The role of gland secretions from brood bees and of larval nutrion in caste determination in eusocial stingless bees and bumble bees

该项目的一个主要目标是确定化合物，介导种姓特定的发展在幼虫的原始真社会性熊蜂（熊蜂terrestris）和高度真社会性无刺蜂（Schwarziana quadripunctata）。我们将调查是否香叶醇（或化学上类似的化合物）从唇腺分泌的护士蜜蜂作为引物信息素触发女王的发展，我们最近发现在另一个无刺蜂（Melipona beecheii）。研究种姓决定的比较方法，包括人工饲养的真社会蜜蜂，其中幼虫直接由护士喂养（熊蜂），在大量供应的大或正常大小的育雏室中产生常规和小型蜂王的高度真社会性蜜蜂（Schwarziana）和高度真社会性的蜜蜂，仅从正常大小的育雏细胞产生蜂王（Melipona）将揭示真社会性蜜蜂中种姓决定机制的进化。本项目的第二个目标是确定香叶醇介导M. beecheii。我们将测试我们的假设，萜烯香叶醇作为一个必不可少的前体分子的合成萜类保幼激素，这是产生大量的幼虫发育成皇后。用氘标记的香叶醇喂养幼虫进行生物测定，将显示它们是否合成氘标记的保幼激素。最后，从植物衍生的幼虫食物的挥发物的分析将揭示是否种姓决定化合物包含在花粉或花蜜，蜜蜂幼虫的祖先食物。这些研究将为真社会性蜜蜂中决定种姓的化合物的进化起源提供结论。

A main goal of the project is the identification of compounds that mediate caste specific development in larvae of a primitvely eusocial bumble bee (Bombus terrestris) and a highly eusocial stingless bee (Schwarziana quadripunctata). We will investigate whether geraniol (or chemically similar compounds) from labial gland secretions of nurse bees acts as primer pheromone triggering queen development, as we recently found in another stingless bee (Melipona beecheii). The comparative approach to investigate caste determination including primitively eusocial bees, in which larvae are directly fed by nurse workers (Bombus), highly eusocial bees that produce regular and miniature queens in mass provisioned large or normal sized brood cells (Schwarziana) and highly eusocial bees that solely produce queens from normal sized brood cells (Melipona) will shed light on the evolution of caste determining mechanisms in eusocial bees. The second goal of the project is the identification of the proximate mechanism, by which geraniol mediates queen development in M. beecheii. We will test our hypothesis that the terpene geraniol serves as an essential precursor molecule for the synthesis of the terpenoid juvenile hormone, which is produced in high amounts in larvae developing into queens. Bioassays with deuterium-labelled geraniol fed to larvae will show whether they synthesize deuterium-labelled juvenile hormone. Finally, analyses of volatiles from plant derived larval food will reveal whether caste determining compounds are contained in pollen or nectar, the ancestral food for bee larvae. These investigations will allow providing conclusion for the evolutionary origins of caste determining compounds in eusocial bees.