is possible to achieve almost the results of that lens which is over 6 times the price :). The quick weed on which the butterfly was feeding, hardly grows over a feet in height. So the butterfly was close to the ground. I laid myself on my belly to get to the eye level of this beauty. There were several flowers around me with several Plain tigers & Tawny coster butterflies feeding on the nearby flowers. You can faintly see them in the bokeh in most of the photos as a dark silhouettes behind this butterfly.
The Common Pierrot (Castalius rosimon) is a small butterfly found in India that belongs to the Lycaenids or Blues family. It is found in India, and parets of South east Asia. There are two subspecies in India. The common prevalent subspecies in whole of subcontinent south of Himalayas is the nominate Castalius rosimon rosimon Fabricius, 1775 – Continental Common Pierrot & Castalius rosimon alarbus Fruhstorfer, 1922 – Andaman Common Pierrot.
Male has the underside of the wings is white with black spots and streaks. The base of the upper side of both wings is a beautiful shiny pale blue, and more extensive. Upper side is also mainly white. The hind wing has three basal black somewhat coalescent spots overlaid with metallic blue scaling. Fore wing has a long oblique black band from base outwards to the costa and below it, obliquely placed an irregular black somewhat conical. Following these are two outwardly oblique, medially interrupted, black macular bands. There is a seasonal variation in the size and intensity of these black markings; the wet season forms have larger and darker markings than those from the dry season. Female is similar to the male but with the black markings on the upper and under sides broader. The base of the upper side of both wings is a beautiful shiny pale blue, and less extensive. The sub marginal bands above are much wider.
The Dark Pierrot (Tarucus ananda) has similar markings on the underside, but lacks the unmarked gap at the center of the hind wing margin and the central region of the hind wing. On the upperside, it is dark and purplish. The Angled Pierrot (Caleta caleta) and the Banded Blue Pierrot (Discolampa ethion are slightly different, but similar to each other. They have two black bands on the underside of the fore wing at the cell, which form a marking that resembles a ‘V’ In the former, the arms of the ‘V’ are at an angle of 90° and in the latter they are very close to each other and almost parallel. All these species are found in moist deciduous, semi-evergreen and evergreen forests, especially along the forest streams.
A few other species of Pierrots, for example, the Rounded Pierrot (Tarucus nara), cannot be mistaken for this species although they are white marked with black. These species have more than three metallic green spots at the lower corner and hind wing on the underside. However, it is not possible to distinguish between those species in the field because their markings are similar and only the genitalia structures are different These species occur in semi- arid areas or highly disturbed dry forests.
The Common Pierrot is indeed common, especially in open deciduous forests, scrub, grasslands interspersed with trees and near human habitations. It co-occurs with its larval host plants-Ziziphus mauritiana and Z. rugosa. It occurs in lowlands and mid-elevation areas. It is most common during the monsoon but is active in all seasons. Its distributional range extends over the Indian subcontinent and to southeast Asia.
It is a weak flier and it is puzzling how it evades predation by birds. Added to its bright pied coloration is its habit of basking in the sun with its wings half-open, displaying its brilliant metallic green scales on the upperside that make it so conspicuous. It takes short flights, keeps close to the ground and settles every now and then on small herbs and bushes. The flight is weak and fluttering. It avoids thickets or other shaded places and prefers edges and roads in the forests.
The Common Pierrot keeps a look-out for small flowering herbs, such as Altemanthera, Justicia, Sida and Galinsoga(Tridax). Asteraceous flowers are its favorite. Most of the plants from which it sucks nectar have tiny, yellow or white flowers bunched together in inflorescence. It also feeds on dead insects and bird-dnoppings and quenches its thirst on wet soil where many individuals may congregate.
The eggs are laid, one at a time, anywhere on young vegetative shoots of ‘ber’ trees (Ziziphus). They are hemispherical and white with a greenish tinge. The surface is finely reticulated with raised thin lines forming cells, their intersections rising into high round-topped cones with a minute depression on the top of each. The tiny caterpillar stays on the underside of the leaves throughout its life. When young, the caterpillar feeds only on the lower tissues of the leaves, leaving the cuticle intact. Therefore, it is easy to find the caterpillar by looking at young leaves and studying the way in which they are eaten.
The caterpillar is woodlouse-like in shape with its head hidden under the 2nd segment. It is greenish with a dark or faint line or band on the back, from the 2nd to the last segment and two yellowish lines along its sides. However, the caterpillar looks whitish and “frosted” due to the presence of tiny silvery- white hair, which cover the entire body. It moves slowly. Pupation usually takes place on the host plant itself, on the underside of a leaf. The pupa is green or brown with a darker line on the back and a yellowish spiracular line. It is marked with black dots.
Though the caterpillar is occasionally attended to by Prenolepis or other ants with fleeting interest, it is not completely protected against the Chalcid wasp parasitoids. The adult wasps are usually less than a millimetre in total body length and many grow inside a single Common Pierrot caterpillar. The eggs are attacked by extremely tiny Ichneumon wasps, whose larvae eat the content of the egg from within.