DOCSLIB.ORG

Changing Resonator Geometry to Boost Sound Power Decouples Size And

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Changing Resonator Geometry to Boost Sound Power Decouples Size And Changing resonator geometry to boost sound power PNAS PLUS decouples size and song frequency in a small insect Natasha Mhatrea,1, Fernando Montealegre-Za, Rohini Balakrishnanb, and Daniel Roberta aSchool of Biological Sciences, Woodland Road, University of Bristol, Bristol BS8 1UG, United Kingdom; and bCentre for Ecological Sciences, Indian Institute of Science, Bangalore 560012, India Edited by A. J. Hudspeth, Howard Hughes Medical Institute, New York, NY, and approved March 28, 2012 (received for review January 6, 2012) Despite their small size, some insects, such as crickets, can produce by the pallets allows the gear to move forward only once every high amplitude mating songs by rubbing their wings together. By oscillation by mechanically blocking its motion at other times. exploiting structural resonance for sound radiation, crickets broad- Hence, the frequency at which the gear tooth engages and im- cast species-specific songs at a sharply tuned frequency. Such songs parts force back to the pendulum is set by the pendulum itself enhance the range of signal transmission, contain information (8). Cricket wings play the same role as the pendulum by deter- about the signaler’s quality, and allow mate choice. The production mining the dominant or carrier frequency (CF) of the cricket’s of pure tones requires elaborate structural mechanisms that con- song (5, 6), and the file and plectrum are the analogs of the gear trol and sustain resonance at the species-specific frequency. Tree and pallets parts of the escapement mechanism prompting the crickets differ sharply from this scheme. Although they use a reso- term “clockwork cricket” (5, 7). In the absence of such an esca- nant system to produce sound, tree crickets can produce high am- pement mechanism, the CF of a cricket song would be variable, plitude songs at different frequencies, varying by as much as an and their wings would be much less efficient at producing high octave. Based on an investigation of the driving mechanism and amplitude mate attraction signals (2). the resonant system, using laser Doppler vibrometry and finite ele- Crickets are poikilothermic animals, and their physiology is ment modeling, we show that it is the distinctive geometry of the greatly affected by changes in ambient temperature as is their crickets’ forewings (the resonant system) that is responsible for song (10–13). In field crickets, where the escapement system is their capacity to vary frequency. The long, enlarged wings enable best studied, the song CF changes very little with temperature BIOPHYSICS AND the production of high amplitude songs; however, as a mechanical (6). As the resonant frequency of the wings does not change with consequence of the high aspect ratio, the resonant structures have temperature, it was proposed that the plectrum cannot proceed COMPUTATIONAL BIOLOGY multiple resonant modes that are similar in frequency. The drive along the file any faster despite the overall change in the speed of produced by the singing apparatus cannot, therefore, be locked the wing-stroke (5, 6). As a result, the song CF does not change, to a single frequency, and different resonant modes can easily be and crickets can produce high amplitude, pure-tone signals re- engaged, allowing individual males to vary the carrier frequency of gardless of ambient temperature (6). their songs. Such flexibility in sound production, decoupling body Another implication of this deterministic mechanical model of size and song frequency, has important implications for conven- sound production is that there is an inflexible relationship be- tional views of mate choice, and offers inspiration for the design tween body size and song CF within a species of cricket (4, 14, of miniature, multifrequency, resonant acoustic radiators. 15); hence, CF is an obligatorily honest signal of an individual’s size. Moreover, all insects that use similar sound production me- bioacoustics ∣ biological modelling ∣ biomechanics ∣ finite element analysis chanisms such as katydids (tettigoniids) and field crickets (gryl- lids), were expected to follow this pattern (4). Earlier research showed that females prefer males broadcasting lower CF songs; ale crickets produce high amplitude calling songs to attract – Mconspecific females (1, 2). The sounds are produced by stri- hence, females choose larger and potentially fitter males (16 18). dulation, a rapid and controlled rubbing of forewings against each The generality of this mechanism for female choice has been other. The plectrum, a sclerotized portion on the anal edge of one challenged in birds and mammals (19, 20) but not in insects. Ex- wing, is drawn across the file, a series of teeth on the underside of amples of uncoupling CF from size is rare in insects; yet, a notable a vein, on the other wing (reviewed in ref. 3). The stridulatory exception are the Oecanthines, or tree-crickets, whose calling apparatus acts as a mechanical