The Chalcidoidea bush of life: evolutionary history of a massive radiation of minute wasps.

Chalcidoidea are mostly parasitoid wasps that include as many as 500 000 estimated species. Capturing phylogenetic signal from such a massive radiation can be daunting. Chalcidoidea is an excellent example of a hyperdiverse group that has remained recalcitrant to phylogenetic resolution. We combined 1007 exons obtained with Anchored Hybrid Enrichment with 1048 ultra-conserved elements (UCEs) for 433 taxa including all extant families, >95% of all subfamilies, and 356 genera chosen to represent the vast diversity of the superfamily. Going back and forth between the molecular results and our collective knowledge of morphology and biology, we detected bias in the analyses that was driven by the saturation of nucleotide data. Our final results are based on a concatenated analysis of the least saturated exons and UCE datasets (2054 loci, 284 106 sites). Our analyses support an expected sister relationship with Mymarommatoidea. Seven previously recognized families were not monophyletic, so support for a new classification is discussed. Natural history in some cases would appear to be more informative than morphology, as illustrated by the elucidation of a clade of plant gall associates and a clade of taxa with planidial first-instar larvae. The phylogeny suggests a transition from smaller soft-bodied wasps to larger and more heavily sclerotized wasps, with egg parasitism as potentially ancestral for the entire superfamily. Deep divergences in Chalcidoidea coincide with an increase in insect families in the fossil record, and an early shift to phytophagy corresponds with the beginning of the "Angiosperm Terrestrial Revolution". Our dating analyses suggest a middle Jurassic origin of 174 Ma (167.3-180.5 Ma) and a crown age of 162.2 Ma (153.9-169.8 Ma) for Chalcidoidea. During the Cretaceous, Chalcidoidea may have undergone a rapid radiation in southern Gondwana with subsequent dispersals to the Northern Hemisphere. This scenario is discussed with regard to knowledge about the host taxa of chalcid wasps, their fossil record and Earth's palaeogeographic history

Isolation, characterization and PCR multiplexing of 17 microsatellite loci in the pine processionary moth <em>Thaumetopoea pityocampa</em> (Lepidoptera, Notodontidae)

International audienceSeventeen polymorphic microsatellite markers were developed for the pine processionary moth, Thaumetopoea pityocampa and organized in three multiplex.The number of alleles ranged from 1 to 18 and observed heterozygosities from 0.068 to 0.892. Tests of crossamplifications are also reported, and show that these loci can be used in divergent clades of the same species, and most of them for the sister species T. wilkinsoni. These markers will be useful to develop fine-scale population genetics study and adapt pest management strategies for this insect, which was proved to threaten relict pine populations in the Mediterranean Basin

Patterns of expansion of pine processionary moth at the northern edge of its distributional range

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Tracking the colonization patterns of an expanding forest pest and its natural enemies using molecular markers

International audienceClimate change is influencing population dynamics of several pest insect species leading to the expansion of their range. Range expansion can be driven also by human-mediated dispersal, with the establishment of new insect populations in suitable areas far from their native range. In this process, interactions between insects and their natural enemies can change due to new environmental conditions or to different rate of dispersion. In recent years, pine processionary moth (PPM), one of the main forest pests in the Mediterranean region, is expanding its range favored by both higher winter mean temperatures and accidental human-mediated transportation. Here we outlined the genetic structure of PPM along its range in France using 23 microsatellites loci, characterizing the main patterns of expansion of this species and identifying the source populations of new colonies in the expansion areas. These data can be employed for developing assignment tools to genetically characterize PPM for a quick identification of their origin area. Finally, we developed a new set of microsatellite primers for the PPM specialist egg-parasitoid in order to track its dispersion following its host in the expanding areas. The low genetic variability found, not directly useful for tracking parasitoid expansion, shed light on the role of bacterial endosymbionts in the population genetic structure of this species

Testing mito-nuclear discordance and <em>Wolbachia</em> hypothesis in a processionary moth contact zone

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Genetic Patterns In The Range Expansion Of Pine Processionary Moth In Northern France

