par Kratz, Fanny 
Président du jury Dahdouh-Guebas, Farid
Promoteur Vanschoenwinkel, Bram
Publication Non publié, 2023-08-31
Président du jury Dahdouh-Guebas, Farid
Promoteur Vanschoenwinkel, Bram
Publication Non publié, 2023-08-31
Mémoire
| Résumé : | Cacao (Theobroma cacao L.) is crucial for farmers in the tropics, yet uncertainty surroundsthe identity and breeding habitats of its pollinators. This study explores the flower visitingbehaviour of the main cacao flower visitors caught in a French Guiana agroforestry system,Ceratopogonidae and Cecidomyiidae, and compares their identity across Neotropical sites.DNA Barcoding was used to identify and compare specimens collected in French Guiana withour existing database of ceratopogonid sequences from Nicaragua and Peru. The results revealedthat ceratopogonids were captured throughout the day at lower temperatures thancecidomyiids on the reproductive parts of cacao flowers, illustrating potential environmentalniche differentiation. The observed flower visiting behaviour of ceratopogonids supportstheir potential role as the main suspected pollinators of cacao flowers. DNA Barcoding identifieda diverse assemblage of ceratopogonid in the French Guiana agroforestry system, withgenetic affinity to sequences from Nicaragua and Peru based on K2P and p-distances. Thesubstantial local and regional genetic diversity of flower visiting ceratopogonids in the Neotropics,suggests that the system might be relatively resilient to changes in environmentalconditions compared to a situation with a more limited set of pollinators. However, since theactivity of ceratopogonids seems to be linked to low temperatures, warming conditions, or aswitch to intensive full sun cocoa cultivation might reduce their effectiveness as pollinators.It would be important to analyse variation in pollinator communities across different cacaocultivation systems and climatic zones to get more insight in how these gradients affect pollinatorsand ultimately, yield. |
