新sat官方指南阅读第十五篇全解析

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1、官网网站：imzsat.genshuixue.com________________________________________________________________新SAT官方指南阅读第十五篇全解析ThispassageisadaptedfromRichardJ.SharpeandLisaHeyden,“HoneyBeeColonyCollapseDisorderisPossiblyCausedbyaDietaryPyrethrumDeficiency.”©2009byElsevierLtd.Colonycollapsediso

2、rderischaracterizedbythedisappearanceofadultworkerbeesfromhives.HoneybeesarehoststothepathogeniclargeectoparasiticmiteVarroadestructor(Varroamites).Thesemitesfeedonbeehemolymph(blood)andcankillbeesdirectlyorbyincreasingtheirsusceptibilitytosecondaryinfectionwithfungi,bacteri

3、aorviruses.Littleisknownaboutthenaturaldefensesthatkeepthemiteinfectionsundercontrol.5PyrethrumsareagroupoffloweringplantswhichincludeChrysanthemumcoccineum,Chrysanthemumcinerariifolium,Chrysanthemummarschalli,andrelatedspecies.Theseplantsproducepotentinsecticideswithanti-mi

4、teactivity.Thenaturallyoccurringinsecticidesareknownaspyrethrums.Asynonymforthenaturallyoccurringpyrethrumsispyrethrinandsyntheticanaloguesofpyrethrumsareknownaspyrethroids.Infact,thehumanmiteinfestationknownas10scabies(Sarcoptesscabiei)istreatedwithatopicalpyrethrumcream.We

5、suspectthatthebeesofcommercialbeecolonieswhicharefedmono-cropsarenutritionallydeficient.Inparticular,wepostulatethattheproblemisadietdeficientinanti-mitetoxins:pyrethrums,andpossiblyothernutrientswhichareinherentinsuchplants.Without,atleast,intermittentfeedingonthepyrethrump

6、roducingplants,beecoloniesaresusceptibletomite15infestationswhichcanbecomefataleitherdirectlyorduetoasecondaryinfectionof1官网网站：imzsat.genshuixue.com________________________________________________________________immunocompromisedornutritionallydeficientbeesThissecondaryinfec

7、tioncanbeviral,bacterialorfungalandmaybeduetooneormorepathogens.Inaddition,immunocompromisedornutritionallydeficientbeesmaybefurtherweakenedwhencommerciallyproducedinsecticidesareintroducedintotheirhivesbybeekeepersinanefforttofightmiteinfestation.Wefurther20postulatethatthe

8、properdosagenecessarytopreventmiteinfestationmaybebetterlefttothebees,whoma