Cette présentation s'inscrit dans le cadre d'une journée d'accélération du secteur Audiovisuel du Programme de recherche Industries culturelles et créatives (PEPR ICCARE), intitulée "Production légère et sobriété économique — Propositions communes pour un autre cinéma".

Wild silkmoths (Saturniidae) are one of the most emblematic and well-studied families of moths. Yet, the absence of a robust phylogenetic framework based on a comprehensive taxonomic sampling impedes our understanding of their evolutionary history. We sequenced and analyzed 1024 ultraconserved elements (UCEs) and their flanking regions to infer the relationships among 338 species of Saturniidae representing all described subfamilies, tribes, and genera. We investigated systematic biases in genomic data and performed dating and historical biogeographic analyses using extinction-free and state-dependent speciation and extinction models to document the evolutionary history of wild silkmoths in space and time. Using gene genealogy interrogation, we showed that saturation of nucleotide sequence data blurs our understanding of early divergences and first biogeographic events. Our results support a Neotropical origin of saturniids but remain inconclusive with respect to the extent of the ancestral range for the family. The “traditional” hypothesis of an origin restricted to the Neotropics is supported by models that account for founder-effect dispersal, but a new alternative scenario recovered from other models is proposed and considered a better fit to the hypothetical modes of diversification in these moths. It estimates a broader ancestral range covering the Neotropical, West Nearctic, and East Palearctic bioregions and emphasizes the critical role of Beringia as a route between the New World and the Old World during the Eocene. Interestingly, all the early branching lineages of Saturniidae that diversified into today’s recognized subfamilies are characterized by a very strong geographic conservatism, except for one noticeable exception, the Saturniinae subfamily, that is now present on all continents but Antarctica. Overall, our results provide a framework for in-depth investigations into the spatial and temporal dynamics of all saturniid lineages and for the integration of their evolutionary history into further global studies of biodiversity and conservation. Rather unexpectedly for a taxonomically well-known family such as Saturniidae, the proper alignment of taxonomic divisions and ranks with our phylogenetic results leads us to propose substantial rearrangements of the family classification, including the description of one new subfamily and two new tribes.

[...]

La mémoire collective l’a bien oublié, mais le bagne fut une réponse administrative et judiciaire aux poly-condamnés français des XIXe et XXe siècles. Les écrits de Henri Charrière (1906-1973) dit Papillon, adaptés deux fois au cinéma, ainsi que le reportage photographique du médecin saône-et-loirien Léon Collin (1880-1970) donnent un aperçu de cette époque révolue où l’on pouvait être condamné à la déportation et à la relégation à des milliers de kilomètres de la métropole. Parmi ces condamnés figure Jean-Baptiste Courtot (1859-1893) qui, après un énième vol, fut envoyé en 1893 en Guyane française. Il s’enfuira du camp peu après son arrivée et mourra dans la forêt équatoriale. Courtot est le seul bagnard connu de Meursault.

The genus Ostrinia (Lepidoptera: Crambidae) comprises two of the most important maize pests worldwide, the Asian and the European corn borers. Here, we present an annotated, chromosome-level genome assembly for the most closely related species, the Adzuki bean borer Ostrinia scapulalis, which feeds on various dicotyledon plants. The previous reference genome assembly for this species was generated from short-read sequencing data, resulting in high fragmentation and low completeness. Combining PacBio long read and Hi-C sequencing, we generated a 476 Mb genome with 48 contigs organised into 31 chromosomes (30 autosomes and one Z sex chromosome), with a contig N50 of 16.1 Mbp and BUSCO completeness exceeding 98%. We further combined published and novel RNA-seq data encompassing multiple life stages, tissues, and sexes to annotate 14,261 gene models, reaching a proteome BUSCO completeness of 95%. This highly contiguous reference genome assembly provides a much-improved resource for carrying comparative genomic approaches and better understanding speciation and host plant adaptation in the Ostrinia genus