frequency-multiplying system, song CF varies greatly with temperature (10, 21, 22). converting the slow wing-stroke rate (ca 30 Hz) of the insect into Tree crickets (Oecanthinae, Gryllinae, Orthoptera) are distin- guished by beautiful, transparent wings that are conspicuously en- a sound of much higher frequency (e.g., 4.5 kHz in the field crick- – et Gryllus bimaculatus) (3, 4). Stridulation sets the wing into larged with respect to their body size (22 25). Little is known, vibration, and if the frequency produced by the plectrum-file in- however, about the relationship between temperature, the stridu- teraction (the tooth strike rate) matches the resonance frequency latory mechanism, and wing resonances in Oecathines (23, 26). of the wings a higher amplitude pure-tone sound can be produced Even less is known about the evolutionary reasons for their re- (2). The exact biophysical mechanisms enabling such sound ra- markable wings and the consequences of having sound radiators diation using soft structures many times smaller than the sound that are so different from those of the previously studied field crickets (27, 28) and katydids (29, 30). wavelength remain elusive. The key outstanding question pertains to the mechanism that The mechanism that crickets use to match stridulatory fre- enables the production of variable frequency songs that are high quency to resonant frequency is similar to a clockwork-like esca- amplitude and tonal. We dissect the relationship between the pement system (5–7). In the field of horology, escapement mechanisms display different degrees of sophistication (8), one is even called the grasshopper escapement (9). The fundamental Author contributions: N.M., F.M.-Z., R.B., and D.R. designed research; N.M. and F.M.-Z. principle of an escapement can, however, be illustrated by the performed research; N.M. and F.M.-Z. analyzed data; and N.M. wrote the paper. simple deadbeat escapement. In a deadbeat escapement, the re- The authors declare no conflict of interest. sonant system is a pendulum that acts as a regulator and sets the This article is a PNAS Direct Submission. speed at which the mechanism oscillates. The force comes from a 1To whom correspondence should be addressed. E-mail: [email protected]. rotating gear whose teeth engage and apply force to pallets at- This article contains supporting information online at www.pnas.org/lookup/suppl/ tached to the pendulum. The sequential release of the gear teeth doi:10.1073/pnas.1200192109/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1200192109 PNAS Early Edition ∣ 1of9 Downloaded by guest on September 30, 2021 forces generated by the stridulatory mechanism, and the resonant changes over time (7). Alternatively, if the two envelopes corre- behavior, size and shape of the acoustic radiators. The results re- spond exactly, it is expected that the HF elements are a product of veal that the ability to produce variable frequencies is determined harmonic distortion and not produced by the stridulatory appa- by morphological geometry; i.e., the high aspect ratio of the re- ratus. We found that the envelope of the HF ticking sound was sonator. The results also suggest that the evolution of this wing different from that of the CF sound as can be observed in the time morphology is driven by the need to produce higher amplitude resolved gain between the unfiltered and filtered syllables over a mate attraction songs, and the variable frequency is an inevitable range of temperatures (Fig. 1). Remarkably, the temporal dy- outcome. In biophysical terms, the results uncover a remarkably namics of instantaneous frequency and HF components change simple method to design efficient resonators with variable fre- with temperature (Fig. 1). quency output. The other interesting outcome vis a vis sexual se- lection is that it negates the idea that insects are obliged to signal Modeling the Stridulatory Apparatus. Having found evidence for an their body size honestly as a result of their inflexible sound pro- escapement mechanism in O. henryi songs, the next step was to duction mechanism. probe the nature of the mechanical drive imparted to the wings. Three models of the forces that developed during the closing Results stroke of stridulation were generated. Each model had a different The “Ticking” in Tree-Cricket Song. It has been suggested that if stri- force regime: a sinusoidal drive, an impulsive drive, and a “catch dulation relies on an escapement mechanism, the plectrum will and release “drive (Fig. 2A). The latter two have been the domi- make a high frequency ‘ticking’ sound as it engages each tooth of nant models in describing an escapement system in field cricket the file (7). The ticking that is produced is soft; yet, it is expected stridulatory behavior (6, 31). to produce small irregularities in the acoustic waveform. Close With all three models, because there is a net positive force on examination of song recordings made in the field from the South each wing through time, a net forward movement of the plectrum Indian tree cricket Oecanthus henryi (22) reveals the presence of along the file will be produced (Fig.
