@article {58456, title = {Risk trading in mating behavior: forgoing anti-predatorresponses reduces the likelihood of missing terminalmating opportunities}, journal = {Behavioral Ecology and Sociobiology}, volume = {64}, year = {2010}, pages = {1485-1494}, chapter = {1485}, abstract = {

Life history theory predicts that organisms make certain adjustments to their current and future reproductive effort such that fitness is maximized. Moreover, these adjustments may be fine tuned in response to risks of attack by natural enemies. Thus, we may predict that as an organism ages it will accept increasing levels of exposure to predators during mating activities, effectively trading the risk of losing terminal mating opportunities for the risk of predation. We tested this prediction in an acoustic moth, Achroia grisella, in which females orient toward and evaluate males based on their ultrasonic calling song, and both sexes may be vulnerable to predation by insectivorous bats while in flight as well as on the substrate. In the latter situation, singing males and orienting females show silence and arrestment responses, respectively, when presented with synthetic bat echolocation signals broadcast above a threshold amplitude. We found that both males and females become less sensitive to these broadcasts over the course of their brief reproductive periods, 7 and 5 days, respectively. Over the same periods, sensitivity to male song in both males and females remains constant, and relatively little senescence in sexual behavior is observed. These results support the risk trading hypothesis, and they indicate that life history principles may apply over a very short lifespan.

}, doi = { 10.1007/s00265-010-0963-7}, author = {Marie Lafaille and Ga{\"e}lle Bimbard and Michael D. Greenfield} } @article {58355, title = {Squeaking caterpillars: independent evolution of sonic defense in wild silkmoths}, year = {2020}, doi = {10.1002/ecy.3112}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/ecy.3112}, author = {Sugiura, Shinji and Takanashi, Takuma and Kojima, Wataru and Kajiura, Zenta} } @article {58205, title = {Stridulation of the Garden Tiger Moth, Arctia caja L., audible to the human ear}, year = {1966}, doi = {10.1111/j.1365-3032.1966.tb00337.x}, url = {http://doi.wiley.com/10.1111/j.1365-3032.1966.tb00337.xhttps://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111\%2Fj.1365-3032.1966.tb00337.x}, author = {Rothschild, Miriam and Haskell, P. T.} } @article {58204, title = {[Letters to Editor]}, year = {1877}, doi = {10.1038/015293a0}, url = {http://www.nature.com/articles/015293a0}, author = {WHITE, F. BUCHANAN} } @article {58203, title = {Bats and moths: what is there left to learn?}, year = {2003}, abstract = {

Over 14 families of moths have ears that are adapted to detect the ultrasonic echolocation calls of bats. On hearing a bat, these moths respond with an escape response that reduces their chances of being caught. As an evolutionary response, bats may then have evolved behavioural strategies or changes in call design to overcome the moth\&$\#$39;s hearing. The nature of this interaction is reviewed. In particular, the role of the echolocation calls of bats in the shaping of the structure, neurophysiology and behavioural responses of moths is discussed. Unresolved issues, such as the structural complexity of the moth\&$\#$39;s auditory system, the nature of temporal integration and the role of the non-auditory B cell, are described. Issues in which the interactions between bats and moths may be of more general interest to biologists, such as noise filtering within the central nervous system, protean behaviours and coevolution between predator and prey, are also discussed. The interaction between bats and moths has much to interest general biologists, and may provide a useful model in understanding the neurophysiological basis of behaviour, including protean escape behaviours. The validity of the term coevolution as applied to this system is discussed, as there is no doubt that the auditory system of moths is a response to the echolocation calls of bats, although the evolutionary response of bats to moths is more ambiguous.

}, doi = {10.1111/pen.2003.28.issue-410.1111/j.1365-3032.2003.00355.x}, url = {http://www.blackwell-synergy.com/toc/pen/28/4}, author = {Waters, Dean A.} } @article {58161, title = {Whistling in caterpillars (Amorpha juglandis, Bombycoidea): sound-producing mechanism and function}, year = {2011}, abstract = {

Caterpillar defenses have been researched extensively, and, although most studies focus on visually communicated signals, little is known about the role that sounds play in defense. We report on whistling, a novel form of sound production for caterpillars and rare for insects in general. The North American walnut sphinx (Amorpha juglandis) produces whistle \‘trains\’ ranging from 44 to 2060ms in duration and comprising one to eight whistles. Sounds were categorized into three types: broadband, pure whistles and multi-harmonic plus broadband, with mean dominant frequencies at 15kHz, 9kHz and 22kHz, respectively. The mechanism of sound production was determined by selectively obstructing abdominal spiracles, monitoring air flow at different spiracles using a laser vibrometer and recording body movements associated with sound production using high-speed video. Contractions of the anterior body segments always accompanied sound production, forcing air through a pair of enlarged spiracles on the eighth abdominal segment. We tested the hypothesis that sounds function in defense using simulated attacks with blunt forceps and natural attacks with an avian predator \– the yellow warbler (Dendroica petechia). In simulated attacks, 94\% of caterpillars responded with whistle trains that were frequently accompanied by directed thrashing but no obvious chemical defense. In predator trials, all birds readily attacked the caterpillar, eliciting whistle trains each time. Birds responded to whistling by hesitating, jumping back or diving away from the sound source. We conclude that caterpillar whistles are defensive and propose
that they function specifically as acoustic \‘eye spots\’ to startle predators.