Mate finding in most moths is based on male perception of a female-emitted pheromone whose species specificity resides in component chemistry and proportions. Components are individually detected by specialized olfactory receptor neurons (ORNs) projecting into the macroglomerular complex (MGC) of the male brain. We asked how robust ratio recognition is when challenged by a plant volatile background. To test this, we investigated the perception of the pheromone blend in Agrotis ipsilon, a moth species whose females produce a blend of Z7-dodecenyl acetate (Z7-12:Ac), Z9-tetradecenyl acetate (Z9-14:Ac), and Z11-hexadecenyl acetate in a 4:1:4 ratio optimally attractive for males. First, we recorded the responses of specialist ORNs for Z7 and Z9 and showed that heptanal, a flower volatile, activated Z7 but not Z9 neurons. Then, we recorded intracellularly the responses of MGC neurons to various ratios and showed that heptanal altered ratio responses of pheromone-sensitive neurons. Finally, we analyzed the behavior of males in a wind tunnel and showed that their innate preference for the 4:1:4 blend was shifted in the presence of heptanal. Pheromone ratio recognition may thus be altered by background odorants. Therefore, the olfactory environment might be a selective force for the evolution of pheromone communication systems.

The cotton leafworm, Spodoptera littoralis (Lepidoptera: Noctuidae), is a major agricultural pest affecting crops like cotton, maize, tomatoes, and wheat across southern Europe, Africa, the Middle East, and western Asia. Whole genome analyses have revealed adaptive evolution in chemosensation and detoxification genes in S. littoralis. However, the extent of intraspecific diversity influenced by recent adaptive evolutionary forces remains unclear. In this study, we conducted a population genomics analysis using 31 S. littoralis individuals from sub-Saharan Africa, northern Africa, and southern Europe to assess the existence of intraspecific population divergence and identify the underlying evolutionary forces. We show whole genome differentiation between populations based on geographic origin from the analyzed samples. Phylogenetic analyses indicate that sub-Saharan and southern European populations share a common ancestor, distinct from several northern African populations. FST and dXY statistics along the chromosomes reveal loci with restricted gene flow among populations. These loci are associated with population-specific selective sweeps, indicating the role of divergent natural selection in limiting gene flow. Notably, these loci are enriched with detoxification genes, including cytochrome P450, multidrug resistance, and xanthine dehydrogenase genes, all of which are potentially associated with detoxification. These results demonstrate that divergent selection limits gene flow among geographically distinct populations with the possibility of the involvement of detoxification as a key trait. We argue that this genetic heterogeneity can be considered in pest monitoring and management, as strategies tailored to specific populations may not be relevant for others.

We present the first nuclear genome assembly and a complete mitogenome for Hylesia metabus (Arthropoda; Insecta; Lepidoptera; Saturniidae). The assembled nuclear genome sequence is 1,271 Mb long, which is among the 10 largest lepidopteran genome assemblies published to date. It is scaffolded in 31 pseudo chromosomes, has a BUSCO score of 99.5%, and has a highly conserved synteny compared to phylogenetically close species. Repetitive elements make up 67% of the nuclear genome and are mainly located in intergenic regions, among which LINEs were predominant, with CR1-Zenon being the most abundant. Phylogenetic and comparative analyses of H. metabus assembly and 17 additional Saturniidae and Sphingidae assemblies suggested that an accumulation of repetitive elements likely led to the increased size of H. metabus’ genome. Gene annotation using Helixer identified 26,122 transcripts. The Z scaffold was identified using both a synteny analysis and variations of coverage for two resequenced male and female H. metabus . The H. metabus nuclear genome and mitogenome assemblies can be found and browsed on the BIPAA website and constitute useful resources for future population and comparative genomics studies.

We present the first chromosome-level genome assembly and annotation of the pearly heath Coenonympha arcania, generated with a PacBio HiFi sequencing approach and complemented with Hi-C data. We additionally compare synteny, gene, and repeat content between C. arcania and other Lepidopteran genomes. This reference genome will enable future population genomics studies with Coenonympha butterflies, a species-rich genus that encompasses some of the most highly endangered butterfly taxa in Europe.