Apis mellifera adult workers feature more developed key brain regions than queens, which allows them to cope with the broad range of duties they need to perform in a colony. However, at the end of larval development, the brain of queens is largely more developed than that of workers. Major morphogenetic changes take place after metamorphosis that shift caste‐specific brain development. Here, we tested the hypothesis that this phenomenon is hormonally governed and involves differential gene expression. Our molecular screening approach revealed a set of differentially expressed genes in Pp (first pharate‐adult phase) brains between castes mainly coding for tissue remodelling and energy‐converting proteins (e.g. hex 70a and ATPsynβ). An in‐depth qPCR analysis of the transcriptional behaviour during pupal and pharate‐adult developmental stage in both castes and in response to artificially augmented hormone titres of 18 genes/variants revealed that: i. subtle differences in hormone titres between castes might be responsible for the differential expression of the EcR and insulin/insulin‐like signalling (IIS) pathway genes; ii. the morphogenetic activity of the IIS in brain development must be mediated by ILP‐2, iii. which together with the tum, mnb and caspase system, can constitute the molecular effectors of the caste‐specific opposing brain developmental trajectories.

中文翻译：

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蜜蜂Apis mellifera成年大脑发育差异的种姓特异性基因表达

蜜蜂成年工蚁的关键大脑区域比蜂王更发达，这使它们能够应对在群体中需要执行的广泛职责。然而，在幼虫发育末期，蚁后的大脑比工蚁的大脑更发达。主要的形态发生变化发生在改变种姓特定大脑发育的变态之后。在这里，我们测试了这种现象受激素控制并涉及差异基因表达的假设。我们的分子筛选方法揭示了种姓之间 Pp（第一阶段-成年期）大脑中的一组差异表达基因，主要编码组织重塑和能量转换蛋白（例如hex 70a和ATPsynβ）。对两种种姓的蛹和 pharate-成虫发育阶段的转录行为进行深入 qPCR 分析，并对 18 个基因/变体的人工增加的激素滴度作出反应，结果表明：i. 种姓之间激素滴度的细微差异可能是EcR和胰岛素/胰岛素样信号 (IIS) 通路基因差异表达的原因；ii. IIS 在大脑发育中的形态发生活动必须由ILP-2介导，iii。与tum、mnb和caspase系统一起，可以构成种姓特异性对立大脑发育轨迹的分子效应器。