The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as S...The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as Serratia marcescens Bizio.This signifi cantly shortened the lifespan of hazelnut weevil.Larval weight was reduced as a function of S.marcescens concentration and exposure time.The structure of infected midgut cells was altered,with necrosis of the wall tissues and many cells becoming dislodged,creating cavities.The S.marcencens strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut weevil.Inhibition on S.marcencens strain increased with treatment time.S.marcescens directly destroyed the midgut cells and interfered with digestive and protective enzymes.This decreased the food intake and increased mortality of hazelnut weevil.S.marcescens appears to be an eff ective bacterium for the control of hazelnut weevil but requires further study,including biological formulation development and fi eld application.展开更多
Synchrony between seed growth and oogenesis is suggested to largely shape trophic breadth of seed-feeding insects and ultimately to contribute to their co-existence by means of resource partitioning or in the time whe...Synchrony between seed growth and oogenesis is suggested to largely shape trophic breadth of seed-feeding insects and ultimately to contribute to their co-existence by means of resource partitioning or in the time when infestation occurs.Here we investigated:(i)the role of seed phenology and sexual maturation of females in the host specificity of seed-feeding weevils(Curculio spp.)predating in hazel and oak mixed forests;and(ii)the consequences that trophic breadth and host distribution have in the genetic structure of the weevil populations.DNA analyses were used to establish unequivocally host specificity and to determine the population genetic structure.We identified 4 species with different specificity,namely Curculio nucum females matured earlier and infested a unique host(hazelnuts,Corylus avellana)while 3 species(Curculio venosus,Curculio glandium and Curculio elephas)predated upon the acorns of the 2 oaks(Quercus ilex and Quercus pubescens).The high specificity of C.nucum coupled with a more discontinuous distribution of hazel trees resulted in a significant genetic structure among sites.In addition,the presence of an excess of local rare haplotypes indicated that C.nucum populations went through genetic expansion after recent bottlenecks.Conversely,these effects were not observed in the more generalist Curculio glandium predating upon oaks.Ultimately,co-existence of weevil species in this multi-host-parasite system is influenced by both resource and time partitioning.To what extent the restriction in gene flow among C.nucum populations may have negative consequences for their persistence in a time of increasing disturbances(e.g.drought in Mediterranean areas)deserves further research.展开更多
基金the National Key Research and Development project of China(2016YFC0500308)Special Project for Double First-Class-Cultivation of Innovative Talents(000/41113102)+1 种基金the Natural Science Foundation of Heilongjiang Scientifi c Committee(C2018055)the Application Research Project of Heilongjiang Provincial Forest Industry Administration(sgzjY2014004).
文摘The hazelnut weevil(Curculio dieckmanni Faust.)is a major pest of Asian hazel(Corylus heterophylla Fisch.)in China.Dead hazelnut weevil larvae were examined and the associated pathogenic bacterium was identifi ed as Serratia marcescens Bizio.This signifi cantly shortened the lifespan of hazelnut weevil.Larval weight was reduced as a function of S.marcescens concentration and exposure time.The structure of infected midgut cells was altered,with necrosis of the wall tissues and many cells becoming dislodged,creating cavities.The S.marcencens strain inhibited digestive enzyme activity and protective enzymes in the midgut of adult hazelnut weevil.Inhibition on S.marcencens strain increased with treatment time.S.marcescens directly destroyed the midgut cells and interfered with digestive and protective enzymes.This decreased the food intake and increased mortality of hazelnut weevil.S.marcescens appears to be an eff ective bacterium for the control of hazelnut weevil but requires further study,including biological formulation development and fi eld application.
基金This research was supported by the projects FORASSEMBLY(CGL2015-70558-P)and PLAGANADO(AGL2014-54739-R)of the Spanish Ministry of Economythe projects BEEMED(SGR913)(Generalitat de Catalunya)and PII1C09-0256-9052(Regional Government of Castilla-La Mancha and the European Social Fund)R.B.was funded by a contract of the Program Atracción de Talento Investigador(Gobierno de Extremadura).
文摘Synchrony between seed growth and oogenesis is suggested to largely shape trophic breadth of seed-feeding insects and ultimately to contribute to their co-existence by means of resource partitioning or in the time when infestation occurs.Here we investigated:(i)the role of seed phenology and sexual maturation of females in the host specificity of seed-feeding weevils(Curculio spp.)predating in hazel and oak mixed forests;and(ii)the consequences that trophic breadth and host distribution have in the genetic structure of the weevil populations.DNA analyses were used to establish unequivocally host specificity and to determine the population genetic structure.We identified 4 species with different specificity,namely Curculio nucum females matured earlier and infested a unique host(hazelnuts,Corylus avellana)while 3 species(Curculio venosus,Curculio glandium and Curculio elephas)predated upon the acorns of the 2 oaks(Quercus ilex and Quercus pubescens).The high specificity of C.nucum coupled with a more discontinuous distribution of hazel trees resulted in a significant genetic structure among sites.In addition,the presence of an excess of local rare haplotypes indicated that C.nucum populations went through genetic expansion after recent bottlenecks.Conversely,these effects were not observed in the more generalist Curculio glandium predating upon oaks.Ultimately,co-existence of weevil species in this multi-host-parasite system is influenced by both resource and time partitioning.To what extent the restriction in gene flow among C.nucum populations may have negative consequences for their persistence in a time of increasing disturbances(e.g.drought in Mediterranean areas)deserves further research.
