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Picea abies (L.) Karst. and Pityogenes chalcographus constitute a commonly observed host treeâinsect association in Eurasia, with the natural distribution of the bark beetle overlapping that of Norway spruce. The southernmost borderline of their distributions occurs in the Elatia forest (Mt. Rodopi, Greece), where these interacting organisms may experience severe conditions due to the effects of climate change. In order to assess the dynamics of this host treeâinsect association, the genetic diversity of both organisms was studied. In contrast to previous studies, the assessment of molecular diversity was based on the same mitochondrial gene (Cytochrome Oxidase One) sequence for both host and pest. This analysis revealed a remarkably higher genetic diversity of P. chalcographus compared to that of P. abies, something that renders the insect capable not only of adapting to novel environmental conditions, but even of shifting to other host species. On the contrary, P. abies presented a narrow genetic base, a potential drawback at the southern-most region of the species natural distribution. Synthesizing the preliminary outcome for both organisms, it appears that P. chalcographus exhibits an evolutionary advantage over P. abies, something that should be considered when planning conservation strategies for the relict forest of Elatia.

The Asian chestnut gall wasp, Dryocosmus kuriphilus, is an invasive pest causing significant damage to chestnut trees (Castanea spp., Fagaceae). Originating from China, it has recently invaded a wide range of regions in Europe and North America. Understanding the population genetic structure of important invasive pests is very useful for improving the knowledge concerning routes of expansion and colonizing capacity. Despite its economic importance, limited attention has been given to D. kuriphilus origin and spread, or to its genetic structure. In this study, D. kuriphilus populations sampled in eight European countries were screened using both mitochondrial (cytochrome c oxidase subunit 1; COI) and nuclear (internal transcribed spacer 2; ITS2) sequences, and Amplified Fragment Length Polymorphism (AFLP) markers. The molecular markers COI and ITS2 highlighted the presence of a single haplotype in all the studied populations. The recorded mitochondrial haplotype was identical to one of the most widespread haplotypes occurring in the native area (China). AFLP results indicated that D. kuriphilus individuals belong to two genetically distinct clusters without any further geographic clustering. These results suggest that D. kuriphilus populations in Europe could be the result of a single introduction of a Chinese founder population characterized by two genetically distinct lineages that subsequently spread rapidly across Europe. However, the possibility that populations originated from multiple introductions of the same Chinese mitochondrial haplotype cannot be excluded. The reported results provide useful information concerning this invasive species, potentially facilitating integrated pest management. [ABSTRACT FROM AUTHOR]

Copyright of EPPO Bulletin is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of EPPO Bulletin is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The gypsy moth, a polyphagous herbivore species, infests mainly deciduous trees in the northern hemisphere, being invasive in North America. In Croatia, gypsy moth is infesting both continental and coastal forests, with the Dinaric Alps posing a physical migratory barrier between two regions. During outbreaks, caterpillars cause severe damages in both regions, though with different outbreak dynamics, which suggests genetic differences between populations. Representative populations from these two regions were screened by sequencing a region of the mitochondrial COI gene. Ninety-nine sequences resulted in seventeen haplotypes, and analyses revealed a significant genetic differentiation between coastal and continental populations, quite likely attributed to geographic isolation and post-glacial history. This differentiation arises from significantly higher genetic variability in Mediterranean population, indicating their higher adaptability, an intriguing fact in case of possible northward range shift of gypsy moth. [ABSTRACT FROM AUTHOR]

A unique logistic model for predicting population dynamics of Anarsia lineatella and Grapholita molesta was evaluated on populations sampled from Italy and Greece. Intraspecific mt DNA divergence was additionally estimated in an effort to examine whether regional differences in moth phenologies are associated with genetic divergence. A. lineatella populations displayed closer similarities on phenological responses between the two observation regions. As a result, population fluctuations in both regions could be accurately predicted based on the constructed model. However, that was not the case for G. molesta as its populations exhibited a more regional behaviour, and thus, the model was less accurate. It is notable that degree-day accumulations above the lower temperature thresholds were recorded in Italy on month earlier than in Greece (1st March in Calabria in contrast to 1st April in Veria). That kind of observed deviations in moth phenologies could be potentially attributed to regional environmental conditions or even genetic differentiation. Despite the low number of individuals analysed, this first attempt to study the levels of intraspecific divergence between Italian and Greek moth populations revealed that both species exhibit evidence of regional-based separation. Our study provides the first comprehensive phenological comparison between populations of A. lineatella and G. molesta from Italy and Greece. At the same time, the population genetic structure data reveal differentiation between these two regions for both species, something that should be further investigated as it could provide a possible explanation for the observed phenological differences. Moreover, DNA barcoding confirmed that G. molesta pheromone blends attracted at least two morphologically close-related tortricid moth species. This fact probably explains the phenological variations observed for this species as well as the difficulties in defining the number of non-overlapping flights. [ABSTRACT FROM AUTHOR]

Abstract: The effects of defoliation by the leaf mining moth Cameraria ohridella on seed germination were studied in Aesculus hippocastanum. Seedling vitality and survival were also examined in a 2-year experiment. Although C. ohridella infestation had a negative effect on seed fresh weight, seeds from infested trees presented higher field germination and germinated earlier than the seeds from noninfested trees. Seedlings of seeds from infested trees presented lower total height than those of seeds from noninfested trees in both years of the experiment. Moreover, in the first year of the experiment, the seedlings coming from infested trees presented lower values in all vitality parameters (shoot dry weight, root dry weight, overall dry biomass, shoot length, total length, root collar diameter, diameter at 5cm above root collar) except for the root length and the number of buds. In the second year of the experiment, the only vitality parameter that did not have lower value was the number of buds. Finally, seedlings survival did not show significant differences between the ones coming from infested and those from noninfested trees in both years of the experiment. [Copyright &y& Elsevier]