Avian predation and locomotor mimicry in butterflies of Barro Colorado Island

Authors: Srygley, Robert

Submitted to: Smithsonian Contributions to Botany
Publication Type: Book / Chapter
Publication Acceptance Date: 11/27/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Predation is an important selective force both on butterfly color patterns and on flight performance. Palatable butterflies have short and stout bodies with more massive thoraces that make them more maneuverable and fast flying. Unpalatable species have long thin bodies that make them less maneuverable and slow flying to provide honest signals of their distastefulness. Color pattern mimicry among butterfly species is associated with similarities in wing motion, as well. In Batesian mimicry, the slow wing beat frequency and flight speed of the distasteful models result in a costly signal of their unpalatability and the palatable mimics have an additional cost associated with their dishonest signal. For Mullerian mimics, asymmetry of the wing stroke reliably identifies unpalatable species to particular mimicry groups. Birds are important predators of insects and their abilities to discriminate fine details in motion has resulted in the evolutionary convergence of behavioral traits that humans are unable to see with the unaided eye. Discriminating insects in motion and not pursuing those at rest, the avian hawkers, such as the tyrannids, puffbirds, and jacamars, are likely to be the major agents of selection resulting in precise mimicry and mimicry of motion, in particular.

Technical Abstract: Predation is an important selective force both on butterfly color patterns and on flight performance. Palatable butterflies have short and stout bodies with more massive thoraces that make them more maneuverable and fast flying. Unpalatable species have long thin bodies that make them less maneuverable and slow flying to provide honest signals of their distastefulness. Color pattern mimicry among butterfly species is associated with similarities in wing motion and its aerodynamic costs. In Batesian mimicry, the slow wing beat frequency and flight speed of the distasteful models result in a costly signal of their unpalatability and the palatable mimics have an additional cost associated with their dishonest signal. In Mullerian mimicry, asymmetry of wing motion during the stroke reliably discriminates mimicry groups across behavioral contexts. Discriminating insects in motion and not pursuing those at rest, the avian hawkers, such as the tyrannids, puffbirds, and jacamars, are likely to be the major selective force behind precise mimicry and locomotor mimicry, in particular.