}, keywords = {acoustic communication, Amorpha juglandis, caterpillar, defense, sound production, whistle, yellow warbler}, doi = {10.1242/jeb.046805}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.046805https://syndication.highwire.org/content/doi/10.1242/jeb.046805}, author = {Bura, V. L. and Rohwer, V. G. and Martin, P. R. and Yack, J. E.} } @article {57968, title = {Characteristics of tiger moth (Erebidae: Arctiinae) anti-bat sounds can be predicted from tymbal morphology}, journal = {Frontiers in Zoology}, volume = {16}, year = {2019}, month = {Jan-12-2019}, abstract = {

Background: Acoustic signals are used by many animals to transmit information. Variation in the acoustic characteristics of these signals often covaries with morphology and can relay information about an individual\’s fitness, sex, species, and/or other characteristics important for both mating and defense. Tiger moths (Lepidoptera: Erebidae: Arctiinae) use modified cuticular plates called \“tymbal organs\” to produce ultrasonic clicks which can aposematically signal their toxicity, mimic the signals of other species, or, in some cases, disrupt bat echolocation. The morphology of the tymbal organs and the sounds they produce vary greatly between species, but it is unclear how the variation in morphology gives rise to the variation in acoustic characteristics. This is the first study to determine how the morphological features of tymbals can predict the acoustic characteristics of the signals they produce.

Results: We show that the number of striations on the tymbal surface (historically known as \“microtymbals\”) and, to a lesser extent, the ratio of the projected surface area of the tymbal to that of the thorax have a strong, positive correlation with the number of clicks a moth produces per unit time. We also found that some clades have significantly different regression coefficients, and thus the relationship between microtymbals and click rate is also dependent on the shared ancestry of different species.

Conclusions: Our predictive model allows the click rates of moths to be estimated using preserved material (e.g., from museums) in cases where live specimens are unavailable. This has the potential to greatly accelerate our understanding of the distribution of sound production and acoustic anti-bat strategies employed by tiger moths. Such knowledge will generate new insights into the evolutionary history of tiger moth anti-predator defenses on a global scale.

}, keywords = {Anti-predator defense, bioacoustics, Collections-based research, Lepidoptera, Predictive modeling}, doi = {10.1186/s12983-019-0345-6}, url = {https://frontiersinzoology.biomedcentral.com/articles/10.1186/s12983-019-0345-6}, author = {Dowdy, Nicolas J. and Conner, William E.} } @article {57945, title = {Mechanical tuning of the moth ear: distortion-product otoacoustic emissions and tympanal vibrations}, year = {2013}, abstract = {

The mechanical tuning of the ear in the moth Empyreuma pugione was investigated by distortion-product otoacoustic emissions (DPOAE) and laser Doppler vibrometry (LDV). DPOAE audiograms were assessed using a novel protocol that may be advantageous for non-invasive auditory studies in insects. To evoke DPOAE, two-tone stimuli within frequency and level ranges that generated a large matrix of values (960 frequency\–level combinations) were used to examine the acoustic space in which the moth tympanum shows its best mechanical and acoustical responses. The DPOAE tuning curve derived from the response matrix resembles that obtained previously by electrophysiology, and is V-shaped and tuned to frequencies between 25 and 45 kHz with low Q10dB values of 1.21\±0.26. In addition, while using a comparable stimulation regime, mechanical distortion in the displacement of the moth\’s tympanal membrane at the stigma was recorded with a laser Doppler vibrometer. The corresponding mechanical vibration audiograms were compared with DPOAE audiograms. Both types of audiograms have comparable shape, but most of the mechanical response fields are shifted towards lower frequencies. We showed for the first time in moths that DPOAE have a pronounced analogy in the vibration of the tympanic membrane where they may originate. Our work supports previous studies that point to the stigma (and the internally associated transduction machinery) as an important place of sound amplification in the\ moth ear, but also suggests a complex mechanical role for the rest of the transparent zone.