International audienceSeveral studies have showed how climate change is affecting both distributional range and phenology of numerous insect species. Range expansion of different insect pests can be enhanced by human mediated dispersal with the settlement of new suitable areas far from the native range In particular, inter- and intra- continental ornamental plant trade seems to play a key role in the dispersal. The pine processionary moth, Thaumetopoea pityocampa, is one of the main pest attacking pine forests in southern Europe This species showed in the last decades a range expansion due to the recent climate changes. The spread of the moth seems to be also enhanced by both accidental human transportation linked to ornamental tree trade, and host tree distribution outside forests. In this study we analyzed the genetic variability of pine processionary moth populations in the front expansion edge as well as in other areas of the native range, using 24 microsatellite loci. The main expansion patterns were outlined in relation to the host plant distribution and other environmental factors

Sequence, assembly and count datasets of viruses associated to the pine processionary moth Thaumetopoea pityocampa (Denis &amp; Schiffermüller) (Lepidoptera, Notodontidae) identified from transcriptomic high-throughput sequencing

The pine processionary moth Thaumetopoea pityocampa is a Lepidopteran pest species occurring in the Western Mediterranean. It causes heavy pine defoliations and it is a public and animal health concern because of its urticating caterpillars. Very little is known about the viruses associated to this species, as only two viruses were described so far. We here present a dataset corresponding to 34 viral transcripts, among which 27 could be confidently assigned to 9 RNA and DNA viral families (Iflaviridae, Reoviridae, Partitiviridae, Permutotetraviridae, Flaviviridae, Rhabdoviridae, Parvoviridae, Baculoviridae and PolyDNAviridae). These transcripts were identified from an original transcriptome assembled for the insect host, using both blast search and phylogenetic approaches. The data were acquired from 2 populations in Portugal and 2 populations in Italy. The transcripts were de novo assembled and used to identify viral sequences by homology searches. We also provide information about the populations and life stages in which each virus was identified. The data produced will allow to enrich the virus taxonomy in Lepidopteran hosts, and to develop PCR-based diagnostic tools to screen colonies across the range and determine the distribution and prevalence of the identified viral species

Empirical assessment of RAD sequencing for interspecific phylogeny

International audienceNext-generation sequencing opened up new possibilities in phylogenetics; however, choosing an appropriate method of sample preparation remains challenging. Here, we demonstrate that restriction-site-associated DNA sequencing (RAD-seq) generates useful data for phylogenomics. Analysis of our RAD library using current bioinformatic and phylogenetic tools produced 400x more sites than our Sanger approach (2,262,825 nt/species), fully resolving relationships between 18 species of ground beetles (divergences up to 17 My). This suggests that RAD-seq is promising to infer phylogeny of eukaryotic species, though potential biases need to be evaluated and new methodologies developed to take full advantage of such data

A first inference of the phylogeography of the worldwide invader Xylosandrus compactus

International audienceNative to Southeastern Asia, the ambrosia beetle Xylosandrus compactus is invasive worldwide. Its invasion is favoured by its cryptic lifestyle, symbiosis with a fungus that facilitates a broad range of host plants, and predominant sib-mating reproduction. X. compactus invaded Africa more than a century ago and the Americas and Pacific Islands in the middle of the twentieth century. It was not detected in Europe before 2011, when it was first reported in Italy before quickly spreading to France, Greece and Spain. Despite the negative environmental, agricultural and economic consequences of the invasion of X. compactus, its invasion history and main pathways remain poorly documented. We used COI and RAD sequencing to (i) characterise the worldwide genetic structure of the species, (ii) disentangle the origin(s) of the non-native populations on the three invaded continents and (iii) analyse the genetic diversity and pathways within each invaded region. Three mitochondrial lineages were identified in the native range. Populations invading Europe and the American-Pacific region originated from the first lineage and were only slightly genetically differentiated at nuclear SNP markers, suggesting independent introductions from close sources in or near Shanghai, ca. 60 years apart. Populations invading Africa originated from the second lineage, likely from India or Vietnam