简介：Inthenaturalworld,plantsandanimalshaveevolvedovertimetobestadapttotheenvironment.Theyinteractveryeffectivelywiththesurroundingenvironmentbyexchangingenergiesandmassflowacrosstheircuticlesofspecificmicrostructuresandfunctionstoachieveperfectenergybalance.Suchdifferentfunctionsmayincludethelimitationofuncontrolledlossofwater,protectionfromsolarradiation,microeffectofinducedturbulenceonflowdragreduction,defenceagainstpathogens,changingsurfacewettabilityandhydropho-

简介：QuestionsconcerningthefunctionalroleofthehollowregionofthebutterflyPyrameisatalanta(L.)scaleareexperimentallyinvestigated.Attentionwasinitiallydirectedtothisproblembyobservationofthecomplexmicrostructureofthebutterflyscaleaswellasotherstudiesindicatinghigherliftonbutterflywingscoveredwithscale.Theaerodynamicforcesweremeasuredfortwooscillatingscalemodels.ResultsindicatedthattheaircavityofanoscillatingmodelofthePyrameisatalanta(L.)scaleincreasedtheliftbyafactorof1.15andreducedthedampingcoefficientsbyafactorof1.38.Themodificationoftheaerodynamiceffectsonthemodelofbutterflyscalewasduetoanincreaseofthevirtualairmass,whichinfluencedthebody.Thehollowregionofthescaleincreasedthevirtualairmassbyafactorof1.2.Thevirtualmassofthebutterflyscalewiththehollowregionwasrepresentedasthesumofairmassoftwoimaginarygeometricalfigures:acircularcylinderaroundthescaleandaright-angledparallelepipedwithinthehollowregion.TheinteractionmechanismofthebutterflyPyrameisatalanta(L.)scalewithaflowwasdescribed.Thisnovelinteractionmechanismexplainedmostgeometricalfeaturesoftheairpermeablebutterflyscale(invertedV-profileoftheridges,nozzleofthetipedge,hollowregion,andopeningsoftheupperlamina)andtheirarrangement.

简介：Waterstridersareinsectslivingonthewatersurface,overwhichtheycanmoveveryquicklyandrarelygetwetted.Wemeasuredtheforceoffreewalkinginwaterstriders,usingahairattachedtotheirbacksanda3Dstraingauge.Theerrorwascalculatedbycomparingforceanddataderivedfromgeometryandwasestimatedas13%.Femalesonaveragewerestronger(1.32mN)thanmales(0.87mN),however,theratioofforcetoweightwasnotsignificantlydifferent.Comparedwithotherlighterspecies,Aquariuspaludumseemsstronger,buttheratioofforcetoweightisactuallylower.A.paludumappliesabout0.3mN·cm-1to0.4mN·cm-1withitsmid-legs,thusavoidingpenetratingthesurfacetensionlayerwhilepropellingitselfrapidlyoverthewatersurface.WealsoinvestigatedtheexternalmorphologywithSEM.Thebodyiscoveredbyeffectivelytwolayersofmacro-andmicro-hairs,whichrendersthemhydrophobic.Thesetaearelong(40μm-60μm)andstiff,beingresponsibleforwaterproofing,andthemicrotrichiaaremuchsmaller(<10μm),slender,andflexible,holdingabubbleoverthebodywhensubmerged.