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Genetics and genomics of pine processionary moths and their parasitoids
Full text linkThe pine processionary moth (Thaumetopoea spp.), an important defoliator of Pinus spp. in the Mediterranean area, is recently expanding its range in response to climate change and anthropogenic factors. Therefore it's important to outline the way in which this pest can colonize new areas, and to do this molecular markers seem to be the most suitable tools. In the introduction I present some of the molecular markers used in the last years to study ecological and evolutionary problems related to insects. The main aim of my work was to analyze the genetic variability of pine processionary moth in its present range and so to try to reconstruct the recent and past colonization history of this pest. Secondly, another goal was to characterize the genetic structure of pine processionary moth parasitoids to better understand the factors involved in their differentiation such as in tracking their host on different pine species.
In the first study I extended a work already begun on the population genetic of pine processionary moth to the populations of the Near East. The main issue of this study was to understand the origin of population attacking the Israel pine plantations and in second place to genetically characterize all the populations in the range. Moreover, this study shows the utility of the use of both nuclear and mitochondrial markers for the different information they can yield. In this case they permitted to track a gender-related dispersal, which could be important to maintain genetic variability in expansion areas.
In the second study, I contributed to outline the genetic structure of pine processionary moth in the whole range. Through the mitochondrial markers used in the previous studies it was possible to define the main events occurred to this species in the past, identifying glacial refugia and the main splitting events among the different lineages. In northern Africa, a new unexpected genetic clade was found analyzing populations that were previously considered, on a morphological base, to belong to a subspecies of the two already described pine processionary moth species.
In the third study, I contributed to the sequencing of the entire mitochondrial genome of Ochrogaster lunifer, an Australian species belonging to the same subfamily of the pine processionary moth. This study, besides to represent the first step to have insights into the taxonomy of the family, gave useful information about the best markers to be used in population genetic studies on Lepidoptera.
In the fourth study, I dealt with the population genetic of two egg parasitoid species of the pine processionary moth: the specialist Baryscapus servadeii and the generalist Ooencyrtus pityocampae. The main goal of this study was to test the presence of a host plant association in these two parasitoids and to compare the genetic patterns of a specialist and a generalist. In the specialist parasitoid populations analyzed it seems to be present a genotype mostly associated with the host plant. Moreover, unlike the generalist, the specialist doesn’t show to have a genetic pattern spatially structured.
This could be related to a higher mobility of the specialist, and hence to its strategy in finding hosts. These findings provide useful information to predict the behavior of parasitoids in expanding areas. On the whole, the four contributions provide suggestions for the range wide management of the pest, and insights into the evolutionary history of the group, including projections on the potential for adaptation to ongoing climate change.La processionaria del pino (Thaumetopoea spp.), un importante defogliatore dei pini in tutta l’area del Mediterraneo, ha mostrato, nel corso degli ultimi decenni, un’espansione del suo areale in risposta sia al cambiamento climatico che a fattori antropici. E' quindi importante delineare le modalità con cui questa specie riesce a colonizzare nuove aree e per far questo i marcatori molecolari sembrano essere gli strumenti più utili. Nell’introduzione sono presentate alcuni dei marcatori molecolari usati negli ultimi anni per studiare problemi ecologici ed evolutivi in relazione agli insetti. L'obiettivo principale del mio lavoro è consistito nell’analizzare la variabilità genetica della processionaria del pino nel suo attuale areale e nel tentare di ricostruire la storia della sua colonizzazione recente e passata. In secondo luogo, un ulteriore obiettivo è stato quello di caratterizzare la struttura genetica di alcuni parassitoidi della processionaria del pino per comprendere meglio quali sono i fattori coinvolti nel loro differenziamento quale può essere la ricerca dell’ospite su diverse specie di pino.
Nel primo lavoro ho esteso a popolazioni del Vicino Oriente uno studio già iniziato sulla genetica di popolazione della processionaria del pino. Lo scopo principale di questo lavoro era quello di capire l’origine delle popolazioni che attaccano le piantagioni di pino in Israele e in secondo luogo di caratterizzare geneticamente tutte le popolazioni presenti nella regione. Questo studio ha inoltre mostrato l'utilità dell'impiego di marcatori mitocondriali e nucleari per il diverso tipo di informazione che possono produrre. In questo caso è stato possibile individuare una dispersione in relazione al sesso degli individui, processo che potrebbe essere importante per il mantenimento della variabilità genetica nelle aree di espansione.
Nel secondo lavoro, è stata delineata la struttura genetica della processionaria del pino in tutto il suo areale. Attraverso i marcatori mitocondriali utilizzati nello studio precedente è stato possibile definire per questa specie i principali eventi occorsi nel passato, identificando così i rifugi glaciali e i principali eventi di separazione tra le diverse popolazioni. Nel Nord Africa, è stato individuato in questo modo un nuovo clade geneticamente ben definito, analizzando popolazioni precedentemente considerate, su base morfologica, appartenenti ad una sottospecie di una della due specie di processionaria già descritte.
