Mud-puddling of Jay and Emigrants
The Yellow are Common Emigrant
The Common Emigrant or Lemon Emigrant (Catopsilia pomona) is a medium sized pierid butterfly found in Asia and parts of Australia. The species gets its name from its habit of migration. Some early authors considered them as two distinct species Catopsilia crocale and Catopsilia pomona
The Blue is Common Jay
The Common Jay (Graphium doson) is a black, tropical papilionid butterfly with pale blue semi-transparent central wing bands that are formed by large spots. There is a marginal series of smaller spots. The underside of wings is brown with markings similar to upperside but whitish in color. The sexes look alike.
Thanks to Vivek , Naveena and Bala Sir for the confirmation of ID.
Mud-puddling is the phenomenon mostly seen in butterflies and involves their aggregation on substrates like wet soil, dung and carrion to obtain nutrients such as salts and amino acids. This behaviour has also been seen in some other insects, notably the leafhoppers.
Lepidoptera (butterflies and moths) are diverse in their strategies to gather liquid nutrients. Typically, mud-puddling behavior takes place on wet soil. But even sweat on human skin may be attractive to butterflies. The most unusual sources include blood and tears (see below).
This behaviour is restricted to males in many species, and in some like Battus philenor the presence of an assembly of butterflies on the ground acts as a stimulus to join the presumptive mud-puddling flock
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