BACKGROUND
This study examined whether honey bees prefer certain pollen substitute diets and whether the distance of a supplemental food source from the apiary affects foraging. The authors focused on *Apis mellifera jemenitica* in Saudi Arabia, where high summer temperatures, floral scarcity, and dry conditions can reduce pollen availability and colony performance. Because pollen is the main source of protein and other essential nutrients for brood production, immunity, and colony maintenance, beekeepers often use substitute diets during dearth periods. The authors compared four flour-based substitutes—chickpea, maize, sorghum, and wheat—prepared in different combinations with cinnamon powder, turmeric powder, both powders, or flour only, against natural bee pollen as a control. They also tested whether bees preferred the best-performing diets when placed at 10, 25, and 50 m from the hives.
METHODS
The study was conducted at the Unit of Bee Research and Honey Production, King Khalid University, Abha, Saudi Arabia, using local honey bee colonies housed in Langstroth hives. Colonies were clinically healthy and managed according to routine recommendations. Experimental diets were prepared from the four flours, with naturally collected pollen used as the control. The text states that each diet was tested with three replications for five pollen substitute diets, including naturally collected pollen as a control on diet preference, although the full treatment coding system included multiple flour-spice combinations. Diets were offered externally in powdered form. Bee visitation was visually counted, and diet consumption was calculated by weighing feed before and after feeding. For the distance-choice experiment, the best-performing diets (CPCM, CPTM, CPOY, CPBH, and PNOY) were offered on separate plates at 10, 25, and 50 m from the apiary. Honey bee numbers were counted at 7–8 A.M., 11–12 A.M., and 4–5 P.M., with three visual counts per interval. Statistical analysis used analysis of variance, means ± standard error, and Tukey post hoc comparisons at the 0.05 level.
KEY RESULTS
Across the full observation period, the highest visitation was to natural pollen (PNOY), with 210 ± 25.96 visits, followed closely by chickpea flour only (CPOY), with 205 ± 19.32. The lowest visitation was to MZOY and SGOY, each with 2.33 ± 1.45 and 2.33 ± 0.88, followed by WTOY with 2.66 ± 2.18. In week 1, maximum visitation was observed on PNOY with 143 ± 12.89/week, followed by CPOY with 133.67 ± 13.75/week and CPBH with 78 ± 38.07/week. The fewest visits were on MZOY with 1.33 ± 0.88/week, followed by SGOY and WTOY with 2 ± 0.57/week and 2 ± 1.52/week. In week 2, CPOY had 71.66 ± 6.06/week and PNOY had 67 ± 13.11/week, while SGOY had 0.33 ± 0.33/week, WTOY had 0.66 ± 0.66/week, and MZOY had 1 ± 0.57/week. Overall variability in visitation among diets was significant, with F (16,34) = 17.91; *p* < 0.01.
Diet consumption paralleled visitation. In week 1, the highest consumption was for PNOY at 404 ± 28.15 g/week, followed by CPOY at 350 ± 8.21 g/week and CPBH at 235.67 ± 7.85/week. The least consumption was WTOY at 5 ± 4.04 g/week, followed by MZOY at 7.66 ± 4.97 g/week and SGOY at 11 ± 2 g/week. In week 2, the highest consumption was CPTM at 203.33 ± 16.41 g/week, followed by CPBH at 192 ± 6.42 g/week and PNOY at 172 ± 38.15 g/week. Across the whole study, the greatest total consumption was again PNOY at 576 ± 58.85 g, followed by CPOY at 463.33 ± 42.84 g, CPBH at 427.67 ± 6.35 g, and CPTM at 384.67 ± 14.72 g. The least consumption was WTOY at 7 ± 6.02 g, followed by MZCM at 16 ± 8.32 and MTTM at 63 ± 21.37. Differences in diet consumption were significant overall, with F (16,34) = 29.75; *p* < 0.01.
The association between visitation and consumption was strong. Pearson’s correlation was 0.957 during the first week, 0.89 during the second week, and 0.94 for the total observation period.
Foraging effort in relation to distance showed a clear preference for closer food sources. At 7–8 A.M. and 10 m, visitation was highest on PNOY at 282.5 ± 2.5, followed by CPOY at 277.5 ± 7.5, whereas CPCM had 75 ± 5 and CPBH had 79.5 ± 0.5. At 25 m, PNOY had 145.5 ± 3 and CPOY had 252.5 ± 2.5, while CPTM had 50 ± 5 and CPBH had 51 ± 1. At 50 m, PNOY had 237 ± 7 and CPOY had 215.5 ± 14.5, while CPCM had 34.5 ± 4.5 and CPBH had 37.5 ± 2.5. At 11–12 A.M. and 10 m, PNOY had 226 ± 1 and CPOY had 220.5 ± 0.5; at 25 m, CPOY had 202.5 ± 6.5 and PNOY had 202 ± 3; at 50 m, CPOY had 180 ± 10 and PNOY had 176 ± 1. At 4–5 P.M. and 10 m, PNOY had 205 ± 10 and CPOY had 178 ± 7; at 25 m, PNOY had 185 ± 10 and CPOY had 164 ± 6; at 50 m, PNOY had 145 ± 9 and CPOY had 140 ± 10. The interaction between time of day, distance, and diet type was non-significant: F (16,45) = 1.017 (*p* = 0.458). However, time of day and distance interacted significantly: F (16,45) = 3.063 (*p* = 0.026), as did time of day and diet type: F (16,45) = 33.349 (*p* = 0.001).
CLINICAL IMPLICATIONS
Although this is not a clinical study, it has practical implications for apiculture. Natural pollen remained the preferred food, but chickpea flour only was the strongest-performing substitute, both in visitation and consumption. The findings suggest that during periods of pollen scarcity, chickpea flour may be the most acceptable substitute among those tested, and supplemental diets should ideally be placed very near the hive, particularly at 10 m, to maximize foraging activity and feed uptake. The authors emphasize that further research is needed to determine how these diets affect colony health, physiology, and productivity over time.