DOI: 10.5061/dryad.3ffbg79jp
title: The evolution of two distinct strategies of moth flight

description: Across insects, wing shape and size have undergone dramatic divergence
 even in closely related sister groups. However, we do not know how
 morphology changes in tandem with kinematics to support body weight within
 available power and how the specific force production patterns are linked
 to differences in behavior. Hawkmoths and wild silkmoths are diverse
 sister families with divergent wing morphology. Using 3d kinematics and
 quasi-steady aerodynamic modeling, we compare the aerodynamics and the
 contributions of wing shape, size, and kinematics in 10 moth species. We
 find that wing movement also diverges between the clades and underlies two
 distinct strategies for flight. Hawkmoths use wing kinematics, especially
 high frequencies, to enhance force, and wing morphologies that reduces
 power. Silkmoths use wing morphology to enhance force, and slow, high
 amplitude wingstrokes to reduce power. Both strategies converge on similar
 aerodynamic power and can support similar body mass ranges. However,
 inter-clade within-wingstroke force profiles are quite different and
 linked to the hovering flight of hawkmoths and the bobbing flight of
 silkmoths. These two moth groups fly more like other, distantly related
 insects than they do each other, demonstrating the diversity of flapping
 flight evolution and a rich bio-inspired design space for robotic
 flappers.
description: Live specimens of five different species from each sister-family
 (10 total species). Species from the hawkmoth (Sphingidae) family include:
 Eumorpha achemon, Amphion floridensis, Hyles lineata, Paonias myops, and
 Smerinthus ophthalmica. Species from the silkmoth (Saturniidae) family
 include: Actias luna, Automeris io, Antheraea polyphemus, Hyalophora
 euryalus, and Eacles imperialis. The body and wing
 morphology was digitized for each live specimen using the StereoMorph
 package (version 1.6.2) (2) in R (version 3.4.2; The R Foundation for
 Statistical Computing). The methods are outlined in detail in the
 manuscript methods. Each moth was then recorded by
 three high-speed cameras flying in a wind tunnel. The details of the
 cameras and calibrations are outlined in the methods of the
 text. The data uploaded in this repository include: raw
 kinematic data, raw morphological data, and the images used to digitize
 the morphology of each specimen. In addition, we include flight videos of
 each species, which are all labeled according to the species name. The raw
 kinematic data contains the Fourier Coefficients for every wingstroke of
 every individual of every species used in this study. The corresponding
 equation to evaluate these coefficients is found in the methods section of
 the manuscript. We also include the cofficients for the species-averages
 kinematics of every species. Raw .csv files are also included that contain
 the x, y, and z points of the full wing and body kinematics for every
 species. The columns are all labeled with the appropriate landmark name
 which can be correlated with the methods of the main text. The output data
 from the analysis of all these raw data are all included as supplemental
 data files in the main text.