01646nas a2200181 4500008004100000245008100041210006900122520107500191653001301266653001801279653002401297653001101321653001001332653001701342100002501359700002001384856006001404 2019 eng d00aBark beetles use a spring-loaded mechanism to produce variable song patterns0 aBark beetles use a springloaded mechanism to produce variable so3 a

Many insects vary their song patterns to communicate different messages, but the underlying biomechanisms are often poorly understood. Here, we report on the mechanics of sound production and variation in an elytro-tergal stridulator, male Dendroctonus valens bark beetles. Using ablation experiments coupled with high-speed video and audio recordings, we show that: (1) chirps are produced using a stridulatory file on the left elytron (forewing) and a protrusion (plectrum) on the seventh abdominal segment; (2) chirps are produced by ‘spring stridulation’, a catch-and-release mechanism whereby the plectrum catches on a file tooth and, upon release, springs forward along the file; and (3) variability in chirp types is caused by introducing multiple catch-and-release events along the file to create regular interruptions. These results provide experimental evidence for the mechanics of elytro-tergal stridulation, and provide insight into how an insect can incorporate variability into its acoustic repertoire using a spring-loaded mechanism.

10aAcoustic10acommunication10aDendroctonus valens10aInsect10asound10astridulation1 aLindeman, Amanda, A.1 aYack, Jayne, E. uhttp://jeb.biologists.org/lookup/doi/10.1242/jeb.19066001910nas a2200205 4500008004100000022001400041245011800055210006900173260001600242520125400258653001401512653000801526653002001534653002301554653001201577100002001589700002001609700002001629856005501649 2018 eng d a0340-759400aWhat does a butterfly hear? Physiological characterization of auditory afferents in Morpho peleides (Nymphalidae)0 aWhat does a butterfly hear Physiological characterization of aud cMay-08-20203 a

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.

10aButterfly10aEar10aneurophysiology10aPredator detection10aSensory1 aMikhail, Andrew1 aLewis, John, E.1 aYack, Jayne, E. uhttp://link.springer.com/10.1007/s00359-018-1280-202488nas a2200253 4500008004100000022001400041245008000055210006900135260002000204300001400224490000800238520158900246653001401835653002401849653001201873653001501885653002501900653002401925100003001949700002601979700002302005700002002028856018602048 2018 eng d a0022-094900aVocalization in caterpillars: a novel sound-producing mechanism for insects0 aVocalization in caterpillars a novel soundproducing mechanism fo cMay-20-20182236 ajeb1694660 v2213 a

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.

10aacoustics10aAmphion floridensis10adefence10aForced air10aHelmholtz resonators10aPulsating jet flows1 aRosi-Denadai, Conrado, A.1 aScallion, Melanie, L.1 aMerrett, Craig, G.1 aYack, Jayne, E. uhttp://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.16946602180nas a2200145 4500008004100000245010700041210006900148260001600217520166800233100001801901700002801919700002301947700002001970856004401990 2017 eng d00aAcoustic communication in the pine engraver bark beetle: do signals vary between behavioural contexts?0 aAcoustic communication in the pine engraver bark beetle do signa cAug-09-20183 a

Acoustic communication is taxonomically widespread in bark beetles and is proposed to play an important role in a variety of social and defensive behavioural contexts. Yet our understanding of how signals vary between contexts is currently limited. The present study tests the hypothesis that acoustic signals vary between behavioural contexts in the female pine engraver beetle Ips pini (Say) (Coleoptera: Curculionidae: Scolytinae). Female Ips pini produce acoustic chirps using a vertex-pronotal stridulatory organ. Randomly sampled chirps generated under three contexts (i.e. distress, predation and premating) are compared for their duration, number of pulses, interpulse intervals, pulse rate and amplitude envelope shapes. The results obtained show that, during premating events, chirps are significantly longer in duration and tend to have a higher proportion of descending amplitude envelopes than chirps occurring during distress and predation events. Chirps produced during distress and predation conditions are indistinguishable from one another. By contrast to the results from previous bark beetle studies, no support is found for categorizing chirps as ‘interrupted’ or ‘uninterrupted’ types based on temporal patterns. The functional significance of context-dependent variation in chirp characteristics is discussed. Previous studies on acoustic communication in bark beetles are limited as a result of a general lack of objective sampling and measurement criteria for characterizing signals. Recommendations are outlined for future studies on the functions and evolution of acoustic communication in bark beetles.

1 aDobai, Andras1 aSivalinghem, Senthurran1 aGuedes, Raul, N.C.1 aYack, Jayne, E. uhttp://doi.wiley.com/10.1111/phen.1222200562nas a2200157 4500008004100000022001300041245008800054210006900142260001600211100002300227700002400250700002000274700002400294700002000318856006600338 2017 eng d a0376635700aWhy do caterpillars whistle at birds? Insect defence sounds startle avian predators0 aWhy do caterpillars whistle at birds Insect defence sounds start cJan-02-20171 aDookie, Amanda, L.1 aYoung, Courtney, A.1 aLamothe, Gilles1 aSchoenle, Laura, A.1 aYack, Jayne, E. uhttp://linkinghub.elsevier.com/retrieve/pii/S0376635716303655