As il is used in line ?0, Ihe word rise,¥ m05t nearly means". ascends. soars. maierialize). GO ON TO THE NEXT PAGE. Passage IV as ihE individual Tibs bucklc. This series of click.s meroes lo form a (rain of vibraiions ai Ihe cicada's sono 55 frequellcy. NATURAL SCIENCE: This passage is aclapled from the article -How Cic2das Make Their Noise. by Henry C. 8ennet-Clark {Q1998 by Scientific American, Inc.). A click.from the rib of. a tymbal produces hioh sound pressures Wiihin the cicada's abdonen. In mosi species of cicada, this region is filled 12r(yel) by an air sac. The abdoTnen conEains a pair of ihin eardiums that 60 exlend Ihe full widih of Ihe N'cniral surface and serve as acousric window's, connecting Ihe air sac to ihe outside 'orld. The early dusk" of late spriry(r can be quili a noisy lirne. EN'cry year some of ihe Sv)veral Ihousand species of cicada emeroe from underoround, and Ihe males becrin ID sin(r Iheir raucous. aimosl deafening. song. 5 Arnon(r Ihe5e virtuosos of ihe insect rcalm, the males of one species of Ausiralian cicada are disiinouished for haN'ino the loudesl insecl call measured so far. .The hivh-pressure sound pulses produced by the tymbals and ribs create a sympathetic resonance in the -65 abdominal air sac. Because Ihe eardrums are laroer ihan Ihe tvtnbals. they seri"e as an effeciii'e means of radial- ino the sound bel'ond the body-causino it to be about ?0 times louder Ihan if ihe sound were to emanate simply from the liny iymbals. Thus, Ihe inseci mana£es 70 10 broadcasi oi'er a far greater range. Cicadas are plant-suckino buos. related most closelv to aphids and leafhopper>. They are laroe-and 10 nois). for in%ecis Ihat feast on sap: the sniallesi 2re l O millimelers (iUs1 under half an inch) long, Ihe largesi 100 millimeiers (four inchcs). Female cicadas lay their eoos in the stems nf plants or in trees. Later, Ihe newly hatched youno drop to Ihe oround and burrow in search 15 of planl rools 10 lap. They remain underground Ihrough- out Iheir larN'al life. iihich can lasi rn2ny )'ears-, the l J- and 17-)'ear life ci'cles of ihe American periodic cicadas are amoncr Ihe lontyesl. lk.hen ihe larvae emerge. they molc inEO ii'inged adulis and Ihen 131'e for only a 20 few, .eeks. Durino this lime, Ihe males sintr to attract males. Alib.ouoh sound is radiated via the eardrums, Ihe sensor), pari of Ihe m4le ear is in a separaie capsule, connecied 10 ihe eardrum by way. of a" stnall canal. Thls separation niay protect the males, prevenlino Ihcm from 75 voin? deaf. The abdomen and eardiums do rtiore, Ihouoh, than simply Ihrow the 50U_4d into Ihc world. They serTr"e to rnainiain ihe quality of the all-impor12nl rnaiino sono B}, exiendino ihe abdomen and b! openin£ Ihe opercuia 80 ihat coi'er rhe ejrdrurns. Ihe cicada can tune Ihe abdotn- inal.rtsonator io Ib,e t"requency.of the sound pulses pro- .duced'..by.the'iymbals.' The abdominal.structures'.can' therefore increase Ihe puriiy or Ihe loudness of.lhe son(r They aci as ,ha1 is called in musical teitTrinolocr that is. the 85 a resonant acoustic load 10 thc t)'mbals correct and balance Ihe sound Sy51em. Why Ihe insecis, calling sorig is so loud 15 noi entirely ulldersiood. One possibilily is IhaL the sound may saluraie Ihe ears of predators. makino ji hard io 25 locale Ihe cicada precisely. Or il mav be thal laroer, cicadas hai'e a 12ruer hotne rane and need io call louder io atiiaci 3 niaTe. do k-noiv ihat the females are not hard of hcarino: they hear just fLne M'ith Ihresh- olds of 30 to 40 decibels. And il is quile likely ihai 30 female cicada£ can discriminate beiiveen males on the basis of sontr quanlilj. and qualit%'. just as female crick- ets do. similar mechanism seetns to occur in many other species of cicada, and related sound-production systems haN'e been described in oiher loud insects as ell. Yei to Ihe best of our knowledoe, Ihe males of this Australian cicada species retnain Ihe noisiesl insecis around. The key 10 undersiandin(T how Ihe male5 tnake Iheir po,erful noise lies in isolaiino Ihe different 35 aspecis ol Ihe sound-production mechanism. The pri- mary equiprnent is a pair of domed iymbals: or drum- like siruciures, Ihai SIL on eiiher side of Ehe abdomen. Each of Lhese elasiic, resonant OFfjaTrs has a row of four corkk'ex ribs Ihai runs lonc7itudinall5 up and dow'n its 40 surface. These ribs are fIexibly connected to one anoiher as KK ell as 10 a lariye oval plai¢ dl IE1¢ rear of Ilie t)mb21. Aiiached to each oi'al t)'mbJl plaie, in turn: is a lar<Te, fast muscle. The conlraciion of Ihese muscles 45 disiorls Ihe domed iwtnbals, creaiiniF a pulse of sound. Becau'se Ihei, coniraci so rapidly. Ihe muscles pro- duce knnouoh eneroy in Ihe first Ihree milliseconds of each contraciion 10 cause tu'o or ihree of Ihe curl'ed ribs on each riirtibal 10 buck-le in sequence. This moiion 50 causes iu'o or Ihree Slep,ISe inil'ard moi'etnenls of the oval plate. The siored elaslic enei released durIng Ihese stepi¥'ise moi'einenis produces a brief. loud cl;cL