Load more

Recommended publications
  • AND BODY of CICADA": IMPRESSIONS of the LANTERN-FLY (HEMIPTERA: FULGORIDAE) in the VILLAGE of Penna BRANCA" BAHIA STATE, BRAZIL
    Journal of Ethnobiology 23-46 SpringiSummer 2003 UHEAD OF SNAKE, WINGS OF BUTTERFL~ AND BODY OF CICADA": IMPRESSIONS OF THE LANTERN-FLY (HEMIPTERA: FULGORIDAE) IN THE VILLAGE OF PEnnA BRANCA" BAHIA STATE, BRAZIL ERALDO MEDEIROS COSTA-NElO" and JOSUE MARQUES PACHECO" a Departtll'rtl?nto de Cit?t1Cias BioMgicasr Unh:rersidade Estadual de Feira de Santana, Km 3, BR 116, Campus Unirl£rsitario, eEP 44031-460, Ferra de Santana, Bahia, Brazil [email protected],br b DepartmHemo de Biowgifl Evolutim e Ecologia, Unit:rersidade Federal de Rod. Washington Luis, Km 235, Caixa Postal 676, CEP 13565~905, Sao Silo Paulo, Brazil r:~mail: [email protected] To the memory of Darrell Addison Posey (1947-2001) ABSTRACT.-Four aspects of the ethnoentomology of the lantern-fly (Fulgora la­ temari" L., 1767) were studied in Pedra Branca, Brazil. A total of 45 men and 41 women were consulted through open-ended interviews and their actions were observed in order to document the wisdom, beliefs, feelings, and behaviors related to the lantern-fly. People/s perceptions of the ex.temal shape of the insect influence its ethnotaxonomy, and they may categorize it into five different ethnosemantic domains, VilJagers a.re familiar with the habitat and food habits of the lantern- fly; they it lives on the trunk of Simarouba sp. (Simaroubaceae} by feeding on sap with aid of its 'sting: The culturally constructed attil:tldes toward this insect are that it is a fearsome organism that should be extlimninated .vhenever it is found because it makes 'deadly attacks.' on plants and human beings.
    [Show full text]
  • Young Naturalists Teachers Guides Are Provided Free of Charge to Classroom Teachers, Parents, and Students
    MINNESOTA CONSERVATION VOLUNTEER Young Naturalists Prepared by “Buggy Sounds of Summer” Jack Judkins, Multidisciplinary Classroom Activities Department of Education, Teachers guide for the Young Naturalists article “Buggy Sounds of Summer,” by Larry Weber. Illustrations by Taina Litwak. Published in the July–August 2004 Conservation Bemidji State Volunteer, or visit www.dnr.state.mn.us/young_naturalists/buggysounds University Young Naturalists teachers guides are provided free of charge to classroom teachers, parents, and students. This guide contains a brief summary of the articles, suggested independent reading levels, word counts, materials list, estimates of preparation and instructional time, academic standards applications, preview strategies and study questions overview, adaptations for special needs students, assessment options, extension activities, Web resources (including related Conservation Volunteer articles), copy-ready study questions with answer key, and a copy-ready vocabulary sheet. There is also a practice quiz (with answer key) in Minnesota Comprehensive Assessments format. Materials may be reproduced and/or modified a to suit user needs. Users are encouraged to provide feedback through an online survey at www. dnr.state.mn.us/education/teachers/activities/ynstudyguides/survey.html. Note: this guide is intended for use with the PDF version of this article. Summary “Buggy Sounds of Summer” introduces readers to crickets, katydids, and cicadas, three insects that make sounds with specialized body parts. Through photos,
    [Show full text]
  • Animal Bioacoustics
    Sound Perspectives Technical Committee Report Animal Bioacoustics Members of the Animal Bioacoustics Technical Committee have diverse backgrounds and skills, which they apply to the study of sound in animals. Christine Erbe Animal bioacoustics is a field of research that encompasses sound production and Postal: reception by animals, animal communication, biosonar, active and passive acous- Centre for Marine Science tic technologies for population monitoring, acoustic ecology, and the effects of and Technology noise on animals. Animal bioacousticians come from very diverse backgrounds: Curtin University engineering, physics, geophysics, oceanography, biology, mathematics, psychol- Perth, Western Australia 6102 ogy, ecology, and computer science. Some of us work in industry (e.g., petroleum, Australia mining, energy, shipping, construction, environmental consulting, tourism), some work in government (e.g., Departments of Environment, Fisheries and Oceans, Email: Parks and Wildlife, Defense), and some are traditional academics. We all come [email protected] together to join in the study of sound in animals, a truly interdisciplinary field of research. Micheal L. Dent Why study animal bioacoustics? The motivation for many is conservation. Many animals are vocal, and, consequently, passive listening provides a noninvasive and Postal: efficient tool to monitor population abundance, distribution, and behavior. Listen- Department of Psychology ing not only to animals but also to the sounds of the physical environment and University at Buffalo man-made sounds, all of which make up a soundscape, allows us to monitor en- The State University of New York tire ecosystems, their health, and changes over time. Industrial development often Buffalo, New York 14260 follows the principles of sustainability, which includes environmental safety, and USA bioacoustics is a tool for environmental monitoring and management.
