Dynafor présent à la 13ième édition du congrès ECE 2026

Mélodie Ollivier a présenté un poster intitulé "Comparison of several biological matrices for studying wild bee diversity using metabarcoding" lors du 13ieme congrès européen d’entomologie (ECE 2026) qui a eu lieu au Palais des Congrès Vinci de Tours du 29 juin au 3 juillet 2026. Plusieurs dynaforiens à savoir Anaïs Marquisseau, Jérôme Willm, Mélodie Ollivier et Magalie Pichon sont co-auteurs de ce poster, avec des collègues de l'unité Genphyse d'INRAE de Toulouse et des experts entomologistes indépendants qui porte sur les travaux obtenus dans le cadre du projet de recherche BEETRACK co-coordonné par Mélodie Ollivier et Magalie Pichon et financé par l'OFB sur l'appel d'offre ECOPHYTO II. Ce poster a été illustré par des dessins naturalistes réalisés par François Calatayud membre de l'unité Dynafor lui-aussi et doué en dessin.

Marquisseau, A. ; Klopp, C.; Canale-Tabet, K.; Labarthe, E.; Simon, E.; Rudelle, R. Willm, J. ; Castinel, A.; Ollivier, M.; Pichon M. (2026) Comparison of several biological matrices for studying wild bee diversity using metabarcoding. XIII European Congress of Entomology, June 29 to July 3, Centre de Congrès Vinci, Tours (France).

Abstract:

DNA metabarcoding is a molecular method that can be used to effectively study and monitor pollinator communities on a large scale. However, conventional molecular approaches, which involve partial or total destruction of specimens, have several limitations: loss of rare individuals, inability to re-extract DNA in case of sequencing failure, or the need for additional morphological examination when molecular identification fails (incomplete databases, poorly discriminating markers, or contamination). To circumvent these problems, we compared the resolution of metabarcoding from bee tissues with that of an approach using trapping and storage liquids.

Seventeen plots in the Zone Atelier Pyrénées Garonne (ZA PYGAR, Haute-Garonne) were equipped with colored bowls filled with water and detergent for three days. The captured bees were stored in ethanol at -20°C, as were the trapping liquids. After morphological identification by an expert, a leg from each specimen was taken for tissue metabarcoding, while DNA was also extracted from the storage liquids. COI and 16S markers were used for amplification and sequencing.

For the 16S marker, the results show that 27% of species could not be identified molecularly due to incomplete databases at the time of analysis. Furthermore, 67% of species identified morphologically were detected by conventional metabarcoding, compared to only half with liquids (trapping or storage). However, the latter reveal a greater diversity of insects, suggesting preferential amplification of groups other than wild bees by the marker used.