【目的】 本文旨在探究意大利蜜蜂Apis mellifera ligustica幼虫饲粮中添加叶酸对雌性蜜蜂DNA甲基化及发育的影响。【方法】 从姊妹蜂群中选用2日龄意大利蜜蜂雌性幼虫，平均分为6组，任选一组以饲喂不添加叶酸的基础日粮为对照组（CK），其余5组为试验组，分别饲喂添加0.02%、0.04%、0.06%、0.08%和0.10%叶酸的基础日粮。在室内温度（34.5 ± 0.5）℃，相对湿度为90% ± 5%的条件下，按照饲养流程饲养意大利蜜蜂至出房。取3-5日龄的幼虫，测定叶酸代谢指标及DNA甲基化相关指标，计算新蜂发育历期，称量新蜂重。【结果】 （1）添加叶酸（FA）水平为0.04%的试验组，3、4和5日龄幼虫蜂体内叶酸（FA）和5-甲基四氢叶酸（5-MTHF）含量显著高于对照组（P ˂ 0.05），并且显著提高了幼虫时期蜂体的二氢叶酸还原酶（DHFR）基因、丝氨酸羟甲基转移酶（SHMT）基因和亚甲基四氢叶酸还原酶（MTHFR）基因的表达量（P ˂ 0.05），显著提高了MTHFR酶活性（P ˂ 0.05）。（2）与对照组相比，添加叶酸为0.04%的试验组显著提高了3日龄幼虫DNA甲基转移酶1a（Dnmt1a）基因的表达量（P ˂ 0.05），且显著提高了3日龄和4日龄幼虫的DNA甲基转移酶1（DNMT1）酶活性（P ˂ 0.05）。添加0.04%的叶酸试验组相较于对照组显著降低了3日龄幼虫DNA甲基转移酶3（DNMT3）的酶活性（P ˂ 0.05），显著降低了4日龄幼虫Dnmt3基因的表达量和DNMT3酶活性（P ˂ 0.05）。叶酸添加剂量为0.04%时，4日龄蜂体DNA甲基化水平显著降低（P ˂ 0.05）。（3）与对照组相比，添加0.04%的叶酸试验组的意大利蜜蜂平均发育历期（19.95 d）显著小于对照组（P ˂ 0.05），平均新蜂重（0.17 g）显著大于对照组（P ˂ 0.05）。【结论】 在基础日粮中添加适量叶酸能够降低4日龄意大利蜜蜂幼虫的DNA甲基化水平，并能缩短发育历期和增加新蜂重。在饲粮中添加0.04%的叶酸有助于雌性意大利蜜蜂幼虫向蜂王方向发育。

[Objectives]  To investigate the effect of adding folic acid to the larval diet of Apis mellifera ligustica on DNA methylation and female development. [Methods]  Two-day-old female A. m. ligustica larvae were randomly selected from sister colonies and divided into six equal-sized groups. The control group (CK) was fed a diet without additional folic acid, whereas the remaining five groups were fed the same diet with the addition of either 0.02%, 0.04%, 0.06%, 0.08% or 0.10% folic acid. Larvae were reared at room temperature of (34.5 ± 0.5) ℃ at a relative humidity of 90% ± 5% until they emerged. Indices of folic acid metabolism and DNA methylation related indices were measured in 3- to 5-day-old larvae, and the developmental duration and weight of newly emerged bees was recorded. [Results]  (1) The 0.04% treatment group had significantly higher levels of folic acid (FA) and 5-methyltetrahydrofolate (5-MTHF) than the control group at 3, 4 and 5 days of age (P < 0.05). This group also had significantly higher expression of the dihydrofolate reductase (DHFR) gene, the serine hydroxymethyltransferase (SHMT) gene and the methylenetetrahydrofolate reductase (MTHFR) gene (P < 0.05), and significantly higher MTHFR enzyme activity (P < 0.05), in the larval period. (2) This treatment group also had significantly higher expression of the DNA methyltransferase 1a (Dnmt1a) gene in 3-day-old larvae (P < 0.05), and significantly higher DNA methyltransferase 1 (DNMT1) enzyme activity in 3- and 4-day-old larvae, than the control group (P < 0.05). The 0.04% treatment group had significantly lower DNA methyltransferase 3 (DNMT3) enzyme activity in 3-day-old larvae compared to the control group (P < 0.05), and significantly lower Dnmt3 gene expression and DNMT3 enzyme activity in 4-day-old larvae (P < 0.05). The level of DNA methylation in this treatment group was also significantly lower in 4-day-old bees (P < 0.05). (3) The average developmental duration (19.95 d) of the 0.04% treatment group was significantly lower (P < 0.05), and the average weight (0.17 g) of newly emerged bees was, significantly higher, than that of the control group (P < 0.05). [Conclusion]  The addition of 0.04% folic acid to the larval diet can reduce DNA methylation in 4-day-old A. m. ligustica larvae, shorten developmental duration and increase the weight of newly emerged bees. The addition of 0.04% folic acid to the larval diet helps female A. m. ligustica larvae develop into Queens.