Insect visitors of green fruits of Annona senegalensis Pers. (Annonaceae) and their potential role in the plant fruiting

Abstract

Annona senegalensis is a multipurpose wild shrub mainly used for food and traditional medicine by local people in tropical African. During its fruiting period, especially at the green fruit stage, this plant harbors an important community of insects such as various ant species (Formicidae) and the planthopper Hilda undata Walker (Tettigometridae). This study aimed at understanding the role of ants on Annona senegalensis during the fruiting period. Insect visitors of green fruits of Annona senegalensis were collected randomly on 30 green fruits from 30 plants per site, at four sites across the Sudanian and Sudano-Sahelian climatic zones of Burkina Faso, from June to July 2020. The behavior of insects was observed in the field. HPLC analyses of sugar profiles of the extrafloral nectar of green fruits, ants and Hilda undata were carried out in the laboratory to determine whether ants were feeding on green fruit nectar and Hilda undata honeydew. Ants were the most recorded visiting insect group, representing up to 95% of the insects observed on the fruit and the most frequently encountered species were Trichomyrmex abyssinicus Forel, Crematogaster sp., Messor galla Mayr, Brachyponera sennaarensis Mayr and the planthopper Hilda undata. Coleoptera, Diptera, Hemiptera, Hymenoptera and Lepidoptera were recorded. Behavioural observations and HPLC analyses showed that ants consumed extrafloral nectar of green fruits and the Hilda undata honeydew. Ants protect the green fruits and Hilda undata from pests. This study is the first report highlighting mutualistic interactions between Annona senegalensis, ants and Hilda undata.