Nature's disguise: Empirical demonstration of dead-leaf masquerade in Kallima butterflies.

Abstract

Animals deploy diverse color-based defenses against predators, including crypsis, mimicry, aposematism, and masquerade. While crypsis, mimicry, aposematism have been extensively studied, the strategy of masquerade-where organisms imitate inedible or inanimate objects such as leaves, twigs, stones, and bird droppings-remains comparatively underexplored, particularly in adult butterflies. The Indian oakleaf butterfly ( Kallima inachus) exemplifies this phenomenon, with its wings resembling dead leaves, providing a classic example of natural selection. Although it has long been postulated that these butterflies evade predation by being misidentified as dead leaves, direct experimental evidence is lacking. In the current study, using domestic chicks as predators, we manipulated their prior experience with dead leaves (model objects) while maintaining constant exposure to butterflies to test whether dead-leaf masquerade provides a protective advantage by preventing recognition. Results showed a marked delay in the initiation of attacks by chicks familiar with dead leaves compared to those with no prior exposure or those exposed to visually altered leaves. Chicks with prior dead-leaf experience required a similar amount of time to attack the butterflies as they did to attack dead leaves. These findings provide the first empirical demonstration of dead-leaf masquerade in Kallima butterflies, shedding light on its evolutionary significance. Our study highlights the effectiveness of masquerade in inducing the misclassification of butterflies as inanimate objects, showcasing the precise mimicry achieved by these organisms when viewed in isolation from the model objects. This study advances our understanding of the evolution of masquerade and its role as a potent antipredator strategy in nature.