Effectiveness of wild bees in the pollination of Citrullus lanatus l. in the Algerian Sahara

This study was carried out at an experimental site in Laghrousse, province of Biskra (Algeria), on a Watermelon crop (Citrullus lanatus L.) during the 2024 flowering period. Among the inspected insect groups, Hemiptera and Coleoptera are considered as visitors; Hymenoptera, Diptera, and Lepidoptera are considered as pollinators of watermelon. The statistical analysis showed that Hymenoptera is the most abundant group and the main pollinators in this crop. It was found that seven species of wild bees- Halictus rubicundus (Christ, 1791), Lasioglossum pallens (Brullé, 1832), Lasioglossum sisymbrii (Cockerell, 1895) (Hymenoptera: Halictidae), Hylaeus hyalinatus (Smith, 1842) (Hymenoptera: Colletidae), Megachile rotundata (Fabricius, 1787) (Hymenoptera: Megachilidae), Epeolus cruciger (Panzer, 1799), and Anthophora bimaculata (Panzer, 1798) (Hymenoptera: Apidae) were their most effective pollinators, although watermelon is a self-compatible plant. The intervention of pollinators in this culture by xenogamy improves the quantitative yield of the watermelon by a percentage of 94,27% and qualitatively by increasing the market value of the fruits by a percentage of 100%, compared to self-pollination by geitonogamy. The study also identified five species of wild flowering plants: Reseda lutea L. (Resedaceae); Convolvulus cantabrica L. (Convolvulaceae); Carduus nigrescens Vill. (Asteraceae); Sinapis pubescens L. (Brassicaceae); and Torilis arvensis (Huds.) Link. (Apiaceae), at the edges of the greenhouse, which attract these wild bee species pollinating watermelons.