Nel terzo lavoro, è stato descritto l’intero menoma mitocondriale di ochrogaster lunifer, una specie Australina appartenete alla stessa sottofamiglia della processionaria del pino. Questo studio, oltre a rappresentare il primo passo per un chiarimento della tassonomia di questa famiglia di Lepidotteri, ha prodotto informazioni utili riguardo ai marcatori che possono essere utilizzati negli studi di genetica di popolazione dei Lepidotteri.
Nel quarto lavoro, ho preso in considerazione la genetica di popolazione di due parassitoidi oofagi della processionaria del pino: lo specialista Baryscapus servadeii e il generalista Ooencyrtus pityocampae. L’obiettivo principale di questo studio era di testare la presenza di un’associazione con la pianta ospite in questi due parassitoidi e di comparare inoltre la struttura genetica di uno specialista con quella di un generalista. Nelle popolazioni del parassitoide specialista analizzate sembra essere presente un genotipo per lo più associato con una delle piante ospiti della processionaria. Inoltre, a differenza del generalista, il parassitoide specialista non presenta una variabilità genetica strutturata spazialmente. Questo potrebbe essere messo in relazione alla più alta mobilità dello specialista e quindi alla sua strategia per individuare l’ospite. Tali nuove informazioni su questi parassitoidi possono rivelarsi utili nel predire il loro comportamento nelle aree di espansione.
Nel complesso, i quattro contributi presentati qui forniscono suggerimenti per il controllo di questo insetto infestante su larga scala e una maggiore conoscenza della storia evolutiva del gruppo, includendo inoltre delle previsioni sul potenziale di adattamento di queste specie in relazione ai cambiamenti climatici in corso
First record of Ambrosiodmus (Hopkins, 1915) (Coleoptera: Curculionidae, Scolytinae) in Europe
No full textFaccoli, Massimo, Frigimelica, Gabriella, Mori, Nicola, Toffolo, Edoardo Petrucco, Vettorazzo, Marco, Simonato, Mauro (2009): First record of Ambrosiodmus (Hopkins, 1915) (Coleoptera: Curculionidae, Scolytinae) in Europe. Zootaxa 2303: 57-60, DOI: 10.5281/zenodo.27532
FIGURE 1 in First record of Ambrosiodmus (Hopkins, 1915) (Coleoptera: Curculionidae, Scolytinae) in Europe
No full textFIGURE 1. Ambrosiodmus rubricollis (Eichhoff, 1875): a, female, dorsal habitus; b, female pronotum, dorsal view; c, male, dorsal habitus; d, female pronotum, lateral view.Published as part of Faccoli, Massimo, Frigimelica, Gabriella, Mori, Nicola, Toffolo, Edoardo Petrucco, Vettorazzo, Marco & Simonato, Mauro, 2009, First record of Ambrosiodmus (Hopkins, 1915) (Coleoptera: Curculionidae, Scolytinae) in Europe, pp. 57-60 in Zootaxa 2303 on page 58, DOI: 10.5281/zenodo.27532
First record of Cyrtogenius strohmeyer in Europe, with a key to the European genera of the tribe Dryocoetini (coleoptera: Curculionidae, scolytinae)
No full textThe genus Cyrtogenius Strohmeyer, represented by the species C. luteus (Blandford, 1894), is reported for the first time in Europe. Many adults were collected for four consecutive years (2009-2012) in various localities of northern Italy in both multifunnel and cross-vane traps baited with multilure blends. A diagnosis of the species and a revised key to the European genera of tribe Dryocoetini Lindemann is also reported. An explanation is suggested for the increasing number of recent introductions of exotic scolytids into Europe. Copyright © 2012 Magnolia Press
Cyrtogenius Strohmeyer 1910
No full text<i>Cyrtogenius</i> Strohmeyer, 1910 <p> The genus <i>Cyrtogenius</i> includes about 90 species, mainly from Oceania and Micronesia (about 49), 25 from Africa and about 16 from Asia (Wood & Bright 1992). <i>Cyrtogenius</i> species are largely tropical in their distribution, and some breed in seeds or in the pith of twigs, rather than in phloem. The majority of the species are, however, true bark beetles (phloeophagous). Very few of them (<i>C. luteus</i> and <i>C. philippinensis</i>) are associated with conifers, with a strong preference for pines, whereas all other species develop in tropical broadleave trees and lianas. For the majority of <i>Cyrtogenius</i> species (about 65%) the host plant is still unknown (Wood & Bright 1992). Some <i>Cyrtogenius</i> species are known to be heterosanguineously polygynous (Wood 1986).</p>Published as part of <i>Faccoli, Massimo, Simonato, Mauro & Toffolo, Edoardo Petrucco, 2012, First record of Cyrtogenius Strohmeyer in Europe, with a key to the European genera of the tribe Dryocoetini (Coleoptera: Curculionidae, Scolytinae), pp. 27-35 in Zootaxa 3423</i> on page 28, DOI: <a href="http://zenodo.org/record/215247">10.5281/zenodo.215247</a>