    [Show full text]
  • “Can You Hear Me?” Investigating the Acoustic Communication Signals and Receptor Organs of Bark Beetles
    “Can you hear me?” Investigating the acoustic communication signals and receptor organs of bark beetles by András Dobai A thesis submitted to the Faculty of Graduate and Postdoctoral Affairs in partial fulfillment of the requirements for the degree of Master of Science In Biology Carleton University Ottawa, Ontario © 2017 András Dobai Abstract Many bark beetle (Coleoptera: Curculionidae: Scolytinae) species have been documented to produce acoustic signals, yet our knowledge of their acoustic ecology is limited. In this thesis, three aspects of bark beetle acoustic communication were examined: the distribution of sound production in the subfamily based on the most recent literature; the characteristics of signals and the possibility of context dependent signalling using a model species: Ips pini; and the acoustic reception of bark beetles through neurophysiological studies on Dendroctonus valens. It was found that currently there are 107 species known to stridulate using a wide diversity of mechanisms for stridulation. Ips pini was shown to exhibit variation in certain chirp characteristics, including the duration and amplitude modulation, between behavioural contexts. Neurophysiological recordings were conducted on several body regions, and vibratory responses were reported in the metathoracic leg and the antennae. ii Acknowledgements I would like to thank my supervisor, Dr. Jayne Yack for accepting me as Master’s student, guiding me through the past two years, and for showing endless support and giving constructive feedback on my work. I would like to thank the members of my committee, Dr. Jeff Dawson and Dr. John Lewis for their professional help and advice on my thesis. I would like to thank Sen Sivalinghem and Dr.
    [Show full text]
  • The Neuromuscular Mechanism of Stridulation in Crickets (Orthoptera: Gryllidae)
    J. Exp. Biol. (1966), 45, isi-164 151 With 8 text-figures Printed in Great Britain THE NEUROMUSCULAR MECHANISM OF STRIDULATION IN CRICKETS (ORTHOPTERA: GRYLLIDAE) BY DAVID R. BENTLEY AND WOLFRAM KUTSCH Department of Zoology, University of Michigan, Aim Arbor, and Institute for Comparative Animal Physiology, University of Cologne {Received 21 February 1966) INTRODUCTION Study of the insect neuromuscular system appears very promising as a means of explaining behaviour in terms of cellular operation. The relatively small number of neurons, the ganglionic nature of the nervous system, the simplicity of the neuro- muscular arrangement, and the repetitiveness of behavioural sequences all lend them- selves to a solution of this problem. As a result, an increasing number of investigators have been turning their attention to insects and especially to the large orthopterans. Recently, Ewing & Hoyle (1965) and Huber (1965) reported on muscle activity underlying sound production in crickets. The acoustic behaviour is well understood (Alexander, 1961) and in the genera Gryllus, Acheta and Gryllodes communication is mediated by three basic songs composed of three types of pulses. While working independently on this system at the University of Cologne (W.K.) and the University of Michigan (D.B.) using various Gryllus species, we found a number of basic differences between the muscle activity in our crickets and that reported by Ewing & Hoyle (1965) for Acheta domesticus. These two genera, Gryllus and Acheta, are so nearly identical that they are distinguished solely by differences in the male genitalia (Chopard, 1961). The present paper constitutes a survey of muscle activity patterns producing stridulation in four species of field crickets.