}, keywords = {Audiogram, DPOAE, Empyreuma pugione, laser Doppler vibrometry, mechanical tuning, moth}, doi = {10.1242/jeb.085902}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.085902https://syndication.highwire.org/content/doi/10.1242/jeb.085902}, author = {Mora, E. C. and Cobo-Cuan, A. and Macias-Escriva, F. and Perez, M. and Nowotny, M. and Kossl, M.} } @article {57906, title = {Keeping up with Bats: Dynamic Auditory Tuning in a Moth}, year = {2006}, abstract = {

Many night-flying insects evolved ultrasound sensi- tive ears in response to acoustic predation by echolo- cating bats [1\–10]. Noctuid moths are most sensitive to frequencies at 20\–40 kHz [6], the lower range of bat ultrasound [5, 11\–13]. This may disadvantage the moth because noctuid-hunting bats in particular echo- locate at higher frequencies shortly before prey cap- ture [7, 11\–13] and thus improve their echolocation and reduce their acoustic conspicuousness [6\–10, 12\–16]. Yet, moth hearing is not simple; the ear\’s non- linear dynamic response shifts its mechanical sensi- tivity up to high frequencies. Dependent on incident sound intensity, the moth\’s ear mechanically tunes up and anticipates the high frequencies used by hunt- ing bats. Surprisingly, this tuning is hysteretic, keep- ing the ear tuned up for the bat\’s possible return. A mathematical model is constructed for predicting a lin- ear relationship between the ear\’s mechanical stiff- ness and sound intensity. This nonlinear mechanical response is a parametric amplitude dependence [17, 18] that may constitute a feature common to other sen- sory systems. Adding another twist to the coevolu- tionary arms race between moths and bats, these re- sults reveal unexpected sophistication in one of the simplest ears known and a novel perspective for inter- preting bat echolocation calls.

}, doi = {10.1016/j.cub.2006.09.066}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0960982206023219}, author = {Windmill, James Frederick Charles and Jackson, Joseph Curt and Tuck, Elizabeth Jane and Robert, Daniel} } @article {57668, title = {The neuroethology of acoustic startle and escape in flying insects}, year = {1989}, abstract = {

The acoustic startle/escape response is a phylogenetically widespread behavioral act, provoked by an intense, unexpected sound. At least six orders of insects have evolved tympanate ears that serve acoustic behavior that ranges from sexual communication to predator detection. Insects that fly at night are vulnerable to predation by insectivorous bats that detect and locate their prey by using biosonar signals. Of the six orders of insects that possess tympanate hearing organs, four contain species that fly at night and, in these, hearing is sensitive to a range of ultrasonic frequencies found in the biosonar signals of bats. Laboratory and field studies have shown that these insects (including some orthopterans, lepidopterans, neuropterans and dictyopterans), when engaged in flight behavior, respond to ultrasound by suddenly altering their flight, showing acoustic startle or negative phonotaxis, which serve as bat-avoidance behavior. A neural analysis of ultrasound-mediated escape behavior was undertaken in the field cricket Telegryllus oceanicus. An identified thoracic interneuron, int-1, was shown to trigger the escape response, but only when the cell was driven (synaptically or electrically) at high spike rates, and only when the insect was performing flight behavior; avoidance steering only occurs in the appropriate behavioral context: flight. Thus, significant constraints operate upon the ability of int-1 to trigger the escape response. The integration of auditory input and flight central pattern generator output occurs in the brain. It is found that neural activity descending from the brain in response to stimulation by ultrasound is increased when the insect is flying compared to when it is not. Although the behavioral act of avoidance steering may appear to be a simple reflex act, further analysis shows it to be anything but simple.

}, author = {Ronald R. Hoy and Nolen, Tom and Brodfuehrer, Peter} } @article {57666, title = {Auditory mechanics and sensitivity in the tropical butterfly Morpho peleides (Papilionoidea, Nymphalidae)}, year = {2009}, abstract = {

The ears of insects exhibit a broad functional diversity with the ability to detect sounds across a wide range of frequencies and intensities. In tympanal ears, the membrane is a crucial step in the transduction of the acoustic stimulus into a neural signal. The tropical butterfly Morpho peleides has an oval-shaped membrane at the base of the forewing with an unusual dome in the middle of the structure. We are testing the hypothesis that this unconventional anatomical arrangement determines the mechanical tuning properties of this butterfly ear. Using microscanning laser Doppler vibrometry to measure the vibrational characteristics of this novel tympanum, the membrane was found to vibrate in two distinct modes, depending on the frequency range: at lower frequencies (1\–5 kHz) the vibration was focused at the proximal half of the posterior side of the outer membrane, while at higher frequencies (5\–20 kHz) the entire membrane contributed to the vibration. The maximum deflection points of the two vibrational modes correspond to the locations of the associated chordotonal organs, suggesting that M. peleides has the capacity for frequency partitioning because of the different vibrational properties of the two membrane components. Extracellular nerve recordings confirm that the innervating chordotonal organs respond to the same frequency range of 1\–20 kHz, and are most sensitive between 2 and 4 kHz, although distinct frequency discrimination was not observed. We suggest that this remarkable variation in structure is associated with function that provides a selective advantage, particularly in predator detection.

