Community composition of psylliphagous ladybirds in a tropical island environment in La Réunion island, France

Baujeu Marine, Moquet Laura, Chiroleu Frédéric, Reynaud Bernard. 2023. Community composition of psylliphagous ladybirds in a tropical island environment in La Réunion island, France. In : ECE 2023 - Books of abstracts. Heraklion : Hellenic Entomogical Society, Résumé, 145. European Congress of Entomology. XII, Heraklion, Grèce, 16 Septembre 2023/20 Septembre 2023.

Résumé : Predatory ladybirds have long been used in biological control. These species often share the same prey and are therefore organised in communities. In Reunion Island, located in the south-west of the Indian Ocean, three quarters of the 26 species present have been introduced for biological control. Since 2006, Réunion has been invaded by a psyllid originating from Australia: Acizzia uncatoides, which is spreading and impacting an endemic tree: Acacia heterophylla. In order to evaluate the relevance of a biological control programme against this psyllid, we studied the psylliphagous ladybird communities in Réunion. A regular sampling of 11 sites was carried out between 2020 and 2021. At each site, 10 trees hosting psyllid colonies were sampled with Garden Vaccum for one minute and then visually examined to estimate the abundance and richness of psyllids and ladybirds. Fifteen species of ladybirds were identified at the adult stage and five at the larval stage. The larvae of three species feed on psyllids. The first and the most abundant, Exochomus laeviusculus, is a species with a generalist diet, is positively influenced by the psyllids' abundance and negatively by the landscape's diversity. The second, Olla vnigrum, is a psylliphagous species voluntarily introduced in Reunion in 1990. Its abundance is positively influenced by meteorological variables such as the average monthly temperature. The last, C.septempunctata, is a species known for its aphidiphagous diet. Introduced since 2020 in Réunion, its presence could be due to the scarcity of its prey which would incite them to consume the psyllids.

Mots-clés libres : Community ecology, Biological Control, Ladybird, Psyllids

Auteurs et affiliations

• Baujeu Marine, CIRAD-BIOS-UMR PVBMT (REU)
• Moquet Laura, CIRAD-BIOS-UMR PVBMT (REU) ORCID: 0000-0001-7873-2218
• Chiroleu Frédéric, CIRAD-BIOS-UMR PVBMT (REU) ORCID: 0000-0002-4874-5357
• Reynaud Bernard, Université de la Réunion (REU)

Source : Cirad-Agritrop (https://agritrop.cirad.fr/606979/)

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