    [Show full text]
  • Chamber Music: an Unusual Helmholtz Resonator for Song Amplification in a Neotropical Bush-Cricket (Orthoptera, Tettigoniidae) Thorin Jonsson1,*, Benedict D
    © 2017. Published by The Company of Biologists Ltd | Journal of Experimental Biology (2017) 220, 2900-2907 doi:10.1242/jeb.160234 RESEARCH ARTICLE Chamber music: an unusual Helmholtz resonator for song amplification in a Neotropical bush-cricket (Orthoptera, Tettigoniidae) Thorin Jonsson1,*, Benedict D. Chivers1, Kate Robson Brown2, Fabio A. Sarria-S1, Matthew Walker1 and Fernando Montealegre-Z1,* ABSTRACT often a morphological challenge owing to the power and size of their Animals use sound for communication, with high-amplitude signals sound production mechanisms (Bennet-Clark, 1998; Prestwich, being selected for attracting mates or deterring rivals. High 1994). Many animals therefore produce sounds by coupling the amplitudes are attained by employing primary resonators in sound- initial sound-producing structures to mechanical resonators that producing structures to amplify the signal (e.g. avian syrinx). Some increase the amplitude of the generated sound at and around their species actively exploit acoustic properties of natural structures to resonant frequencies (Fletcher, 2007). This also serves to increase enhance signal transmission by using these as secondary resonators the sound radiating area, which increases impedance matching (e.g. tree-hole frogs). Male bush-crickets produce sound by tegminal between the structure and the surrounding medium (Bennet-Clark, stridulation and often use specialised wing areas as primary 2001). Common examples of these kinds of primary resonators are resonators. Interestingly, Acanthacara acuta, a Neotropical bush- the avian syrinx (Fletcher and Tarnopolsky, 1999) or the cicada cricket, exhibits an unusual pronotal inflation, forming a chamber tymbal (Bennet-Clark, 1999). In addition to primary resonators, covering the wings. It has been suggested that such pronotal some animals have developed morphological or behavioural chambers enhance amplitude and tuning of the signal by adaptations that act as secondary resonators, further amplifying constituting a (secondary) Helmholtz resonator.
    [Show full text]
  • Pinyon Engraver Beetle Acoustics: Stridulation Apparatus, Sound Production and Behavioral Response to Vibroacoustic Treatments in Logs
    insects Article Pinyon Engraver Beetle Acoustics: Stridulation Apparatus, Sound Production and Behavioral Response to Vibroacoustic Treatments in Logs Ivan Lukic 1 , Carol L. Bedoya 2, Evan M. Hofstetter 3 and Richard W. Hofstetter 1,* 1 School of Forestry, Northern Arizona University, Flagstaff, AZ 86011, USA; [email protected] 2 School of Biological Sciences, University of Canterbury, Christchurch 8140, New Zealand; [email protected] 3 BASIS, High School, Flagstaff, AZ 86001, USA; [email protected] * Correspondence: [email protected] Simple Summary: Acoustic technology is a potential tool to protect wood materials and live trees from colonization by bark beetles and other wood-infesting insects. Bark beetles such as the pinyon engraver beetle Ips confusus use chemical and acoustic cues to communicate and to locate potential mates in trees. In this study, we describe the structures and airborne sounds produced by the pinyon engraver beetle, and test the efficacy of vibroacoustic treatments for tree protection against this beetle. Only female beetles possessed sound producing structures, located on the back of the head and inside the thorax. We analyzed and described the airborne sounds, called chirps, produced by females when held by tweezers or placed on their back. We tested a wide variety of vibroacoustic treatments Citation: Lukic, I.; Bedoya, C.L.; played into logs but these sound treatments did not prevent male entry into logs and did not disrupt Hofstetter, E.M.; Hofstetter, R.W. female–male interactions, female tunneling behavior, reproduction or egg laying. We suggest further Pinyon Engraver Beetle Acoustics: studies if acoustic methods are to be utilized to control this bark beetle.