}, doi = {10.1242/jeb.032425}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.032425https://syndication.highwire.org/content/doi/10.1242/jeb.032425}, author = {Lucas, K. M. and Windmill, J. F. C. and Robert, D. and Yack, J. E.} } @article {57664, title = {Resonant wing systems in the Australian whistling moth Hecatesia (Agarasidae, Lepidoptera)}, year = {1978}, abstract = {

DARWIN described the sound made by the forewings of the nymphalid Ageronia feronia as a click of a spring catch on a toothed wheel. Descriptions of the sounds produced by the Agarasidae, which have similarly modified forewings, have repeatedly invoked the rubbing of either the antennae or foretibia on the ribbed forewing2,3. Nicholson4 suggested that the production of sound in the whistling moth Hecatesia was percussive, with the knobs of each forewing (castanets) striking each other at the top of the flight stroke. I have confirmed the existence of such a percussive system in two species of Hecatesia. Recordings of H. exultans Walker and H. thyridion Feisthamel from the coastal sand plain of Western Australia revealed two patterns of sound corresponding to the respective flight behaviour of the two species.

}, doi = {10.1038/272444a0}, url = {http://www.nature.com/articles/272444a0}, author = {Winston J. Bailey} } @article {57413, title = {Temporal coding in the auditory receptor of the moth ear}, year = {1988}, abstract = {

Temporal coding in the moth ear was inferred from the response of the auditory receptor to acoustic stimuli with different temporal characteristics.

1.Determinations of the threshold with different stimulus pulse durations showed that the moth ear behaves as an energy detector with a maximum time constant (the integration time) of 25 ms. Pulse durations beyond this value did not result in decreased thresholds (Fig. 1).

2.The synchronization to amplitude modulations was determined by stimulating the moth ear with amplitude modulated (AM) tones (carrier frequency: 40 kHz) and AM white noise presented as 450 ms pulses separated by pauses of similar length. The modulation depth was constant (100\%) whereas the modulation frequency,fm, was varied. The maximumfm which the auditory receptors could follow was 200 Hz (P\<0.05) (Figs. 2, 3, 4).

3.The relatively broad tuning of the only receptor which was functional at the relevant stimulus intensities suggested that AM detection could only be based on temporal cues. This was confirmed by the results showing the same degree of synchronization independent of carrier.

4.A minimum time constant for the receptor was also determined by interrupting a 400 ms noise pulse by a gap (Figs. 5, 6). The threshold for gap detection of the moth ear was ca. 2 ms on a 2.5\% significance level (one sided test).

5.The temporal acuity reported here seems to be fine enough to explain the temporal resolution suggested by behavioral results from other insect species. The results are discussed in relation to acoustic communication in insects as well as in relation to temporal resolution in vertebrates.

}, doi = {10.1007/BF00606123}, url = {http://link.springer.com/10.1007/BF00606123}, author = {Surlykke, Annemarie and Michelsen, Axel} } @article {53574, title = {Wingbeat-generated ultrasound in noctuid moths increases the discharge rate of the bat-detecting A1 cell}, journal = {Proceedings of the Royal Society of London. Series B: Biological Sciences}, volume = {258}, year = {1994}, month = {Oct-10-1995}, pages = {41 - 46}, abstract = {

Some noctuid moths produce ultrasound in flight as a consequence of contact between the distal margins of the hindwings. The sound produced from a conspecific 10 mm from the subject increases the discharge rate of the moth\’s A1 acoustic cell which functions primarily to detect the echolocation calls of bats. Wingbeat sounds are largely ultrasonic, and may provide background noise through which the moth must recognize bat echolocation calls. The sounds may also limit the lower sensitivity of the auditory system. Wingbeat sounds produced appear to be mismatched to the low-frequency hearing of bats which hunt by passive listening, and are unlikely to be a significant aid to passive aerial foraging by bats.

}, issn = {1471-2954}, doi = {10.1098/rspb.1994.0139}, url = {http://www.royalsocietypublishing.org/doi/10.1098/rspb.1994.0139https://syndication.highwire.org/content/doi/10.1098/rspb.1994.0139}, author = {Waters, D.A. and Jones, G.} } @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 {53407, title = {Ultrasonic clicks produced by the peacock butterfly: a possible bat-repellent mechanism}, journal = {Journal of Experimental Biology}, volume = {64}, year = {1976}, pages = {639{\textendash}644}, abstract = {

Torpid peacock butterflies (Inachis io) produce intense ultrasonic clicks that startle captive vespertilionid bats (Plecotus auritus and Pipistrellus pipistrellus). The clicks occur as the wings are opened and are generated by a stiff portion of wing membrane between the costal and subcostal veins near the base of the forewing. The power spectrum of a click matches the most sensitive area of a bat\&$\#$39;s audiogram. Clicks may serve as acoustic equivalents of the attack-retarding eyespot display in the same species.

