38 - Night of the Living Ants (B级)

NightoftheLivingAnts(B级)Whenanantdies,otherantsmovethedeadinsectoutofthenest.Sometimes,thedeadantgetsmovedawayverysoon—withinanhourofdying.Thisbehaviorisinterestingtoscientists,whowonderhowantsknowforsure—andsosoon—thatanotherantisdead.Onescientistrecentlycameupwithawaytoexplainthisantbehavior.Dong-HwanChoeisabiologist,ascientistwhostudieslivingthings,attheUniversityofCalifornia,Riverside.ChoefoundthatArgentineantshaveachemicalontheoutsideoftheirbodiesthatsignalstootherants,“I’mdead—takemeaway.”Butthere’satwisttoChoe’sdiscovery.Theseantsarealittlebitlikezombies.Choesaysthatthelivingants—notjustthedeadones—havethisdeathchemical.Inotherwords,whileanantcrawlsaround,perhapsinapicnicorhome,it’stellingotherantsthatit’sdead.Whatkeepsantsfromhaulingawaythelivingdead?Choehasananswerforthatquestion,too.HefoundthatArgentineantshavetwoadditionalchemicalsontheirbodies,andthesetellnearbyantssomethinglike,“Wait—I’mnotdeadyet.”SoChoe’sresearchturneduptwosetsofchemicalsignalsinants:onesays,“I’mdead,”theothersetsays,“I’mnotdeadyet.”Otherscientistshavetriedtofigureouthowantsknowwhenanotherantisdead.Ifanantisknockedunconscious,forexample,otherantsleaveitaloneuntilitwakesup.Thatmeansantsknowthatunmovingantscanstillbealive.Manyscientists,likeChoe,thinktheremustbeachemicalonadeadant’sbody.ChoesuspectsthatwhenanArgentineantdies,thechemicalthatsays“Wait—I’mnotdeadyet”quicklygoesaway.Oncethatchemicalisgone,onlytheonethatsays“I’mdead”isleft.Whenotherantsdetectthe“dead”chemicalwithoutthe“notdeadyet”chemical,theyhaulawaythebody.Thisidea—thatsomechemicalsfadeaway—wasChoe’shypothesis,orideatotest,forhisexperiment.Totesthishypothesis,ChoeandhisteamputdifferentchemicalsonArgentineantpupae.Apupaisthestageofanant’slifejustbeforeitbecomesanadult.Whenthescientistsusedthe“I’mdead”chemical,otherantsquicklyhauledthetreatedpupaeaway.Whenthescientistsusedthe“Wait—I’mnotdeadyet”chemicals,otherantsleftthetreatedpupaealone.Choebelievesthisbehaviorshowsthatthe“notdeadyet”chemicalsoverridethe“dead”chemicalwhenpickedupbyadultants.Andthatwhenanantdies,the“notdeadyet”chemicalsfadeaway.Othernearbyantsthendetecttheremaining“dead”chemicalandremovethebodyfromthenest.UnderstandingthisbehaviormayhelpscientistsfigureouthowtostopArgentineantsfrominvadingnewplacesandcausingproblems.ChoewouldliketofindawaytousethenewlydiscoveredchemicalstospreadantkillertoArgentineantnests.Theants’removalbehaviorisimportanttotheoverallhealthofthenest.Theirbehaviorisnotsodifferentfromours:Whenahumandies,thebodyisusuallyburiedorcrematedwithinafewdays.“Beingabletoquicklyremovedeadindividualsandotherpossiblesourcesof[disease]…isextremelyimportantforallanimalslivinginsocieties,includingus,”saysPatriziad’EttorreoftheUniversityofCopenhagen.“Thinkaboutalltheeffortandmoneythatweinvestdailyinwastemanagement.”第三十八篇NightoftheLivingAnts(B级)Whenanantdies,otherantsmovethedeadinsectoutofthenest.Thisbehaviorisinterestingtoscientists,whowonderhowantsknowforsure—andsosoon—thatanotherantisdead.Dong-HwanChoe,ascientistattheUniversityofCaliforniafoundthatArgentineantshaveachemicalontheoutsideoftheirbodiesthatsignalstootherants,“I’mdead—takemeaway.”Butthere’satwisttoChoe’sdiscovery.Theseantsarealittlebitlikezombies.Choesaysthatthelivingants—notjustthedeadones--havethisdeathchemicalInotherwords,whileanantcrawlsaround,perhapsinapicnicorhome,it’stellingotherantsthatit’sdeads.Whatkeepsantsfromhaulingawaythelivingdead?ChoefoundthatArgentineantshavetwoadditionalchemicalsontheirbodies,andthesetellnearbyantssomethinglike,“Wait—I’mnotdeadyet.”SoChoe’sresearchturneduptwosetsofchemical.signalsinants:onesays,“I’mdead,”theothersetsays,“I’mnotdeadyet.”Otherscientistshavetriedtofigureouthowantsknowwhenanotherantisdead.Ifanantisknockedunconscious,otherantsleaveitaloneuntilitwakesup.Thatmeansantsknowthatunmovingantscanstillbealive.ChoesuspectsthatwhenanArgentineantdies,thechemicalthatsays“Wait-I’mnotdeadyet”quicklygoesaway.Oncethatchemicalis,gone,onlytheonethatsays“I’mdead”isleft.“It’sbecausethedeadantnolongersmellslikealivingantthatitgetscarriedtothegraveyard,notbecauseitsbodyreleasesnewuniquechemicalsafterdeath,”saidChoe.Whenotherantsdetectthe“dead”chemicalwithoutthe“notdeadyet”chemical,theyhaulawaythebody.ThiswasChoe’shypothesis.Totesthishypothesis,ChoeandhisteamputdifferentchemicalsonArgentineantpupae.Whenthescientistsusedthe“I’mdead”chemical,otherantsquicklyhauledthetreatedpupaeaway.Whenthescientistsusedthe“Wait—I’mnotdeadyet”chemicals,otherantsleftthetreatedpupaealone.Choebelievesthisbehavior,showsthatthe“notdeadyet”chemicalsoverridethe“dead”chemicalwhenpickedupbyadultants.Andthatwhenanantdies,the“notdeadyet”chemicalsfadeaway.Othernearbyantsthendetecttheremaining“dead”chemicalandremovethebodyfromthenest.练习：1.Whatismeantby“deathchemical”mentionedinparagraph3?AAchemicalthatcontainspoisonBAchemicalthatcausesdeath.CAchemicalthatannouncesdeath.DAchemicalthatpreventsdeath.2.Whichofthefollowingisclosestinmeaningtothequestion“Whatkeepsantsfromhaulingawaythelivingdead?(paragraph4)”?AHowdoantsknowwhatistobehauledawayfromthede