    [Show full text]
  • Sound Production and Associated Behavior in Insects1
    SOUND PRODUCTION AND ASSOCIATED BEHAVIOR IN INSECTS1 RICHARD D. ALEXANDER Department of Zoology and Entomology, The Ohio State University, Columbus 10 The number and variety of insects which produce sounds with specialized apparatus undoubtedly exceed those of all other living organisms combined, but only a few of these, the crickets, katydids, grasshoppers, and cicadas, make noises loud enough to be noticeable to man. These are the so-called singing insects, and their ancestors may well have been the first organisms on earth to communicate through sound waves transmitted in air. Although often obscured today by the intense and endless noises of civilization, insect sounds must have been among the loudest and most persistent sounds heard by primitive man. Their effect is apparent in art, mythology, and literature, and it may be more than mere coincidence that the chant, often called the most ancient of human music, bears a striking resemblance to the tuneless and repeti- tious insect song. Scientific interest in insect sounds dates at least to Aristotle, who over two thousand years ago separated two groups of Homoptera on the basis of whether or not they could produce sounds (Myers, 1929, p. 81). Today a complete bib- liography on sound production and perception in insects would contain several thousand references. Until recently, studies of insect sounds had to be based on human auditory impressions. For this reason, the variety and complexity of structure in insect sounds, chiefly involving pulsations delivered too rapidly for the human ear to perceive, are only beginning to be realized. Magnetic tape recorders and elec- tronic sound analyzing devices now provide objective means of analyzing and comparing these intricacies of structure, and have been responsible for a surge of interest in insect sounds in many different parts of the world (Busnel, 1954; Pringle, 1956).
    [Show full text]
  • Stridulation by Jadera Haematoloma (Hemiptera: Rhopalidae): Production Mechanism and Associated Behaviors
    BEHAVIOR Stridulation by Jadera haematoloma (Hemiptera: Rhopalidae): Production Mechanism and Associated Behaviors 1 2,3 1 2 ARIEL F. ZYCH, R. W. MANKIN, JAMES F. GILLOOLY, AND EVERETT FOREMAN Ann. Entomol. Soc. Am. 105(1): 118Ð127 (2012); DOI: http://dx.doi.org/10.1603/AN11048 ABSTRACT The Hemiptera displays a notable diversity of vibratory communication signals across its various families. Here we describe the substrate and airborne vibrations (sounds), the mechanism of production, and associated behaviors of Jadera haematoloma Herrich-Schaeffer, a member of the family Rhopalidae. Adult males and females both produce short, stereotyped sound bursts by anteriorÐ posterior movement of abdominal tergites I and II against a stridulitrum located on the ventral surface of the metathoracic wing. Sound bursts are produced by a single adult male or female when physically touched by another adult, and are strongly associated with being crawled on by the approaching individual, but are not produced in response to contact with other arthropods or when pinched with forceps. The propensity to produce sounds when crawled upon decreases during the mating season. These sound bursts by J. haematoloma likely are communication signals. Rhopalidae has been signiÞcantly absent from the vibratory communication literature until now. Although the sounds are produced using a mechanism common to vibratory communication systems in closely related Het- eropteran Hemiptera, the sounds in these other species function primarily in courtship or in motherÐ daughter interactions, which suggests that the functions of stridulation and the behavioral contexts have diversiÞed in the Heteroptera. KEY WORDS insect communication, mating, stridulation, Heteroptera Acoustic and vibratory communication is incredibly Rhopalidae (Hemiptera: Heteroptera), Jadera haema- diverse and has arisen multiple times during the evo- toloma Herrich-Schaefer, and describe for the Þrst lution of Hemiptera.