}, author = {M{\o}hl, Bertel and Lee A. Miller} } @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} } @article {53156, title = {The unique sound production of the Death{\textquoteright}s-head hawkmoth (Acherontia atropos (Linnaeus, 1758)) revisited}, journal = {The Science of Nature}, volume = {102}, year = {2015}, month = {Jan-08-2015}, abstract = {

When disturbed, adults of the Death\’s-head hawkmoth (Lepidoptera, Sphingidae: Acherontia atropos) produce short squeaks by drawing in and deflating air into and out of the pharynx as a defence mechanism. We took a new look at Prell\’s hypothesis of a two-phase mechanism by providing new insights into the functional morphology behind the pharyngeal sound production of this species. First, we compared the head anatomy of A. atropos with another sphingid species, Manduca sexta, by using micro-computed tomography (CT) and 3D reconstruction methods. Despite differences in feeding behaviour and capability of sound production in the two species, the musculature in the head is surprisingly similar. However, A. atropos has a much shorter proboscis and a modified epipharynx with a distinct sclerotised lobe projecting into the opening of the pharynx. Second, we observed the sound production in vivo with X-ray videography, mammography CT and high-speed videography. Third, we analysed acoustic pressure over time and spectral frequency composition of six A. atropos specimens, both intact and with a removed proboscis. Single squeaks of A. atropos last for ca. 200 ms and consist of an inflation phase, a short pause and a deflation phase. The inflation phase is characterised by a burst of ca. 50 pulses with decreasing pulse frequency and a major frequency peak at ca. 8 kHz, followed by harmonics ranging up to more than 60 kHz. The deflation phase is characterised by a less clear acoustic pattern, a lower amplitude and more pronounced peaks in the same frequency range. The removal of the proboscis resulted in a significantly shortened squeak, a lower acoustic pressure level and a slightly more limited frequency spectrum. We hypothesise that the uptake of viscous honey facilitated the evolution of an efficient valve at the opening of the pharynx (i.e. a modified epipharynx), and that sound production could relatively easily have evolved based on this morphological pre-adaptation.

}, keywords = {Insect acoustics, Insect anatomy, Insect head, Manduca sexta, Proboscis, Videography, X-ray imaging}, issn = {0028-1042}, doi = {10.1007/s00114-015-1292-5}, url = {http://link.springer.com/10.1007/s00114-015-1292-5}, author = {Brehm, Gunnar and Fischer, Martin and Gorb, Stanislav and Kleinteich, Thomas and K{\"u}hn, Bernhard and Neubert, David and Pohl, Hans and Wipfler, Benjamin and Wurdinger, Susanne} } @article {53089, title = {What does a butterfly hear? Physiological characterization of auditory afferents in Morpho peleides (Nymphalidae)}, journal = {Journal of Comparative Physiology A}, year = {2018}, month = {May-08-2020}, abstract = {

Many Nymphalidae butterflies possess ears, but little is known about their hearing. The tympanal membrane of butterflies typically comprises distinct inner and outer regions innervated by auditory nerve branches NII and NIII and their respective sensory organs. Using the Blue Morpho butterfly (Morpho peleides) as a model, we characterized threshold and suprathreshold responses of NII and NIII. Both are broadly tuned to 1\–20 kHz with best frequencies at 1\–3 kHz, but NIII is significantly more sensitive than NII. The compound action potentials (CAPs) of both branches increase their first peak amplitudes and areas in response to higher sound levels. NII and NIII differed in their suprathreshold CAP responses to sound frequencies, with stronger responses to 1\–3 and 4\–6 kHz, for NIII and NII respectively; results that are consistent with tympanal membrane mechanics. These results indicate that butterflies are capable of amplitude and frequency discrimination. Both auditory branches responded to playbacks of the flight and calls of predatory birds. We propose that the ears of butterflies, like those of many vertebrate prey such as some rabbits and lizards, function primarily in predator risk assessment.

