Bioacoustic and biophysical analysis of a newly described highly transparent genus of predatory katydids from the Andean cloud forest (Orthoptera: Tettigoniidae: Meconematinae: Phlugidini)

ABSTRACT

Transparency is a greatly advantageous form of camouflage, allowing species to passively avoid detection regardless of the properties of the surface which they occupy. However, it is uncommon and poorly understood in terrestrial species. In one tribe of predacious katydids (Phlugidini), transparency is paired with highly ultrasonic communication for increased predator evasion, yet little is known about the singing capabilities of these species, with only one genus of Phlugidini acoustically well described to date. Here, we describe Speculophlugis hishquten; a new monotypicgenus of highly transparent crystal katy did here named after the infamous Hish-Qu-Ten from the Predator film franchise, discussing the potential use of this species for non-invasive studies of internal anatomy, and analysing its ultrasonic call. Using laser Doppler vibrometry and light microscopy techniques, we found the transparency of the cuticle around the hearing apparatus to be 85–87% at the wavelength of the laser beam (633 nm), making S. hishquten a candidate for the highest recorded cuticle transparency of any insect. The male song has a fundamental frequency of 50 kHz, matching both the ultrasonic call range and rapid call structure of other Phlugidini species. However, the extent of ultrasonic communication and the level of transparency across the Phlugidini tribe requires more attention.

KEYWORDS:

• Camouflage
• bushcricket
• ultrasonic
• stridulatory file
• taxonomy
• neotropical

Acknowledgements

The authors thank Santa Lucia lodge for hospitality during fieldwork. We also thank Thorin Jonsson for developing Matlab code for sound analysis, and Fabio Sarria-S and Ben Chivers for preliminary resonance measurements of the wings using Laser Doppler Vibrometry. Thank you also to two anonymous reviewers who assisted greatly in identifying this species as a monotypic genus.

Author contributions

CW conducted fieldwork, analysed data, wrote the paper, named and diagnosed the genus and species, and prepared figures. CP conducted fieldwork, helped with literature review and writing. DV conducted fieldwork, obtained sound recordings, helped with taxonomic search and made helpful comments to manuscript. FMZ helped to diagnose new species, conducted fieldwork, obtained field and lab recordings, helped with writing and led and provided argument for research.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research resulted from fieldwork of the project ‘The Insect Cochlea’ funded by the European Research Council, Grant ERCCoG-2017-773067 to F. Montealegre-Z. Specimens were collected under Research permit N° 009 - 2018 - IC - FAU - DPAP – (Ecuadorean Ministry of Environment).