4.4. Pinnae in the Pseudophyllinae and Meconematinae It would be sensible to predict, based on these findings, that pseudophyllines which communicate at frequencies beyond the function provided by the acoustic trachea (<60 kHz; Celiker et al., 2020) may have lost function of the trachea, switching instead to utilising the high amplitude gains of the external auditory pinnae (Pulver et al., 2022) for conspecific sound reception (Mason et al., 1991). Morphological data we are collecting as a wider study of katydid auditory systems supports this hypothesis (Woodrow, unpublished). This is likely to also be the case in the extreme ultrasonic Meconematinae (Supersonus and Arachnoscelis spp.), where calling song frequencies range from ~70 kHz over 150 kHz. Wider comparative studies of auditory trachea and pinnae function, combined with numerical simulation and biophysical experimentation, are in process to develop this hypothesis. Funding CW’ s PhD studentship is funded by the University of Lincoln’ s School of Life and Environmental Sciences. This study was funded by a European Research Council Grant ERCCoG-2017-773067 (to FMZ for the project “The Insect Cochlea”) and an NSF - NERC grant NSF DEB-1937815 - NE/T014806/1 (to FMZ). Author contributions CW conducted micro-CT scans, 3D printing, data collection and analysis, and writing. FMZ conducted song recording, specimen collection, permits, supervised, and oversaw the study.

Published as part of Woodrow, Charlie & Montealegre-Z, Fernando, 2023, Auditory system biophysics in a new species of false-leaf katydid (Tettigoniidae: Pseudophyllinae) supports a hypothesis of broadband ultrasound reception, pp. 94-104 in Zoologischer Anzeiger 304 on pages 101-102, DOI: 10.1016/j.jcz.2023.04.002, http://zenodo.org/record/8164300