}, keywords = {Butterfly, Ear, neurophysiology, Predator detection, Sensory}, issn = {0340-7594}, doi = {10.1007/s00359-018-1280-2}, url = {http://link.springer.com/10.1007/s00359-018-1280-2}, author = {Mikhail, Andrew and Lewis, John E. and Yack, Jayne E.} } @article {52672, title = {Hornworm counterattacks: defensive strikes and sound production in response to invertebrate attackers}, journal = {Biological Journal of the Linnean Society}, volume = {123}, year = {2018}, month = {May-18-2018}, pages = {496 - 505}, abstract = {

Caterpillars (i.e. lepidopteran larvae) have evolved multiple defences against predators, with some large caterpillars showing aggressive defences (e.g. strikes and/or sound production). Although such behaviours can startle or warn vertebrate predators, defences against invertebrates remain unclear. We investigated the behavioural responses of the hornworm Langia zenzeroides (Lepidoptera: Sphingidae) against the invertebrate attacker Calosoma maximowiczi (Coleoptera: Carabidae). Fifth (last) instars of L. zenzeroides exhibited a striking response, in which the larva rapidly bent its head and thorax towards the body part stimulated by C. maximowiczi attacks. Strikes were also accompanied by opening of the mandibles, followed by sound production or regurgitation. In some cases, L. zenzeroides larvae caught the legs of C. maximowiczi and threw the beetles using their mandibles. Such counterattacks completely defended against attackers. The sounds that L. zenzeroides generated (pulse durations, 82\–314 ms; dominant frequencies, 5.0\–8.7 kHz; sound pressure level, 44.0\–56.9 dB SPL) were produced by forcing air through the eighth pair of abdominal spiracles. Our results indicate that hornworm larvae are able to deter predacious invertebrates using multiple defences.

}, issn = {0024-4066}, doi = {10.1093/biolinnean/blx156}, url = {https://academic.oup.com/biolinnean/article/123/3/496/4850692}, author = {Sugiura, Shinji and Takanashi, Takuma} } @article {52657, title = {Vocalization in caterpillars: a novel sound-producing mechanism for insects}, journal = {The Journal of Experimental Biology}, volume = {221}, year = {2018}, month = {May-20-20182236}, pages = {jeb169466}, abstract = {

Insects have evolved a great diversity of sound-producing mechanisms largely attributable to their hardened exoskeleton, which can be rubbed, vibrated or tapped against different substrates to produce acoustic signals. However, sound production by forced air, while common in vertebrates, is poorly understood in insects. We report on a caterpillar that \‘vocalizes\’ by forcing air into and out of its gut. When disturbed, larvae of the Nessus sphinx hawkmoth (Sphingidae: Amphion floridensis) produce sound trains comprising a stereotyped pattern of long (370 ms) followed by multiple short-duration (23 ms) units. Sounds are emitted from the oral cavity, as confirmed by close-up videos and comparing sound amplitudes at different body regions. Numerical models using measurements of the caterpillar foregut were constructed to test hypotheses explaining sound production. We propose that sound is generated by ring vortices created as air flows through the orifice between two foregut chambers (crop and oesophagus), a mechanism analogous to a whistling kettle. As air flows past the orifice, certain sound frequencies are amplified by a Helmholtz resonator effect of the oesophagus chamber. Long sound units occur during inflation, while short sound units occur during deflation. Several other insects have been reported to produce sounds by forced air, but the aeroacoustic mechanisms of such sounds remain elusive. Our results provide evidence for this mechanism by showing that caterpillars employ mechanisms similar to rocket engines to produce sounds.

}, keywords = {acoustics, Amphion floridensis, defence, Forced air, Helmholtz resonators, Pulsating jet flows}, issn = {0022-0949}, doi = {10.1242/jeb.169466}, url = {http://jeb.biologists.org/lookup/doi/10.1242/jeb.169466https://syndication.highwire.org/content/doi/10.1242/jeb.169466https://syndication.highwire.org/content/doi/10.1242/jeb.169466}, author = {Rosi-Denadai, Conrado A. and Scallion, Melanie L. and Merrett, Craig G. and Yack, Jayne E.} } @article {52608, title = {Do small ermine moths sing? Possible stridulatory sound production in Yponomeutidae (Lepidoptera)}, journal = {Journal of Natural History}, volume = {51}, year = {2017}, month = {Feb-26-20172086}, pages = {1229 - 1236}, abstract = {

In the hind wings of Yponomeuta and related genera there are transparent patches without scales; within these are arrays of ridges and it is suggested these may be used to produce sounds, with the adjacent membrane acting as a resonator. Avenues for further research are explored, together with potential taxonomic implications.

