Tree colonization and feeding activity of the invasive wood-borer Asian longhorn beetle （Anoplophora glabripennis）, an Asian pest introduced into North America and Europe, was studied in a newly invaded area in Ital...Tree colonization and feeding activity of the invasive wood-borer Asian longhorn beetle （Anoplophora glabripennis）, an Asian pest introduced into North America and Europe, was studied in a newly invaded area in Italy. The hypothesis be- ing tested was that the reproductive success of the insect depend on habitat type and tree suitability. Adult beetles were caged on branches of host and nonhost species, in both urban and forest habitats. Two months later, number and size of feeding patches on plant tissues, eggs laid, and surviving larvae were assessed. Bark concentration of C and N was also measured from the same trees. Results indicated that the mean area of plant tissues consumed by adult feeding was significantly larger on trees growing in forest than in urban habitat, although within the same habitat there were no differences between susceptible and nonsusceptible trees. ALB tree colonization, in terms of number of eggs laid and young larvae survival, was not affected by habitat while it was higher on susceptible trees. Although trees growing in forests had a lower nitrogen concentration, they allowed colo- nization rates similar to those of trees growing in the urban habitat. Hence, the amount of carbon and nitrogen did not fully explain tree suitability or habitat selection. We suggest compensatory feeding as a potential mechanism that might explain this peculiar situation, as supported by a more intensive feeding activity recorded on trees in the forest. Suitability of different trees may be due to other factors, such as secondary chemical compounds.展开更多
Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees a...Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees and,consequently,may threaten human and animal health during outbreaks,causing dermatitis,conjunctivitis and respiratory distress.Although some studies provide detailed information about the setae,particularly those of the pine processionary moth Thaumetopoea pityocampa,there is little knowledge on the morphological traits of the setae and their release by the larvae.In the present study we identify major traits of the setae of 3 species of processionary moth,T.pityocampa,T.pinivora and T.processionea,which are potentially helpful in the understanding of setae dynamics in the environment:(i)diameter and length of setae and(ii)analysis of dynamical properties of the setae in the airborne state.Setae are highly variable in size,with bimodal distribution in T.pityocampa and T.pinivora;in these 2 species,short and long setae are interspersed within the integument fields where they occur.The difference in the seta size has important consequences in dispersion,as smaller setae can spread 5 times further than their bigger counterparts.This information is relevant for a full understanding of the defensive importance of larval setae against natural enemies of the processionary moths,as well for elucidating the importance of the processionary setae as air pollutants,both close to the infested trees and at longer distances.展开更多
文摘Tree colonization and feeding activity of the invasive wood-borer Asian longhorn beetle （Anoplophora glabripennis）, an Asian pest introduced into North America and Europe, was studied in a newly invaded area in Italy. The hypothesis be- ing tested was that the reproductive success of the insect depend on habitat type and tree suitability. Adult beetles were caged on branches of host and nonhost species, in both urban and forest habitats. Two months later, number and size of feeding patches on plant tissues, eggs laid, and surviving larvae were assessed. Bark concentration of C and N was also measured from the same trees. Results indicated that the mean area of plant tissues consumed by adult feeding was significantly larger on trees growing in forest than in urban habitat, although within the same habitat there were no differences between susceptible and nonsusceptible trees. ALB tree colonization, in terms of number of eggs laid and young larvae survival, was not affected by habitat while it was higher on susceptible trees. Although trees growing in forests had a lower nitrogen concentration, they allowed colo- nization rates similar to those of trees growing in the urban habitat. Hence, the amount of carbon and nitrogen did not fully explain tree suitability or habitat selection. We suggest compensatory feeding as a potential mechanism that might explain this peculiar situation, as supported by a more intensive feeding activity recorded on trees in the forest. Suitability of different trees may be due to other factors, such as secondary chemical compounds.
基金This work was funded by the French National Research Agency in the framework of project ANR No.07BDIV 013‘URTICLIM’by the University of Padova grant 2010-C91J10000320001.
文摘Larvae of the processionary moths of the Palaearctic region bear urticating setae that are released against vertebrate predators,especially insectivorous birds.A few species are pests of forest and urban trees and,consequently,may threaten human and animal health during outbreaks,causing dermatitis,conjunctivitis and respiratory distress.Although some studies provide detailed information about the setae,particularly those of the pine processionary moth Thaumetopoea pityocampa,there is little knowledge on the morphological traits of the setae and their release by the larvae.In the present study we identify major traits of the setae of 3 species of processionary moth,T.pityocampa,T.pinivora and T.processionea,which are potentially helpful in the understanding of setae dynamics in the environment:(i)diameter and length of setae and(ii)analysis of dynamical properties of the setae in the airborne state.Setae are highly variable in size,with bimodal distribution in T.pityocampa and T.pinivora;in these 2 species,short and long setae are interspersed within the integument fields where they occur.The difference in the seta size has important consequences in dispersion,as smaller setae can spread 5 times further than their bigger counterparts.This information is relevant for a full understanding of the defensive importance of larval setae against natural enemies of the processionary moths,as well for elucidating the importance of the processionary setae as air pollutants,both close to the infested trees and at longer distances.