The complete mitochondrial genome of the bag-shelter moth <it>Ochrogaster lunifer </it>(Lepidoptera, Notodontidae)
Full text linkAbstract Background Knowledge of animal mitochondrial genomes is very important to understand their molecular evolution as well as for phylogenetic and population genetic studies. The Lepidoptera encompasses more than 160,000 described species and is one of the largest insect orders. To date only nine lepidopteran mitochondrial DNAs have been fully and two others partly sequenced. Furthermore the taxon sampling is very scant. Thus advance of lepidopteran mitogenomics deeply requires new genomes derived from a broad taxon sampling. In present work we describe the mitochondrial genome of the moth Ochrogaster lunifer. Results The mitochondrial genome of O. lunifer is a circular molecule 15593 bp long. It includes the entire set of 37 genes usually present in animal mitochondrial genomes. It contains also 7 intergenic spacers. The gene order of the newly sequenced genome is that typical for Lepidoptera and differs from the insect ancestral type for the placement of trnM. The 77.84% A+T content of its α strand is the lowest among known lepidopteran genomes. The mitochondrial genome of O. lunifer exhibits one of the most marked C-skew among available insect Pterygota genomes. The protein-coding genes have typical mitochondrial start codons except for cox1 that present an unusual CGA. The O. lunifer genome exhibits the less biased synonymous codon usage among lepidopterans. Comparative genomics analysis study identified atp6, cox1, cox2 as cox3, cob, nad1, nad2, nad4, and nad5 as potential markers for population genetics/phylogenetics studies. A peculiar feature of O. lunifer mitochondrial genome it that the intergenic spacers are mostly made by repetitive sequences. Conclusion The mitochondrial genome of O. lunifer is the first representative of superfamily Noctuoidea that account for about 40% of all described Lepidoptera. New genome shares many features with other known lepidopteran genomes. It differs however for its low A+T content and marked C-skew. Compared to other lepidopteran genomes it is less biased in synonymous codon usage. Comparative evolutionary analysis of lepidopteran mitochondrial genomes allowed the identification of previously neglected coding genes as potential phylogenetic markers. Presence of repetitive elements in intergenic spacers of O. lunifer genome supports the role of DNA slippage as possible mechanism to produce spacers during replication.</p
First record of thousand cankers disease fungal pathogen Geosmithia morbida and walnut twig beetle Pityophthorus juglandis on Juglans regia in Europe
No full textTesting for host-associated differentiation in two egg parasitoids of a forest herbivore
No full textSeveral studies underline the importance of ecological barriers and differential selection in driving sympatric speciation. Host-associated differentiation (HAD) has been proposed as one of the mechanisms leading to sympatric speciation. However, it is still unclear how common HAD is or which are the factors that could promote it. In particular, not much is known about HAD in predators and parasitoids of herbivorous insects. One of the characteristics postulated to pre-dispose insects to HAD is parthenogenesis as it may favour adaptive responses to particular environments, amplifying selected gene complexes. In this study, we used amplified fragment length polymorphism (AFLP) markers to determine whether HAD is present in two parthenogenetic egg parasitoids attacking the same herbivore species – the pine processionary moth, Thaumetopoea pityocampa (Denis & Schiffermüller) (Lepidoptera: Notodontidae) – on two host Pinus species. A total of 100 loci for 59 individuals sampled in four populations of Baryscapus servadeii (Domenichini) (Hymenoptera: Eulophidae), a specialist parasitoid, and 106 loci for 117 individuals sampled in six populations of Ooencyrtus pityocampae Mercet (Hymenoptera: Encyrtidae), a generalist parasitoid, were analysed. Levels of genetic differentiation were also assessed with an outlier analysis, checking for alleles associated to host plants. No evidence of HAD was detected in any of the two parasitoid species. We hypothesize that both the lack of strict parthenogenetic reproduction and the ectophagous nature of the insect host could explain the absence of HAD. The genetic variation observed in the generalist parasitoid responded to a pattern of local adaptation, whereas no relationship with either host or geography was found in the specialist parasitoid
Comunità batteriche associate a popolazioni naturali di Drosophila suzukii nell'areale di invasione
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