    [Show full text]
  • Resonators in Insect Sound Production: How Insects Produce Loud Pure-Tone Songs
    The Journal of Experimental Biology 202, 3347–3357 (1999) 3347 Printed in Great Britain © The Company of Biologists Limited 1999 JEB2136 RESONATORS IN INSECT SOUND PRODUCTION: HOW INSECTS PRODUCE LOUD PURE-TONE SONGS H. C. BENNET-CLARK* Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK *e-mail: [email protected] Accepted 15 June; published on WWW 16 November 1999 Summary In a resonant vibration, two reactive elements, such as a produced by the excitation of a simple resonator, the song mass and a spring, interact: the resonant frequency frequency may not be constant, suggesting that other depends on the magnitude of these two elements. The build- factors, such as the mechanism of excitation, or variation up and decay of the vibration depend on the way the of the effective mass or elasticity of the system during resonator is driven and on the damping in the system. sound production, may be additional determinants of the The evidence for the existence of resonators in insect song frequency. sound production is assessed. The mechanics of different Loud, and hence efficient, transduction of the energy of types of sound-producing system found in insects is a mechanical resonator into sound may involve a second described. Mechanical frequency-multiplier mechanisms, stage of transduction which, by damping the resonator, which convert the relatively slow contraction of muscles to may compromise tonal purity. Some insect singers resolve the higher frequency of the sound, are commonly used to this problem by tuning both stages of transduction to the convert the comparatively slow muscle contraction rate to same frequency, thereby maintaining tonal purity.
    [Show full text]
  • Goliath Bird-Eating Tarantula Class: Arachnida
    Theraphosa blondi Goliath Bird-Eating Tarantula Class: Arachnida. Order: Araneae. Family: Therasphosidae. Other names: Giant Bird-eating spider, Giant Tarantula, Goliath Birdeater Physical Description: This Amazonian spider is the second largest spider in the world, second only to the giant huntsman spider. It has a leg span of 12 inches across, about the size of a small dinner plate and weigh up to 6oz making it the largest spider by mass. Like all tarantulas, it is a very hairy spider and the hairs are actually hollow bristles that are produced as part of their exoskeleton. Their bodies are made up of two external parts; the cephalothorax (fused head and thorax, where legs attach) and their abdomen. They have weak eyesight, their eight eyes only seeing differences in the level of light. Diet in the Wild: Insects, frogs, small snakes, lizards, rodents, bats, and (although rarely) young birds. Diet at the Zoo: Mice and crickets Habitat & Range: Northern South America in swamps/marshy areas deep within the primary rainforest. Life Span: For females, 15-25 years. The males will only live one year or less after mating. Perils in the wild: Predators include spider wasps, some snakes, and other tarantulas. Smaller insects can take advantage of a freshly molted tarantula. Physical Adaptations: With their inch long fangs, the tarantula will inject venom that works on the nervous system which paralyzes its smaller victims. They then regurgitate digestive juices secreted from openings in the chelicerae onto their victims that break down soft tissue. The spider is then able to suck up its prey.
    [Show full text]
  • Sound Modulation in Katydids
    Sound Modulation in Singing Katydids Using Ionic Polymer- Metal Composites (IPMCs) Yan Zhou 1, Cheng-Wei Chiu 2, Carlos J. Sanchez 2, Jorge M. González 3,4 , Benjamin Epstein 5, 5 3 1,2 David Rhodes , S. Bradleigh Vinson , Hong Liang Abstract: Many insect families have evolved to produce and detect complex singing patterns for the purposes of mating, display of dominance, predator escape, and other needs. While the mechanisms of sound production by insects have been thoroughly studied, man-machine exploitation of such mechanisms has remained unreported. We therefore describe a method to modulate the frequency spectrum in the chirp call of a singing insect, Gampsocleis gratiosa (Orthoptera: Tettigoniidae), a large katydid indigenous to China and commonly known as Guo Guo or Chinese Bush Cricket. The chirp modulation was achieved through the contact of a ribbon of Ionic Polymer-Metal Composite (IPMC) against wing of the insect. The IPMC effectively served as an actuator when a small DC voltage was applied to the ribbon’s faces. By applying a sequential on/off voltage waveform to the IPMC ribbon, the katydid’s chirp was modulated in a corresponding manner. This configuration can be used as part of a broader application of using singing insects to harness their acoustic power to produce and propagate machine-induced messages into the acoustic environment. Keywords: chirp modulation, katydid, IPMC [11–13] stroke of a closing pair of wings . 1 Introduction The above stridulation mechanism applies to the Insects belonging to the families Gryllidae (crickets, katydid Gampsocleis gratiosa , the model insect of this “true crickets”) and Tettigoniidae (katydids, bush reported effort.
    [Show full text]