Honeybees’ foraging patterns and their relation to honey antimicrobial activity

Abstract

Honeybees’ existence is highly influenced by the availability of their preferred foraging plants. This study assessed honeybees’ foraging patterns and their relationship to honey antimicrobial activity in Same District-Kilimanjaro, during the short and long rainy seasons of 2021/2022. The quadrats of 5 x 5 m (shrubs and forbs) nested with 1x1 m (grasses) were established along four transects of 5 km distance each to assess plant diversity and foraging patterns. The agar well diffusion method was employed for the antimicrobial assay. There was a significant difference in plant diversity between the rainy seasons (t = 2.60, p = 0.01 and t = 2.27, p =0.03). Grewia bicolor, Terminalia brownii, Ziziphus mucronata, Combretum schumannii, and Cordia monoica were the most visited plants by 2761, 2528, 1966, 1163, and 662 visits, during the short rain season. During the long rainy season, Acacia mellifera, Hoslundia opposita, Ocimum bacilicum, and Acalypha fruticosa were the most visited by 1638, 788, 340, and 38 visits. Honey harvested during the short rain season had higher antimicrobial activities with zones of inhibition ranging between 10 mm - 19 mm. Besides, the most susceptible microorganisms were Escherichia coli and Staphylococcus aureus. The plant leaf extracts of T. brownii, C. schumannii, and H. opposita exhibited higher antimicrobial activities against tested microorganisms. Significant differences were observed in antimicrobial activities among honey (F= 28.5, p = <0.001) and plant extracts (F= 15.9, p <0.001). A strong correlation was observed in antimicrobial activities between honey harvested during the short rainy season with T. brownii (r= 0.836, p = 0.078) and C. monoica (r = 0.732, p = 0.159). Honeybees’ foraging patterns vary among the bloomed plant species across the rainy seasons; thus, honey’s antimicrobial potential is highly influenced by floral sources and the harvesting season.