Climate-induced forest dieback drives compositional changes in insect communities that are more pronounced for rare species

Species richness, abundance and biomass of insects have recently undergone marked declines in Europe. We metabarcoded 211 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging had an impact on ca. 3000 species of flying insects in silver fir Pyrenean forests. While forest dieback had no measurable impact on species richness, there were significant changes in community composition that were consistent with those observed during natural forest succession. Importantly, most observed changes were driven by rare species. Variation was explained primarily by canopy openness at the local scale, and the tree-related microhabitat diversity and deadwood amount at landscape scales. The levels of salvage logging in our study did not explain compositional changes. We conclude that forest dieback drives changes in species assemblages that mimic natural forest succession, and markedly increases the risk of catastrophic loss of rare species through homogenization of environmental conditions

Climate-induced forest dieback drives compositional changes in insect communities that are more pronounced for rare species

Species richness, abundance and biomass of insects have recently undergone marked declines in Europe. We metabarcoded 211 Malaise-trap samples to investigate whether drought-induced forest dieback and subsequent salvage logging had an impact on ca. 3000 species of flying insects in silver fir Pyrenean forests. While forest dieback had no measurable impact on species richness, there were significant changes in community composition that were consistent with those observed during natural forest succession. Importantly, most observed changes were driven by rare species. Variation was explained primarily by canopy openness at the local scale, and the tree-related microhabitat diversity and deadwood amount at landscape scales. The levels of salvage logging in our study did not explain compositional changes. We conclude that forest dieback drives changes in species assemblages that mimic natural forest succession, and markedly increases the risk of catastrophic loss of rare species through homogenization of environmental conditions

La cartographie génétique et physique d'Arabidopsis

National audienc

Analyse des sites d'intégration de Tnt1 dans le génome d'Arabidopsis thaliana

National audienc

Le metabarcoding pour la détection et l’identification d’insectes invasifs

International audienc

Phylogeography of the ladybird Iberorhyzobius rondensis, a potential biological control agent of the invasive alien pine bast scale Matsucoccus feytaudi

Understanding the genetic structure of natural enemies is an important step to develop efficient biocontrol programs. The ladybird Iberorhyzobius rondensis Eizaguirre (Coleoptera: Coccinellidae) from the Iberian Peninsula, is a specialized predator and potential biological control of Matsucoccus feytaudi Ducasse (Hemiptera: Matsucoccidae), an invasive alien species in Southeastern France and Italy. M. feytaudi is specialized on Pinus pinaster Aiton. The beetle is also restricted to this habitat. Genetic structure of I. rondensis populations was analysed with the barcode region (COI). It revealed two main refugia areas for the beetle in Iberian Peninsula. Comparative phylogeography of the three trophic levels, plant-herbivore-predator, is discussed. Similar population structure was found for the prey and to some extent for the pine. Indications are given on where to collect the beetles for their use in biocontrol of M. feytaudi, in order to obtain the highest genetic diversity and match with the origin of the invasive prey

The rapid spread of Leptoglossus occidentalis in Europe: a bridgehead invasion

International audienceRetracing the routes of invasions and determining the origins of invading species is often critical in understanding biological invasions. The Western conifer seed bug, Leptoglossus occidentalis, an insect native of western North America, was first accidentally introduced to eastern North America and then to Europe. The colonization of the entire European continent occurred in ca. 10–15 years, probably promoted by independent introductions in different parts of Europe. A multi-marker approach (mtDNA and microsatellites) combined with approximate Bayesian computation analyses was used to track the origin of European populations and to determine whether this rapid invasion was caused by multiple introductions. Our results show that at least two independent introductions of L. occidentalis have occurred in Europe. Moreover, the analyses showed a stronger genetic similarity of European invasive populations with the eastern North American populations than with those of the native range, suggesting that invasive North American population acted as a bridgehead for European invasion. The results also revealed that natural dispersal as well as human-mediated transportations as hitchhikers probably enhanced the rapid spread of this invasive pest across Europe. This study illustrates the complexity of a rapid invasion and confirms that bridgehead and multiple introductions have serious implications for the success of invasion

Quantifying pollinator diversity along urbanization gradients in the Loire Valley

International audienc