butterfly-蝴蝶-教學(xué)講解課件

Butterfly1Butterflyisaninsectoftheorder

Lepidoptera.Unlikemanyinsects,butterfliesdonot

experienceanymphperiod,butinsteadgothroughapupal(蛹的）stagewhichliesbetweenthelarva（幼蟲）andtheadultstage(theimago成蟲).Butterfliesaretermedasholometabolous（完全變態(tài)）insects,andgothroughcompletemetamorphosis(變態(tài)）.2Thefour-stagelifecycle1.Egg2.Larva,knownasacaterpillar

3.Pupa(chrysalis)4.Adultbutterfly(imago)3Egg4Butterflyeggsconsistofahard-ridgedouterlayerofshell,calledthechorion(絨毛膜）.Thisislinedwithathincoatingofwax（蠟）whichpreventstheeggfromdryingoutbeforethelarvahashadtimetofullydevelop.Eacheggcontainsanumberoftinyfunnel-shapedopeningsatoneend,calledmicropyles（卵孔）（toallowsperm（精子）toenterandfertilizetheegg）.Butterflyeggsarefixedtoaleafwithaspecialgluewhichhardensrapidlyandwilldeformtheshapeoftheegg.5Eggsareusuallylaidonplants.Eachspeciesofbutterflyhasitsownhostplantrangeandwhilesomespeciesofbutterflyarerestrictedtojustonespeciesofplant.6Theeggstagelastsafewweeksinmostbutterfliesbuteggslaidclosetowinter,especiallyintemperateregions,gothroughadiapause(滯育）stage,andthehatching（孵卵）maytakeplaceonlyinspring.Otherbutterfliesmaylaytheireggsinthespringandhavethemhatchinthesummer（northernspecies）.7Caterpillars8Butterflylarvae,orcaterpillars,consumeplant

leavesandspendpracticallyalloftheirtimeinsearchoffood.Althoughmostcaterpillarsareherbivorous(planteating),afewspeciesareentomophagous(insecteating).9Butterflycaterpillarshavethreepairsoftruelegsfromthethoracic(胸）segmentsandupto6pairsofprolegsarisingfromtheabdominal（腹部）segments.10wingdevelopment11Wingsorwingpads（翅芽）arenotvisibleontheoutsideofthelarva,butwhenlarvaearedissected(切開）,tinydevelopingwingdiskscanbefoundonthesecondandthirdthoracicsegments,inplaceofthespiracles(呼吸孔）thatareapparentonabdominalsegments.Wingdisksareverysmalluntilthelastlarvalinstar.12Pupa蝶蛹1314Thelarvatransformsintoapupa(orchrysalis蛹)byanchoring（依靠）itselftoasubstrate（基質(zhì)）andmoulting（換毛）forthelasttime.Thechrysalisisusuallyincapableofmovement.Thepupaltransformationintoabutterflythroughmetamorphosis（變態(tài)）hasheldgreatappealtomankind.Totransformfromtheminiaturewingsvisibleontheoutsideofthepupaintolargestructuresusableforflight,thepupalwingsundergorapidmitosis（有絲分裂）andabsorbagreatdealofnutrients.15AdultorImago16Theadultissexuallymature.AsLepidoptera,butterflieshavefourwingsthatarecoveredwithtinyscales.Theforeandhindwingsarenothookedtogether,permittingamoregracefulflight.Anadultbutterflyhassixlegs,butinthenymphalids,thefirstpairisreduced.Afteritemergesfromitspupalstage,abutterflycannotflyuntilthewingsareunfolded.Anewly-emergedbutterflyneedstospendsometimeinflatingitswingswithbloodandlettingthemdry,duringwhichtimeitisextremelyvulnerabletopredators.17habitButterfliesfeedprimarilyonnectar(花蜜）fromflowers.Somealsoderivenourishmentfrompollen（花粉），treesap（汁）,rottingfruit,dung（家畜糞便）,anddissolvedmineralsinwetsandordirt.Butterfliesareimportantaspollinators（傳粉媒介）18Asadults,butterfliesconsumeonlyliquidsandthesearesuckedbymeansoftheirproboscis（喙）.Theyfeedonnectarfromflowersandalsosipwaterfromdamppatches.Thistheydoforwater,forenergyfromsugarsinnectarandforsodium（鈉）andothermineralswhicharevitalfortheirreproduction.Severalspeciesofbutterfliesneedmoresodiumthanprovidedbynectar.Theyareattractedtosodiuminsaltandtheysometimeslandonpeople,attractedbyhumansweat.Besidesdamppatches,somebutterfliesalsovisitdung,rottingfruitorc