Investigation on flowering characteristics and diversity of flower-visiting insects for loquat in the Yuanjiang River dry-hot valley

Loquat is an important economic crop of Yuanyang County, where is in the dry-hot valley of the Yuanjiang River. In order to systematically evaluate the species and pollination performance of loquat flower-visiting insects and explore the possibility of using bees as pollinators to improve the fruit quality and production efficiency, this study investigates the blooming and nectar secretion patterns of loquat, as well as the diversity of flower-visiting insects in the region. In the large-scale loquat planting area in Nansha Town, Yuanyang County, we examined the floral structure, flowering period, nectar secretion patterns, diversity of pollinating insects, and flower-visiting behavior of the dominant species. The results showed that the nectar secretion volume of individual loquat flowers varied significantly among five time points throughout the day: 9:00, 11:00, 13:00, 15:00, and 17:00, with respective averages of (12.42 ± 1.05) μL, (12.75 ± 0.85) μL, (9.24 ± 0.82) μL, (5.25 ± 0.62) μL, and (4.81 ± 0.63) μL, showing a gradual decreased over time. The nectar concentration at these five time points also showed significant differences, with values of (23.33 ± 1.53) %, (24.31 ± 1.01) %, (28.07 ± 2.91) %, (36.90 ± 3.99) %, and (30.25 ± 5.53) %, respectively, following a pattern of first increasing and then decreasing, peaking at 15:00. This study identified four species of insects visiting loquat flowers. Among them, Apis cerana cerana had a dominance index of 0.8533, which was the dominant species; its flower visitation frequency was (4.00 ± 0.65) flowers/min and an average stay time was (10.03 ± 0.50) per flower. Introducing A. cerana cerana colonies for loquat pollination, number of honey bees leaving the hive, returning to the hive, and carrying pollen showed a significant correlation with the nectar volume and nectar concentration of individual loquat flowers, but not with temperature, humidity or illumination. The peak period of visiting flowers occurred later than that of leaving the hive. As the dominant visiting insect during the flowering period of loquat, the introduction of artificially reared A. cerana cerana colonies in orchards during the flowering period can effectively increase the number of visiting insects, facilitate loquat pollination, and provide pollination services for large-scale planting of loquat.