The Common Silverline ( spindasis vulcanus ) is a small-sized,colourful butterfly with orange and white bands lined with black on the underside of the wings and prominent black and orange markings on the upper-side. It belongs to the family Lycaenidae, the largest family with more than 6,000 species in the world. This family is often referred to as the ‘Blues’ as a majority of these butterflies have blue uppersides, making Common Silverline one of the exceptions.
A common hedge in our backyards, the ‘Clerodendrum inerme’, popularly known as the Inerme hedge, serves as the primary host plant for the butterfly. The hedge displays clean white flowers with pinkish filaments. This plant is non-native to the Indian Subcontinent but has been widely planted in gardens and in backyards for their ornamental looks.
Butterflies occur in an incredible variety of shapes, colours and patterns. These variations are examples of butterfly evolution. This helps advertise them to potential mates; it also helps them evade predators.
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Butterflies fall prey to a number of predators, including birds, spiders, lizards, small mammals and other insects. Despite being harmless and unable to defend themselves with any sort of aggressive bites or stings, natural selection and certain evolutionary traits have allowed butterflies to adapt and evolve other strategies to better their odds of survival. Their colours and shapes of the wings, and their behaviour in their preferred habitats, help.
Considering the Silverline’s vibrant appearance and visual brilliance, they are extremely susceptible to predatory attacks as most predators depend on vision to find their prey.
The first, and the most important defence mechanism that most butterflies have, is speed. Alertness, combined with enhanced sensitivity to movement, makes butterflies adopt a trait called ‘fright and flight’ to escape any attacks from predators. They don’t have the ‘fight’. The Silverline is adept in swiftness and speed.
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The butterfly also employs a ‘false head’ as a decoy near the base of the hindwing in order to cloud the predator’s judgement on their attack strategies. The hindwing features a prominent ‘eye’ with one or more pairs of threadlike ‘tails’ making them appear like antennae. This fools the predator into attacking the less vital parts of its body like the base of its hindwing, thinking this is the head.
If you have the Inerme hedge in your garden, look for these little orange-red creatures and you just might get lucky to see the life cycle as well.
The writer is the founder of NINOX - Owl About Nature, a nature-awareness initiative. He is the Delhi-NCR reviewer for Ebird, a Cornell University initiative, monitoring rare sightings of birds. He formerly led a programme at WWF India.