简介：

简介：

简介：Background:Manytreespeciesintropicalforestshavedistributionstrackinglocalridge-slope-valleytopography.Previousworkina50-haplotinKorupNationalPark,Cameroon,demonstratedthat272species,or63%ofthosetested,weresignificantlyassociatedwithtopography.Methods:Weusedtwocensusesof329,000trees≥1cmdbhtoexaminedemographicvariationatthissitethatwouldaccountforthoseobservedhabitatpreferences.Wetestedtwopredictions.First,withinagiventopographichabitat,speciesspecializingonthathabitat(‘residents')shouldoutperformspeciesthatarespecialistsofotherhabitats(‘foreigners').Second,acrossdifferenttopographichabitats,speciesshouldperformbestinthehabitatonwhichtheyspecialize(‘home')comparedtootherhabitats(‘away').Species'performancewasestimatedusinggrowthandmortalityrates.Results:Inhierarchicalmodelswithspeciesidentityasarandomeffect,wefoundnoevidenceofademographicadvantagetoresidentspecies.Indeed,growthratesweremostoftenhigherforforeignspecies.Similarly,comparisonsofspeciesontheirhomevs.awayhabitatsrevealednosignofaperformanceadvantageonthehomehabitat.Conclusions:Werejectthehypothesisthatspeciesdistributionsalongaridge-valleycatenaatKoruparecausedbyspeciesdifferencesintrees≥1cmdbh.Sincetheremustbeademographiccauseforhabitatspecialization,weofferthreealternatives.First,thedemographicadvantagespecialistshaveathomeoccursatthereproductiveorseedlingstage,insizessmallerthanwecensusintheforestplot.Second,speciesmayhavehigherperformanceontheirpreferredhabitatwhendensityislow,butwhenpopulationbuildsup,therearenegativedensity-dependentfeedbacksthatreduceperformance.Third,demographicfilteringmaybeproducedbyextremeenvironmentalconditionsthatwedidnotobserveduringthecensusinterval.

简介：Sitobionavenae(F.)是能在Poaceae在各种各样的植物上幸存的世界范围的一个重要谷物害虫，但是不同主人植物上的分叉的选择应该支持专业化遗传型或主人赛跑的进化。为了评估他们的资源，使用策略，S的克隆。avenae从燕麦和大麦被收集。为这些克隆的主人转移实验在实验室被进行比较他们的健康特点。我们的结果证明大麦克隆有显著地更低的肥沃并且趋于有从大麦转移到燕麦的更长发展的时间。然而，在他们被转移到大麦以后，燕麦克隆更快发展了。从燕麦和大麦的克隆以肥沃和美女的发展时间分叉到某个程度。大麦克隆的分离和S的燕麦克隆。avenae在主要部件分析也是明显的。大麦克隆趋于比燕麦克隆为健康特点有更高宽广感觉的可遗传性，显示在他们之间的区别的基因基础。大麦克隆从专门化的二项措施与燕麦克隆相比显示出专门化的显著地更高的程度(即，Xsp和Ysp)。因此，大麦克隆被专业化到某个程度，但是燕麦克隆看起来被概括。S的健康。avenae克隆趋于与专门化的更高的程度增加。向在S的生态的专门化的进化。avenae克隆，以及内在的基因基础，被讨论。