}, keywords = {hearing, hind wing, sound production, stridulation, Yponomeutidae}, issn = {0022-2933}, doi = {10.1080/00222933.2017.1324063}, url = {https://www.tandfonline.com/doi/full/10.1080/00222933.2017.1324063https://www.tandfonline.com/doi/pdf/10.1080/00222933.2017.1324063}, author = {Agassiz, David J. L.} } @article {48151, title = {Tympanal mechanics and neural responses in the ears of a noctuid moth}, journal = {Naturwissenschaften}, volume = {98}, year = {2011}, month = {Jan-12-2011}, pages = {1057 - 1061}, abstract = {

Ears evolved in many groups of moths to detect the echolocation calls of predatory bats. Although the neurophysiology of bat detection has been intensively studied in moths for decades, the relationship between sound-induced movement of the noctuid tympanic membrane and action potentials in the auditory sensory cells (A1 and A2) has received little attention. Using laser Doppler vibrometry, we measured the velocity and displacement of the tympanum in response to pure tone pulses for moths that were intact or prepared for neural recording. When recording from the auditory nerve, the displacement of the tympanum at the neural threshold remained constant across frequencies, whereas velocity varied with frequency. This suggests that the key biophysical parameter for triggering action potentials in the sensory cells of noctuid moths is tympanum displacement, not velocity. The validity of studies on the neurophysiology of moth hearing rests on the assumption that the dissection and recording procedures do not affect the biomechanics of the ear. There were no consistent differences in tympanal velocity or displacement when moths were intact or prepared for neural recordings for sound levels close to neural threshold, indicating that this and other neurophysiological studies provide good estimates of what intact moths hear at threshold.

}, keywords = {auditory threshold, Lepidoptera, moth auditory biomechanics, neurophysiology}, issn = {0028-1042}, doi = {10.1007/s00114-011-0851-7}, url = {http://link.springer.com/10.1007/s00114-011-0851-7}, author = {ter Hofstede, Hannah M. and Goerlitz, Holger R. and Fernando Montealegre-Zapata and Daniel Robert} } @article {48150, title = {The simple ears of noctuoid moths are tuned to the calls of their sympatric bat community}, journal = {Journal of Experimental Biology}, volume = {216}, year = {2013}, month = {Feb-04-20132149}, pages = {3954 - 3962}, abstract = {

nsects with bat-detecting ears are ideal animals for investigating sensory system adaptations to predator cues. Noctuid moths have two auditory receptors (A1 and A2) sensitive to the ultrasonic echolocation calls of insectivorous bats. Larger moths are detected at greater distances by bats than smaller moths. Larger moths also have lower A1 best thresholds, allowing them to detect bats at greater distances and possibly compensating for their increased conspicuousness. Interestingly, the sound frequency at the lowest threshold is lower in larger than in smaller moths, suggesting that the relationship between threshold and size might vary across frequencies used by different bat species. Here, we demonstrate that the relationships between threshold and size in moths were only significant at some frequencies, and these frequencies differed between three locations (UK, Canada and Denmark). The relationships were more likely to be significant at call frequencies used by proportionately more bat species in the moths\&$\#$39; specific bat community, suggesting an association between the tuning of moth ears and the cues provided by sympatric predators. Additionally, we found that the best threshold and best frequency of the less sensitive A2 receptor are also related to size, and that these relationships hold when controlling for evolutionary relationships. The slopes of best threshold versus size differ, however, such that the difference in threshold between A1 and A2 is greater for larger than for smaller moths. The shorter time from A1 to A2 excitation in smaller than in larger moths could potentially compensate for shorter absolute detection distances in smaller moths.

}, keywords = {allotonic frequency hypothesis, constant-frequency echolocation, horseshoe bats, predator{\textendash}prey interactions, sensory ecology}, issn = {0022-0949}, doi = {10.1242/jeb.093294}, url = {http://jeb.biologists.org/cgi/doi/10.1242/jeb.093294https://syndication.highwire.org/content/doi/10.1242/jeb.093294}, author = {ter Hofstede, H. M. and Goerlitz, H. R. and Ratcliffe, J. M. and Holderied, M. W. and Surlykke, A.} } @article {48140, title = {Hawkmoths produce anti-bat ultrasound}, journal = {Biology Letters}, volume = {9}, year = {2013}, month = {Nov-20-20132082}, pages = {20130161 - 20130161}, abstract = {

Bats and moths have been engaged in aerial warfare for nearly 65 Myr. This arms race has produced a suite of counter-adaptations in moths, including bat-detecting ears. One set of defensive strategies involves the active production of sound; tiger moths\&$\#$39; ultrasonic replies to bat attack have been shown to startle bats, warn the predators of bad taste and jam their biosonar. Here, we report that hawkmoths in the Choerocampina produce entirely ultrasonic sounds in response to tactile stimulation and the playback of biosonar attack sequences. Males do so by grating modified scraper scales on the outer surface of the genital valves against the inner margin of the last abdominal tergum. Preliminary data indicate that females also produce ultrasound to touch and playback of echolocation attack, but they do so with an entirely different mechanism. The anti-bat function of these sounds is unknown but might include startling, cross-family acoustic mimicry, warning of unprofitability or physical defence and/or jamming of echolocation. Hawkmoths present a novel and tractable system to study both the function and evolution of anti-bat defences.

