01615nas a2200145 4500008004100000245005200041210005200093260001900145520117200164100002001336700002801356700002501384700001901409856004101428 2012 eng d00aSound reception and radiation in a small insect0 aSound reception and radiation in a small insect aNantes, France3 a

Insects are small; this is a fact of their life. In some contexts this is an advantage, such as insects do not injure themselves through the effects of gravity. In other contexts this is a disadvantage, especially in the context of sound production and reception. The wavelengths of sound that insects such as crickets produce and receive are several times larger than their body size. For sound production, this is particularly challenging and inefficient, as sub-wavelength radiation (size to lambda ratio > 1:100) requires great energy expenditure to produce sufficient sound pressure. In receiving sound, they face the reciprocal problem and are inefficient receivers. In addition,  because of their size they cannot rely on cues other animals use to detect the direction of sound. Nonetheless, sound is extremely important to these insects as they use it for mate attraction and to evade predators. We investigate this problem by combining the technique of microscanning laser Doppler vibrometry with finite element modelling; and explain some of the biomechanical tricks a tiny tree cricket uses to overcome the disadvantages of size.

1 aMhatre, Natasha1 aMontealegre-Z, Fernando1 aBalakrishnan, Rohini1 aRobert, Daniel uhttps://bio.acousti.ca/nl/node/5799102319nas a2200181 4500008004100000245008700041210006900128520167300197653002101870653001201891653001601903653001801919100001501937700002101952700001901973700002501992856012002017 2011 eng d00aMatching sender and receiver: poikilothermy and frequency tuning in a tree cricket0 aMatching sender and receiver poikilothermy and frequency tuning 3 a

Animals communicate in non-ideal and noisy conditions. The primary method they use to improve communication efficiency is sender-receiver matching: the receiver's sensory mechanism filters the impinging signal based on the expected signal. In the context of acoustic communication in crickets, such a match is made in the frequency domain. The males broadcast a mate attraction signal, the calling song, in a narrow frequency band centred on the carrier frequency (CF), and the females are most sensitive to sound close to this frequency. In tree crickets, however, the CF changes with temperature. The mechanisms used by female tree crickets to accommodate this change in CF were investigated at the behavioural and biomechanical level. At the behavioural level, female tree crickets were broadly tuned and responded equally to CFs produced within the naturally occurring range of temperatures (18 to 27°C). To allow such a broad response, however, the transduction mechanisms that convert sound into mechanical and then neural signals must also have a broad response. The tympana of the female tree crickets exhibited a frequency response that was even broader than suggested by the behaviour. Their tympana vibrate with equal amplitude to frequencies spanning nearly an order of magnitude. Such a flat frequency response is unusual in biological systems and cannot be modelled as a simple mechanical system. This feature of the tree cricket auditory system not only has interesting implications for mate choice and species isolation but may also prove exciting for bio-mimetic applications such as the design of miniature low frequency microphones.

10afrequency tuning10ahearing10aOecanthinae10atree crickets1 aMhatre, N.1 aBhattacharya, M.1 aRobert, Daniel1 aBalakrishnan, Rohini uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.057612https://syndication.highwire.org/content/doi/10.1242/jeb.05761203077nas a2200265 4500008004100000245012200041210006900163520220600232653001302438653001202451653002102463653002602484653001502510653001902525653001602544653001202560653001302572100001802585700001502603700001302618700001602631700002502647700001902672856012002691 2013 eng d00aLow-pass filters and differential tympanal tuning in a paleotropical bushcricket with an unusually low frequency call0 aLowpass filters and differential tympanal tuning in a paleotropi3 a

Low-frequency sounds are advantageous for long-range acoustic signal transmission, but for small animals they constitute a challenge for signal detection and localization. The efficient detection of sound in insects is enhanced by mechanical resonance either in the tracheal or tympanal system before subsequent neuronal amplification. Making small structures resonant at low sound frequencies poses challenges for insects and has not been adequately studied. Similarly, detecting the direction of long-wavelength sound using interaural signal amplitude and/or phase differences is difficult for small animals. Pseudophylline bushcrickets predominantly call at high, often ultrasonic frequencies, but a few paleotropical species use lower frequencies. We investigated the mechanical frequency tuning of the tympana of one such species, Onomarchus uninotatus, a large bushcricket that produces a narrow bandwidth call at an unusually low carrier frequency of 3.2 kHz. Onomarchus uninotatus, like most bushcrickets, has two large tympanal membranes on each fore-tibia. We found that both these membranes vibrate like hinged flaps anchored at the dorsal wall and do not show higher modes of vibration in the frequency range investigated (1.5–20 kHz). The anterior tympanal membrane acts as a low-pass filter, attenuating sounds at frequencies above 3.5 kHz, in contrast to the high-pass filter characteristic of other bushcricket tympana. Responses to higher frequencies are partitioned to the posterior tympanal membrane, which shows maximal sensitivity at several broad frequency ranges, peaking at 3.1, 7.4 and 14.4 kHz. This partitioning between the two tympanal membranes constitutes an unusual feature of peripheral auditory processing in insects. The complex tracheal shape of O. uninotatus also deviates from the known tube or horn shapes associated with simple band-pass or high-pass amplification of tracheal input to the tympana. Interestingly, while the anterior tympanal membrane shows directional sensitivity at conspecific call frequencies, the posterior tympanal membrane is not directional at conspecific frequencies and instead shows directionality at higher frequencies.

