Enhanced fitness due to higher fecundity,increased defence against a specialist and tolerance towards a generalist herbivore in an invasive annual plant  

作　　者：D.Abhilasha J.Joshi 

机构地区：[1]Institute of Environmental Sciences,University of Zurich,Winterthurerstrasse 190,CH-8057 Zurich,Switzerland [2]Institute of Biochemistry and Biology,Biodiversity Research/Botany,University of Potsdam,Maulbeerallee 1,14469 Potsdam,Germany

出　　处：《Journal of Plant Ecology》2009年第2期77-86,共10页植物生态学报（英文版）

基　　金：This work was supported by a grant from the Swiss National Science Foundation to J.J.(nr.3100AO-104006).

摘　　要：Aims The superior performance of many non-indigenous species in a new range can be attributed to different factors such as pre-adaptation to environmental conditions in new areas or to factors inherent to displacement mechanisms such as loss of co-evolved pathogens and herbivores that increase the speed of evolutionary change towards a shift in allocation from defence to growth and reproduction.To assess the importance of the different mechanisms governing the success of Conyza canadensis,a globally successful invader,we simultaneously tested several recent hypotheses potentially explaining the factors leading to biological invasion.Methods We tested(i)whether plants from the non-native range showed a higher fitness than plants from the native North American range,(ii)whether they differed in resistance against an invasive generalist herbivore,the slug Arion lusitanicus and against a recently established specialist aphid herbivore,Uroleucon erigeronense and(iii)experimentally assessed whether C.canadensis releases allelopathic chemicals that have harmful effects on competing species in the nonnative range.We compared populations along a similar latitudinal gradient both in the native North American and invasive European range and analysed patterns of adaptive clinal variation in biomass production.Important Findings The invasion success of C.canadensis in Europe cannot be attributed to a single trait,but to a combination of factors.Invasive plants benefited from increased growth and above all,increased reproduction(a key trait in an annual plant)and were less attacked by a co-migrated specialist enemy.The observed loss of defence against generalist slugs did not translate into a decreased fitness as invasive C.canadensis plants showed a high re-growth potential.In contrast to earlier in vitro studies,we detected no allelopathic effects on the competing flora in the non-native range.The latitudinal cline in vegetative biomass production in the non-native range observed in our common garden study indicates a high a

关 键 词：ALLELOPATHY biological invasions Conyza canadensis EICA hypothesis generalist/specialist herbivory latitudinal clines biogeographic comparison common garden 

分 类 号：R73[医药卫生—肿瘤]