The evolution of wing shape and movement in bombycoid moths reveals two distinct strategies for agile flight


SOCIETY FOR INTEGRATIVE AND COMPARATIVE BIOLOGY
2021 VIRTUAL ANNUAL MEETING (VAM)
January 3 – Febuary 28, 2021

Meeting Abstract


66-5  Sat Jan 2  The evolution of wing shape and movement in bombycoid moths reveals two distinct strategies for agile flight Aiello, BR*; Sikandar, UB; Minoguchi, H; Kimball, KC; Hamilton, CA; Kawahara, AY; Sponberg, S; Georgia Institute of Technology; University of Idaho; Florida Museum of Natural History baiello3@gatech.edu https://brettaiello.weebly.com/

Flapping flight aerodynamics depends both on wing morphology and movement. However, it is unclear how interspecific variation in wing shape and movement, especially prominent in insects, relates to flight strategy. Previously we examined how wing shape evolved across the phylogenetic split between hawkmoths (Sphingidae) and wild silkmoths (Saturniidae), which have divergent life histories, but agile flight behaviors. Integrating these results with kinematics from two exemplar species and a quasi-steady blade element model, we found evidence that two distinct strategies for agile flight evolved between the clades. Hawkmoths evolved forewing shapes favorable for power reduction and use high frequency wing beats to complete rapid maneuvers. Silkmoths evolved forewing shapes favorable for maneuverability and reduce power using slow high-amplitude wing strokes. To examine if inter-clade differences in kinematic parallel wing shape divergence and extend across the phylogeny, we next collected kinematics in 7 additional species from each family to assess inter-clade aerodynamics. With few exceptions, wing strokes are slow (<20Hz) and high amplitude (127±18 deg.) in silkmoths while rapid (25-70Hz) and low amplitude (106±12 deg.) in hawkmoths, suggesting divergence in wing shape and movement is both correlated and widespread across clades. We suggest that, through selection on both wing shape and movement, performance metrics can be decoupled at evolutionary scales. Finally, these results are integrated into a wider analysis of flight dynamics to explore the correlated evolution of neural and mechanical determinants of flight performance in these diverse agile organisms.

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