# Tiger beetles produce anti-bat ultrasound and are probable Batesian moth mimics

## TL;DR

Tiger beetles make sounds in response to bat attacks, but these sounds likely mimic unpalatable moths rather than signal their own unpalatability.

## Contribution

Tiger beetles are shown to acoustically mimic unpalatable moths, suggesting Batesian mimicry in bat-insect interactions.

## Key findings

- Tiger beetles produce anti-bat ultrasound in response to echolocation calls.
- Beetle sounds overlap with the warning signals of unpalatable tiger moths.
- Bats consumed most tiger beetles, indicating the beetles are not aposematically signaling.

## Abstract

Echolocating bats and their eared insect prey are in an acoustic evolutionary war. Moths produce anti-bat sounds that startle bat predators, signal noxiousness, mimic unpalatable models and jam bat sonar. Tiger beetles (Cicindelidae) also purportedly produce ultrasound in response to bat attacks. Here we tested 19 tiger beetle species from seven genera and showed that they produce anti-bat signals to playback of authentic bat echolocation. The dominant frequency of beetle sounds substantially overlaps the sonar calls of sympatric bats. As tiger beetles are known to produce defensive chemicals such as benzaldehyde and hydrogen cyanide, we hypothesized that tiger beetle sounds are acoustically advertising their unpalatability. We presented captive big brown bats (Eptesicus fuscus) with seven different tiger beetle species and found that 90 out of 94 beetles were completely consumed, indicating that these tiger beetle species are not aposematically signalling. Instead, we show that the primary temporal and spectral characteristics of beetle warning sounds overlap with sympatric unpalatable tiger moth (Arctinae) sounds and that tiger beetles are probably Batesian mimics of noxious moth models. We predict that many insect taxa produce anti-bat sounds and that the acoustic mimicry rings of the night sky are hyperdiverse.