The Chestnut Bob (Iambrix salsala salsala)
The Chestnut Bob is a skipper that is widespread in distribution around Singapore. As one of its caterpillar host plants is the ubiquitous "Cow Grass" (Axonopus compressus) that is the main species of grass planted along road verges, school fields and urban garden spaces in Singapore, the butterfly is common. The shot above, taken by ButterflyCircle member Loke PF, features an aberrant Chestnut Bob, which lacks the usual white spots on its wings. Aberrations occur occasionally in some species of butterflies where the markings on the wings are atypical of a standard example of the species.
The shot above shows a typical Chestnut Bob with its usual complement of white spots on both the fore and hindwings, and darker brown patches at the post-discal area of the hindwing. It is not known for certain what processes during the early stages of the butterfly cause the aberration.