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Suite à la découverte de l’expansion de la fourmi invasiveTapinoma magnumdans le sud-ouest (Lenoir& Galkowski, 2017), il apparaît que l’invasion se propage très vite dans cette région jusqu’à Toulouse ; elle atteint aussi la région lyonnaise, la vallée de la Loire et la Bretagne. Elle pose de graves problèmes comme à Saumur où les pelouses des maisons deviennent inabordables tellement il y a de fourmis. Deux autres espècesT. ibericumetT. darioi, se dispersent vers le nord mais ne semblent pas poser de problèmes graves pour le moment. La fourmi fantôme tropicaleT. melanocephalumcommence à être signalée dans les maisons ou appartements alors qu’elle était précédemment uniquement localisée dans des serres tropicales. On the expansion ofTapinomainvasive ants in France (Hymenoptera: Formicidae) The invasive antTapinoma magnumhas been reported in various places in southwestern France (Lenoir & Galkowski, 2017). This ant seems to spread rapidly in this region from Toulouse to Lyon region, as well as in the Loire Valley and Brittany. It is a big problem for example in Saumur where people cannot access their lawns. Two other species,T. ibericumandT. darioi, are reported from other places up North but do not present a threat currently. The tropical ghost antT. melanocephalumis also signaled in some places in houses or flats whereas it was only localized in tropical greenhouses.

Mycorrhizal symbiosis influences plant growth and nutrition and can affect the performance of insect herbivores, but these effects are context-dependent. This study aims to investigate the influence of nitrogen fertilization and mycorrhizal symbiosis on maize and Spodoptera exigua performance and to explore the potential underlying mechanisms. Mycorrhiza promoted maize growth and reduced S. exigua performance, but these effects were dependent on nitrogen availability. We then assessed whether the consequences for S. exigua were mediated by its gut microbiota. Neither nitrogen nor mycorrhization affected S. exigua gut bacterial community. Reduced herbivore performance was instead potentially due to the effects of nitrogen-mycorrhiza interaction on the plant nutritional value., This research has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Marie SkłodowskaCurie grant agreement no. 765290. MQ was funded by the Government of Asturias, FICYT and “Plan de Ciencia, Tecnologia e Innovacion 2018-2022” from the Government of Asturias [Grant AYUD/2021/58607].

International audience; This study presents research concerning subterranean termites found in the Centre-Val de Loire region. More specifically, we examined the geographical distribution of Reticulitermes flavipes, a globally invasive species. This work was conducted in collaboration with both social and life science specialists in order to better understand the factors mediating its spatial distribution. Using geomatics and the spatial analysis of R. flavipes' distribution, we were able to define geographical areas favorable to the termite. This geographical study and the diversity of players involved in this research underscore a growing awareness of termite invasion risks in society at large.

This study presents research concerning subterranean termites found in the Centre-Val de Loire region. More specifically, we examined the geographical distribution of Reticulitermes flavipes, a globally invasive species. This work was conducted in collaboration with both social and life science specialists in order to better understand the factors mediating its spatial distribution. Using geomatics and the spatial analysis of R. flavipes' distribution, we were able to define geographical areas favorable to the termite. This geographical study and the diversity of players involved in this research underscore a growing awareness of termite invasion risks in society at large.

International audience; In population genetics studies, detecting and quantifying the distribution ofgenetic variation can help elucidate ecological and evolutionary processes. Insocial insects, the distribution of population-level genetic variability is generallylinked to colony-level genetic structure. It is thus especially crucial to conductcomplementary analyses on such organisms to examine how spatial and socialconstraints interact to shape patterns of intraspecific diversity. In this study, wesequenced the mitochondrial COII gene for 52 colonies of the subterranean termiteReticulitermes grassei (Isoptera: Rhinotermitidae), sampled from a populationin southwestern France. Three haplotypes were detected, one of which wasfound exclusively in the southern part of the study area (near the Pyrenees).After genotyping 6 microsatellite loci for 512 individual termites, we detected asignificant degree of isolation by distance among individuals over the entirerange; however, the cline of genetic differentiation was not continuous, suggestingthe existence of differentiated populations. A spatial principal componentanalysis based on allele frequency data revealed significant spatial autocorrelationamong genotypes: the northern and southern groups were strongly differentiated.This finding was corroborated by clustering analyses; depending onthe randomized data set, two or three clusters, exhibiting significant degrees ofdifferentiation, were identified. An examination of colony breeding systemsshowed that colonies containing related neotenic reproductives were prevalent,suggesting that inbreeding may contribute to the high level of homozygosityobserved and thus enhance genetic contrasts among colonies. We discuss theeffect of evolutionary and environmental factors as well as reproductive anddispersal modes on population genetic structure.

International audience; Invasive species cause severe environmental and economic problems. The invasive success of social insects often appears to be related to their ability to adjust their social organization to new environments. To gain a better understanding of the biology of invasive termites, this studyinvestigated the social organization of the subterranean termite, Reticulitermes urbis, analyzing the breeding structure and the number of reproductives within colonies from three introduced populations. By using eight microsatellite loci to determine the genetic structure, it was found that all the colonies from the three populations were headed by both primary reproductives (kings and queens) and secondary reproductives (neotenics) to form extended-family colonies. R. urbis appears to be the only Reticulitermes species with a social organization based solely on extended-families in both native and introduced populations, suggesting that there is no change in their social organization on introduction. F-statistics indicated that there were few neotenics within the colonies from urban areas, which did not agree with results from previous studies and Þeld observations. This suggests that although several neotenics may be produced, only few become active reproductives. The results also imply that the invasive success of R. urbis may be based on different reproductive strategies in urban and semiurbanized areas. The factors inßuencing an individual to differentiate into a neotenic in Reticulitermes species are discussed

International audience