@article {53573, title = {Deaf moths employ acoustic M{\"u}llerian mimicry against bats using wingbeat-powered tymbals}, journal = {Scientific Reports}, volume = {9}, year = {2019}, month = {Jan-12-2019}, abstract = {

Emitting ultrasound upon hearing an attacking bat is an effective defence strategy used by several moth taxa. Here we reveal how Yponomeuta moths acquire sophisticated acoustic protection despite being deaf themselves and hence unable to respond to bat attacks. Instead, flying Yponomeuta produce bursts of ultrasonic clicks perpetually; a striated patch in their hind wing clicks as the beating wing rotates and bends. This wing structure is strikingly similar to the thorax tymbals with which arctiine moths produce their anti-bat sounds. And indeed, Yponomeuta sounds closely mimic such arctiine signals, revealing convergence in form and function. Because both moth taxa contain noxious compounds, we conclude they are mutual M\üllerian acoustic mimics. Yponomeuta\’s perpetual clicking would however also attract bat predators. In response, their click amplitude is reduced and affords acoustic protection just as far as required, matching the distance over which bat biosonar would pick up Yponomeuta echoes anyway \– advanced acoustic defences for a deaf moth.

}, doi = {10.1038/s41598-018-37812-z}, url = {http://www.nature.com/articles/s41598-018-37812-z}, author = {O{\textquoteright}Reilly, Liam J. and Agassiz, David J. L. and Neil, Thomas R.} } @article {53311, title = {The micromechanics and bioacoustic behaviour of Bunaea alcinoe moth scales}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1775 - 1775}, abstract = {

Through the 65 million year acoustic arms race between moths and bats, different moth species have evolved different defence strategies against bat echolocation. For non-toxic moth species without hearing capability, passive acoustic camouflage is thought to be the most efficient way to evade bat predation. Being the elementary building blocks covering moth wing surfaces, scales have been hypothesized as the main organ creating such acoustic camouflage. There is, however, no understanding for the relation between scale microstructure and wing acoustic performance. This report represents the first effort to numerically and experimentally characterize moth scale biomechanics and vibrational behaviour. 3D microstructures of Bunaea alcinoe moth scales have been characterized using various microscopies. A parameterized finite element model has been built to replicate the double-layered perforated scale bio-nanomaterial. Both experimental and numerical analyses have proved that the first three resonance frequencies of a single scale lie within the bat echolocation frequency range. Here, we propose numerical models that explain how the resonances can contribute to the acoustic performance of wings. This study contributes to the on-going discussion of the evolution of ultrasonic camouflage in moths. We aim to use our findings to generate biomimetic light-weight noise mitigation materials.

}, issn = {0001-4966}, doi = {10.1121/1.5067852}, url = {http://asa.scitation.org/doi/10.1121/1.5067852}, author = {Shen, Zhiyuan and Neil, Thomas R. and Daniel Robert and Drinkwater, Bruce W.} } @article {53294, title = {Stealthy moths avoid bats with acoustic camouflage}, journal = {The Journal of the Acoustical Society of America}, volume = {144}, year = {2018}, month = {Jan-09-2018}, pages = {1742 - 1742}, abstract = {

Intense predation pressure from echolocating bats has led to the evolution of a host of anti-bat defences in nocturnal moths. Some have evolved ears to detect the ultrasonic biosonar of bats, yet there are many moths that are completely deaf. To enhance their survival chances, deaf moths must instead rely on passive defences. Here, we show that furry morphological specializations give moth bodies and wing joints acoustic stealth by reducing their echoes from bat calls. Using acoustic tomography, echo strength was quantified in the spatial and frequency domains of two deaf moth species that are subject to bat predation and two butterfly species that are not. Thoracic fur determines acoustic camouflage of moths but not butterflies. Thoracic fur provides substantial acoustic stealth at all ecologically relevant ultrasonic frequencies, with fur removal increasing a moth\’s detection risk by as much as 38\%. The thorax fur of moths acts as a lightweight porous sound absorber, facilitating acoustic camouflage and offering a significant survival advantage against bats.

}, issn = {0001-4966}, doi = {10.1121/1.5067725}, url = {http://asa.scitation.org/doi/10.1121/1.5067725}, author = {Neil, Thomas R. and Shen, Zhiyuan and Drinkwater, Bruce W. and Daniel Robert} }