}, keywords = {arms race, bats, echolocation, Sphingidae, sphinx moth}, issn = {1744-9561}, doi = {10.1098/rsbl.2013.0161}, url = {http://rsbl.royalsocietypublishing.org/cgi/doi/10.1098/rsbl.2013.0161https://syndication.highwire.org/content/doi/10.1098/rsbl.2013.0161}, author = {Barber, J. R. and Kawahara, A. Y.} } @article {47652, title = {Hearing sensitivity is more relevant to acoustic conspicuousness than to mechanical constraints in crambid moths}, journal = {Biological Journal of the Linnean Society}, volume = {121}, year = {2017}, month = {May-08-2017}, pages = {174 - 184}, abstract = {

Moths evolved tympanal hearing organs to detect the echolocation calls of predatory bats. Moths\’ auditory responses have been examined mainly for their sensitivity to the frequencies of bat cries: tympanate moths are basically tuned to the call frequencies of sympatric bats. Here, we add the finding that hearing sensitivity to \‘pulse duration\’ in cram- bid moths is also affected by predation pressure from echolocating bats. Analysis of interspecific variation showed that minimum auditory thresholds had a significantly negative relationship with the forewing surface area, that is, acoustic conspicuousness to bat sonar, but no relationship with head width, which was assumed to correlate with tympanal organ size. Auditory thresholds increased as pulses shortened in the 1\–10 ms duration range, and conspic- uous moths with larger wing areas had lower thresholds than smaller moths. By contrast, \‘intraspecific\’ variation, within a single population of the lurcerne moth, revealed no relationship between forewing area and any auditory characteristics. Moth hearing adapts to the echolocation pulse duration of sympatric bat communities, suggesting that evolutionary modification of hearing sensitivity is related to acoustic conspicuousness based on moth wing area.

}, keywords = {arms race, echolocation, predator{\textendash}prey interactions, ultrasound}, issn = {0024-4066}, doi = {10.1093/biolinnean/blw029}, url = {https://academic.oup.com/biolinnean/article-lookup/doi/10.1093/biolinnean/blw029}, author = {Nakano, Ryo and Mason, Andrew C.} } @article {17198, title = {Why do caterpillars whistle at birds? Insect defence sounds startle avian predators}, journal = {Behavioural Processes}, year = {2017}, month = {Jan-02-2017}, issn = {03766357}, doi = {10.1016/j.beproc.2017.02.002}, url = {http://linkinghub.elsevier.com/retrieve/pii/S0376635716303655}, author = {Dookie, Amanda L. and Young, Courtney A. and Lamothe, Gilles and Schoenle, Laura A. and Yack, Jayne E.} } @article {15202, title = {Sound production and hearing in the pyralid moth Symmoracma minoralis}, journal = {Journal of Experimental Biology}, volume = {187}, year = {1994}, pages = {101{\textendash}111}, abstract = {

Males of the moth Symmoracma minoralis (Snellen) (Lepidoptera: Pyralidae, Nymphulinae) were observed producing a high-intensity calling song (95 dB SPL at a distance of 10 cm) with a complex amplitude and frequency modulation (peaks of carrier frequency at 60 and 120 kHz). This sound is produced by a hitherto unknown type of sound organ located in the last abdominal (genital) segment, which may act as a tymbal. The observed directionality of sound output is probably achieved by means of a hollow cone surrounding the sound organ. Electrophysiological recordings revealed that the tympanal organs of S. minoralis are most sensitive in the frequency range from 50 to at least 100 kHz, which is distinctly higher than the minimum threshold levels in most other moths yet examined. The origin of genital sound production is discussed with respect to abdominal pheromone glands and pheromone-releasing movements.

}, url = {http://jeb.biologists.org/content/jexbio/187/1/101.full.pdf}, author = {Klaus-Gerhard Heller and Krahe, R{\"u}diger} } @article {15201, title = {The ultrasonic song of the moth Amyna natalis (Lepidoptera:Noctudidae: Acontiinae)}, journal = {Bioacoustics}, volume = {5}, year = {1993}, pages = {89-97}, chapter = {89}, abstract = {

In Malaysia, males of the noctuid moth Amyna natalis were observed producing a continuous ultrasonic song of high intensity (about 102 dB SPL measured at a distance of 10cm). The frequency spectrum of the sound impulses had its peak between 60 and 80 kHz. During song production the animals were perching on plants and moving their wings up and down quickly. Simultaneously, by twisting the wings it seems likely that a male-specific \“bubble\&$\#$39;\&$\#$39; in the forewing functions as a tymbal, resulting in sound production.

}, doi = {10.1080/09524622.1993.9753231}, url = {http://www.tandfonline.com/doi/abs/10.1080/09524622.1993.9753231}, author = {Klaus-Gerhard Heller and Achmann, Roland} }