A importância da coloração dinâmica em Morpho helenor (Nymphalidae: Satryrinae) na redução da predação por aves: uma abordagem experimental

Author(s)

Aline Vieira Silva

• Document type: Master's Dissertation
• Press: Campinas, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Instituto de Biologia
• Defense date: 2022-07-07

Examining board members

Paulo Sergio Moreira Carvalho de Oliveira; Rodrigo Cogni; Glauco Machado

• Advisor: Paulo Sergio Moreira Carvalho de Oliveira; André Victor Lucci Freitas

Abstract

Several known antipredator mechanisms involve the color pattern of animal prey. One category of such defense mechanisms that remains unexplored is that of hidden color patterns. This is the case of flash coloration. The flash coloration hypothesis postulates that animals with cryptic coloration, which suddenly display conspicuous coloration during movement, can confuse potential predators and reduce the likelihood of being attacked. To test this hitherto untested hypothesis, we performed unprecedented field experiments using the butterfly Morpho helenor as a model prey species. This butterfly has a contrasting color pattern on the dorsal (blue) and ventral (brown) sides of its wings, resulting in a series of blue "flashes" during flight. Here, we test whether this pattern of flashes during the flight of M. helenor reduces predation by birds in a rainforest from Southeast Brazil. Specifically, we evaluated rates of predation by birds (beak marks on the wings), as well as butterfly survivorship, on treated (altered color pattern) vs control (unaltered color pattern) individuals via mark-recapture censuses. In Experiment 2, we removed the bright blue band on the dorsal wing surface such that the flying M. helenor would always be cryptic in the forest understory for a chasing bird. In Experiment 1, we added a blue band on the ventral wing surface of M. helenor, such that flying butterflies would exhibit the bright blue on both sides of their wings, thus canceling the alternate sequence of crypsis and conspicuousness during flight. In Experiment 3, we evaluated if dead individuals of M. helenor painted with a bright blue band on the ventral wing surface would be more attacked than those with unaltered color pattern when pinned on the forest floor in a resting position. Our results unequivocally show that, by cancelling the protective effect of alternate crypsis and conspicuousness during flight, the probability of survival of treatment M. helenor butterflies (blue band on both wing surfaces) decreases markedly. By cancelling the flash coloration through removal of the dorsal blue band in Experiment 2, both treatment and control butterflies became cryptic during flight, making them equally hard to catch by avian predators and with similar survival rates. The protective value of flash coloration is further corroborated by Experiment 3, which showed that individuals painted with a blue band on the ventral wing surface do not suffer increased predation attempts when landed on the forest floor. Knowledge about the evolution of coloration patterns that vary dynamically during movement is still poorly understood in nature. The current study with M. helenor in Atlantic rainforest is the first to provide experimental evidence that dynamic flash coloration in bright blue Morpho butterflies can be an effective defense mechanism against avian predators (AU)

• FAPESP's process: 20/06756-3 - The importance of the Morpho helenor (Nymphalidae: Morphinae) color pattern in reducing predation by birds: an experimental approach
• Grantee: Aline Vieira e Silva
• Support Opportunities: Scholarships in Brazil - Master