Exploiting an extraordinary case of intrasexual cuticular hydrocarbon profile dimorphism in a mason wasp, Odynerus spinipes, to shed new light on cuticular hydrocarbon genetics and evolution

昆虫的角质层被一层角质层碳氢化合物（CHCs）所覆盖。CHCs作为一种重要的干燥屏障，在昆虫间的交流中具有重要的基础作用。例如，在许多物种中，chc作为物种和性别识别的线索和信号。然而，人们对CHCs生物合成过程中涉及的基因知之甚少。特别是在种类丰富的昆虫目膜翅目中，包括蚂蚁、蜜蜂和黄蜂，这些基因就是这种情况。在一项由dgf资助的研究项目中，我们最近发现了一种独特的无性内CHC二态性的特殊情况：雌性泥瓦蜂Odynerus spinipes能够表达两种非常不同的CHC化学型。这两种化学型在70多种物质上有质的不同。在同一时间和采样地点发现的不同化学型的棘棘棘猴雌性在任何非CHC相关性状上都没有差异，这使得该物种成为了解更多CHC生物合成相关基因的合适和有希望的模型。因此，我们的研究项目旨在确定那些基因参与了令人震惊的CHC二态性在O. spinipes的表现。为了鉴定具有化学型相关活性/表达差异的基因，我们将对转录本进行测序，并评估转录本的丰度，以衡量每种化学型的棘棘棘成年雌性所有蛋白质编码基因的相应基因的活性。为了证明这些基因的表达与CHCs的生物合成之间的因果关系，我们打算通过实验操纵10个选定的基因的表达，这些基因的表达在不同化学型的雌性中存在显著差异。我们将通过一种称为RNA干扰（RNAi）的分子技术来操纵上述基因的表达。我们计划的实验是可行的，因为我们能够在实验控制的条件下培养O. spinipes，并且已经对O. spinipes基因组进行了深度测序。我们将比较这些候选基因的核苷酸和氨基酸序列，这些候选基因参与了CHC的生物合成，我们能够通过实验证明，与另外21种寄生蜂的相应序列进行比较，我们在国际1KITE项目（http://www.1kite.org）中对其转录本进行了测序。这也将使我们能够阐明这些基因的进化史以及对它们起作用的选择力。伴随的实验室和野外实验将解决成年棘棘棘蛛雌性是否能够改变其化学型的问题。因此，我们项目的结果将成为许多生物学科研究人员的主要和基本兴趣，从化学生态学和进化基因组学到物种形成遗传学和行为生物学。

The cuticle of insects is covered by a layer of cuticular hydrocarbons (CHCs). CHCs serve as an important desiccation barrier and have gained additional fundamental importance for communication among insects. For example, in many species, CHCs act as cues and signals for species and sex recognition. However, little is known about the genes involved in the biosynthesis of CHCs. In particular this is the case for these genes in the species-rich insect order Hymenoptera, which includes ants, bees, and wasps. In context of a DGF-funded research project, we recently discovered an extraordinary case of distinct intrasexual CHC dimorphism: females of the mason wasp Odynerus spinipes are capable of expressing two very different CHC chemotypes. These two chemotypes differ qualitatively from each other in over 70 substances. O. spinipes females with different chemotypes found at the same time and at the sample place do not differ in any non CHC-related trait, making this species an eligible and promising model for learning more about the genes involved in CHC biosynthesis. Our research project accordingly aims to identify those genes that are involved in the manifestation of the astounding CHC dimorphism in O. spinipes. To identify genes with chemotype-associated activity/expression differences, we will sequence the transcripts, and assess the transcripts' abundance as a measure of the activity of the corresponding genes, of all protein-coding genes of adult O. spinipes females of each chemotype. To demonstrate a causal link between the expression of these genes and the biosynthesis of CHCs, we intend to experimentally manipulate the expression of ten selected genes, whose expression significantly differs between females with different chemotype. We will manipulate the expression of the above genes by means of a molecular technique called RNA interference (RNAi). Our intended experiments are feasible, since we are able to raise O. spinipes under experimentally controlled conditions and have deeply sequenced the O. spinipes genome. We will compare the nucleotide and amino acid sequences of those candidate genes, whose involvement in CHC biosynthesis we were able to experimentally prove, with corresponding sequences from 21 additional vespid wasps, whose transcripts we sequenced in the international 1KITE project (http://www.1kite.org). This will allow us to also shed light on the evolutionary history of these genes and on the selective forces that have acted on them. Accompanying laboratory and field experiments will address the question of whether or not adult O. spinipes females are capable of changing their chemotype. The results from our project will consequently be of major and fundamental interest to researchers in numerous biological disciplines, ranging from chemical ecology and evolutionary genomics to speciation genetics and behavioral biology.