Abstract: 【Aim】 This study aims to assess the effects of different leucine levels on the colony and worker development of Apis mellifera ligustica in breeding season. 【Methods】 Twenty-one colonies of A. mellifera ligustica in breeding season were obtained from Rongchang, Chongqing, and ranolomly divided into seven groups and fed with diets containing 0, 15.30, 17.50, 26.25, 35.00, 43.75 and 52.5 g/kg leucine, respectively. During the experiment, the colony population, amount of sealed brood, feeding amount, and queen cell building were recorded every 12 days. The foraging activity, weight of newly emerged adults, protein content and longevity of workers were detected after 24 days. 【Results】 The colony population, amount of sealed brood, feeding amount and foraging activity of the groups fed with diets containing 43.75 and 52.50 g/kg leucine were significantly higher than those of other groups (P<0.05). The protein contents in 6-day-old larvae and newly emerged workers of the control group were lower than those in the groups feeding diets containing leucine (P<0.05). The weight of newly emerged workers of the control group was significantly lower than that of the groups feeding diets containing leucine (P<0.05). There was no significant difference in the worker longevity among all groups. Building of queen cells was found in the groups fed with diets containing 26.25, 35.00 and 43.75 g/kg leucine, respectively, in 0-24 d. 【Conclusion】 Adding 43.75 and 52.50 g/kg leucine to the diet can significantly promote the development of A. mellifera ligustica colony in breeding season, and 43.75 g/kg leucine in the diet also stimulates colonies to build queen cells.  

Key words: Apis mellifera ligustica, leucine, colony, worker, nutrient requirement, queen cell building