10aauditory10akatydid10alaser vibrometry10aOnomarchus uninotatus10aOrthoptera10apseudophylline10atettigoniid10atrachea10atympanum1 aRajaraman, K.1 aMhatre, N.1 aJain, M.1 aPostles, M.1 aBalakrishnan, Rohini1 aRobert, Daniel uhttp://jeb.biologists.org/cgi/doi/10.1242/jeb.078352https://syndication.highwire.org/content/doi/10.1242/jeb.07835202670nas a2200229 4500008004100000245013000041210006900171260001600240490000600256520187100262653001402133653001402147653003202161653002102193653002102214653001802235100002202253700001802275700001702293700002502310856010502335 2018 eng d00aAcoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspotAbstract0 aAcoustic indices as rapid indicators of avian diversity in diffe cJan-18-20180 v23 a

Passive acoustic monitoring is a potentially valuable tool in biodiversity hotspots, where surveying can occur at large scales across land conversion types. However, in order to extract meaningful biological information from resulting enormous acoustic datasets, rapid analytical techniques are required. Here we tested the ability of a suite of acoustic indices to predict avian bioacoustic activity in recordings collected from the Western Ghats, a biodiversity hotspot in southwestern India. Recordings were collected at 28 sites in a range of land-use types, from tea, coffee, and cardamom plantations to remnant forest stands. Using 36 acoustic indices we developed random forest models to predict the richness, diversity, and total number of avian vocalizations observed in recordings. We found limited evidence that acoustic indices predict the richness and total number of avian species vocalizations in recordings (R2 < 0.51). However, acoustic indices predicted the diversity of avian species vocalizations with high accuracy (R2 = 0.64, mean squared error = 0.17). Index models predicted low and high diversity best, with the highest residuals for medium diversity values and when continuous biological sounds were present (e.g., insect sounds >8 sec). The acoustic complexity index and roughness index were the most important for predicting avian vocal diversity. Avian species richness was generally higher among shade-grown crops than in the open tea plantation. Our results suggest that models incorporating acoustic indices can accurately predict low and high avian species diversity from acoustic recordings. Thus, ecoacoustics could be an important contributor to biodiversity monitoring across landscapes like the Western Ghats, which are a complex mosaic of different land-use types and face continued changes in the future.

10adiversity10alandscape10apassive acoustic monitoring10ashade-grown crop10aspecies richness10aWestern Ghats1 aAgnihotri, Samira1 aRobin, V., V.1 aGoel, Anurag1 aBalakrishnan, Rohini uhttps://www.veruscript.com/journals/journal-of-ecoacoustics/acoustic-diversity-in-an-indian-hotspot/01743nas a2200157 4500008004100000022001300041245007800054210006900132260001600201300001400217490000700231520123200238100002501470700002401495856006601519 1996 eng d a0003347200aRecognition of courtship song in the field cricket,Teleogryllus oceanicus0 aRecognition of courtship song in the field cricketTeleogryllus o cJan-02-1996 a353 - 3660 v513 a

The courtship song of the cricket,Teleogryllus oceanicusplays an important role in inducing the female to mount the male, which is necessary for mating. The song consists of a short, amplitude-modulated chirp, followed by a long trill of constant intensity and high syllable rate. Using playback techniques, it was determined which physical parameters of courtship song are necessary and/or sufficient to evoke normal female mounting of muted, courting males. The higher harmonics of natural courtship song were neither necessary nor sufficient for the effectiveness of the song. The chirp component alone was sufficient to evoke normal levels of mounting, but the trill was only partially effective on its own. The conspicuous amplitude modulation of the chirp was not necessary to evoke normal responses. The results suggest that the high effectiveness of the chirp is due to its characteristic temporal pattern. As in other cricket species, the song repertoire ofT. oceanicusalso includes distinct calling and aggression songs, which contain chirps that are structurally similar to the courtship chirp. Both calling and aggression songs evoked normal mounting responses when played back in the context of courtship.

1 aBalakrishnan, Rohini1 aPollack, Gerald, S. uhttp://linkinghub.elsevier.com/retrieve/pii/S0003347296900342