Some types of plant accumulate liquid in their inflorescences creating phytotelmata.These environments protect the flowers against florivory,although they may be colonized by aquatic or semiaquatic florivorous insect ...Some types of plant accumulate liquid in their inflorescences creating phytotelmata.These environments protect the flowers against florivory,although they may be colonized by aquatic or semiaquatic florivorous insect larvae,whose effects on the fitness of the plants remain unclear.We tested the hypothesis of floral antagonism by the occupants of phytotelmata,which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant,reducing its fecundity.We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata(Heliconiaceae)to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts.We found that the foraging of the hoverfly(Syrphidae)and moth(Lepidoptera)larvae in the inflorescences contributed to a decline in the fecundity of the plant.While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts,the syrphid only affected the fruiting bracts,which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly.By contrast,soldier fly(Stratiomyidae)had a neutral effect on fecundity,while foraging in flowering or fruiting bracts.These findings corroborate our hypothesis,that herbivory by the larval occupants represents cost to the host plant having phytotelmata.The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources,which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.展开更多
Aims Early models of plant defense conceived resistance and tolerance to herbivore damage as mutually exclusive strategies.support for this idea has been equivocal and studies on these two strategies are still needed ...Aims Early models of plant defense conceived resistance and tolerance to herbivore damage as mutually exclusive strategies.support for this idea has been equivocal and studies on these two strategies are still needed to understand the evolution of defenses in natural populations.In Arabidopsis lyrata,the production of trichomes,a documented resistance trait,has been associated with a fitness cost in the absence of herbivores.We examined whether trichome production is also associated with reduced tolerance to simulated herbivore damage.Methods We conducted a field experiment in a natural swedish population of A.lyrata where we inflicted leaf(0 vs.50%of the area of each leaf removed)and inflorescence damage(0 vs.50%of inflores-cences removed)to trichome-producing and glabrous plants in a factorial design.We examined the response(survival,growth and reproduction)of the plants to the imposed damage over 2 years.Important Findingstrichome-producing plants were not less tolerant than glabrous plants to simulated herbivore damage(no significant morph×leaf damage or morph×inflorescence damage interactions).Inflorescence and leaf damage had independent negative effects on the performance of damaged plants.leaf damage reduced rosette size the year of damage,but effects on reproductive output in the year of damage,and on survival and reproductive performance the following year were weak and not statistically significant.Inflorescence damage significantly reduced the number of flowers,fruits and seeds the year of damage,but not in the following year.Irrespective of morph,the study population was more tolerant to leaf than to inflorescence damage.the results indicated no trade-off between trichome production and tolerance,suggesting that these two defense mechanisms have the potential to evolve indepen-dently in this A.lyrata population.展开更多
基金Funding for this study was provided by the Brazilian Coordination for Higher Education Personnel Training(CAPES:Coordenacao de Aperfeic¸oamento de Pessoal de Nıvel Superior)for providing C.C.C.M.with a doctoral research scholarship(this study was financed in part by CAPES—Finance Code 001).The Rio de Janeiro State Research Foundation(FAPERJ:Fundacao Carlos Chagas Filho de Amparo aPesquisa do Estado do Rio de Janeiro)provided C.C.C.M.with a grant(DSC-10 process E_01/201.955/2017)supported the research of M.A.S.A.(CNE processes E-26/203191/2015,E-26/202.835/2018)The Brazilian National Research Council(CNPq:Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico)provided M.A.S.A.with a research fellowship(PQ processes 305798/2014-6,306.579/2018-9).
文摘Some types of plant accumulate liquid in their inflorescences creating phytotelmata.These environments protect the flowers against florivory,although they may be colonized by aquatic or semiaquatic florivorous insect larvae,whose effects on the fitness of the plants remain unclear.We tested the hypothesis of floral antagonism by the occupants of phytotelmata,which predicts that florivory by the occupants of the phytotelmata represents a cost to the female fitness of the plant,reducing its fecundity.We manipulated experimentally the infestation by 3 florivores larvae species occupants of phytotelmata in inflorescences of Heliconia spathocircinata(Heliconiaceae)to test for negative direct trophic effects on the fecundity of the flowering and fruiting bracts.We found that the foraging of the hoverfly(Syrphidae)and moth(Lepidoptera)larvae in the inflorescences contributed to a decline in the fecundity of the plant.While the lepidopteran impacted fecundity when foraging in both flowering and fruiting bracts,the syrphid only affected the fruiting bracts,which indicates that the nectar and floral tissue are the principal resource exploited by the hoverfly.By contrast,soldier fly(Stratiomyidae)had a neutral effect on fecundity,while foraging in flowering or fruiting bracts.These findings corroborate our hypothesis,that herbivory by the larval occupants represents cost to the host plant having phytotelmata.The negative influence of this foraging on plant fecundity will nevertheless depend on the consequences of the exploitation of resources,which vary considerably in ephemeral habitats such as the phytotalmanta of flower parts.
基金Helge Axelssons Johnsons stiftelse,Tullbergs för biologisk forskning stiftelse,Bertil Lundmans fond and Regnells botaniska resestipendium to A.P.Formas and the Swedish Research Council to J.Å.
文摘Aims Early models of plant defense conceived resistance and tolerance to herbivore damage as mutually exclusive strategies.support for this idea has been equivocal and studies on these two strategies are still needed to understand the evolution of defenses in natural populations.In Arabidopsis lyrata,the production of trichomes,a documented resistance trait,has been associated with a fitness cost in the absence of herbivores.We examined whether trichome production is also associated with reduced tolerance to simulated herbivore damage.Methods We conducted a field experiment in a natural swedish population of A.lyrata where we inflicted leaf(0 vs.50%of the area of each leaf removed)and inflorescence damage(0 vs.50%of inflores-cences removed)to trichome-producing and glabrous plants in a factorial design.We examined the response(survival,growth and reproduction)of the plants to the imposed damage over 2 years.Important Findingstrichome-producing plants were not less tolerant than glabrous plants to simulated herbivore damage(no significant morph×leaf damage or morph×inflorescence damage interactions).Inflorescence and leaf damage had independent negative effects on the performance of damaged plants.leaf damage reduced rosette size the year of damage,but effects on reproductive output in the year of damage,and on survival and reproductive performance the following year were weak and not statistically significant.Inflorescence damage significantly reduced the number of flowers,fruits and seeds the year of damage,but not in the following year.Irrespective of morph,the study population was more tolerant to leaf than to inflorescence damage.the results indicated no trade-off between trichome production and tolerance,suggesting that these two defense mechanisms have the potential to evolve indepen-dently in this A.lyrata population.
