远东地区影响针叶树天然更新的球果种实害虫———球果花蝇 (双翅目 :花蝇科)( 英文)

球果花蝇是远东地区的重要球果种实害虫。尤其是在我国东北地区 ,由于球果花蝇的危害已严重影响了落叶松种子产量 ,进而影响到落叶松的造林与更新。本文系统地总结了近些年危害落叶松、云杉、冷杉种实的球果花蝇的研究进展及存在的问题。文中还涵括了作者的一些原始研究数据和尚未发表的新结果。

Direct impacts of recent climate warming on insect populations

Effects of recent climate change have already been detected in many species,and,in particular,in insects.The present paper reviews the key impacts of global warming on insect development and dispersal.The effects of climate change appear to be much more complex than a simple linear response to an average increase in temperature.They can differ between seasons and bioclimatic regions.Earlier flight periods,enhanced winter survival and acceleration of development rates are the major insect responses.Differential response of insects and hosts to warming up might also lead to disruption of their phenological synchrony,but adaptive genetic processes are likely to quickly restore this synchrony.In a number of cases,warming results in removing or relocating the barriers that limit present species’ranges.It is also likely to facilitate the establishment and spread of invasive alien species.Finally,knowledge gaps are identified and future research interests are suggested.

Is the expansion of the pine processionary moth, due to global warming, impacting the endangered Spanish moon moth through an induced change in food quality?

Recent climate change is known to affect the distribution of a number of insect species,resulting in a modifica­tion of their range boundaries.In newly colonized areas,novel interactions become apparent between expanding and endemic species sharing the same host.The pine processionary moth is a highly damaging pine defoliator,extending its range northwards and upwards in response to winter warming.Its expansion in the Alps has result­ed in an invasion into the range of the Spanish moon moth,a red listed species developing on Scots pine.Pine processionary moth larvae develop during winter,preceding those of the moon moth,which hatch in late spring.Using pine trees planted in a clonal design,we experimentally tested the effect of previous winter defoliation by pine processionary moth larvae upon the survival and development of moon moth larvae.Feeding on foliage of heavily defoliated trees(>50%)resulted in a significant increase in the development time of moon moth larvae and a decrease in relative growth rate compared to feeding on foliage of undefoliated trees.Dry weight of pupae also decreased when larvae were fed with foliage of defoliated trees,and might,therefore,affect imago perfor­mances.However,lower defoliation degrees did not result in significant differences in larval performances com­pared to the control.Because a high degree of defoliation by pine processionary moth is to be expected during the colonization phase,its arrival in subalpine pine stands might affect the populations of the endangered moon moth .

Size and dispersion of urticating setae in three species of processionary moths

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.

Seed wasp invasions promoted by unregulated seed trade affect vegetal and animal biodiversity

Cone and seed insects are considered the most important predators of tree seeds during the pre-dispersal phase of development.Among them,exotic seed chalcids in the genus Megastigmus invaded Europe as a result of the rapidly-increasing and mostly unregulated seed trade for afforestation and ornamental plantations.Unlike their economic impact in seed orchards,until recently,little attention was paid to the ecological impact of these insects.In the present study,selected case studies of alien Megastigmus spp.were considered to assess their specific impact on the potential of natural regeneration of native woody plants and on the native entomofauna competing for seed resource.We re-analyzed data from former studies that did not focus on these ecological interactions and,here,present previously unpublished results.Seeds of Douglas-fir,true cedars,true firs and wild roses were sampled all over Europe,and the relative importance of the native and invasive chalcid species was assessed as well as their specific impact on seed yield.In most cases,the recent arrival of alien chalcids resulted in a significant decrease in the regeneration potential of the host trees.In the absence of competitors,alien chalcids occupied the entire seed niche in Douglas-fir,but their impact tended to decrease after the arrival of invasive seed bugs.In firs,alien chalcids tended to displace the native chalcids,but not in wild roses and cedars,where their damage was increasing.Different biological traits that might explain invasive success of alien chalcids are discussed.However,no general invasive patterns seem to exist.

Biological invasion

Biological invasions are without any contest recognized as a major driver of global change.Expanding world-wide trade,globalization of economies and climate change are all factors that contribute to an accelerated international movement and establishment of alien organisms,allowing them to overcome geographic barriers.Actually,there is no indication of a possible decrease in the ever-accelerating rate of introduction of alien species which has been observed since several decades.