Venom evolution in robber flies: An integrative approach applying functional morphology in venomics

强盗苍蝇的毒液进化：一种将功能形态应用于毒液的综合方法毒液在动物界的大多数谱系中都收敛地进化。毒液的单一蛋白质成分称为毒素，很可能只由几个蛋白质家族进化而来，这些蛋白质家族通常在每个谱系中都表现出正常的生理功能。毒液是物种进化适应性的关键资产，确保生态和进化的成功被用于防御、捕食、竞争和交流。尽管这可能对进化过程产生影响，但人们对毒液进化以及有毒类群的生物学知之甚少。此外，许多有毒种类的毒液输送系统的功能和进化尚不清楚。在经济上重要的苍蝇中，最突出的捕食性苍蝇群是Asilidae(强盗苍蝇)。据报道，自19世纪以来，强盗苍蝇就开始捕食体型更大、甚至有毒的节肢动物，这些节肢动物会立即瘫痪。这些观察结果导致了早期的假设，即强盗苍蝇在它们的毒库中使用了强烈的神经毒素。然而，直到今天，人们仍然不知道胸腺和唇腺中表达了哪些毒素以及哪种毒素表达了。我们的项目想法首次整合了基于同步加速器显微CT和静脉组学的功能形态，以更好地理解导致强盗苍蝇乃至整个昆虫如此不寻常的器官系统的进化过程。它被整合在目前的博士项目Doktorandenförderplatz Leipzig的比较毒液进化中，使用转录组学和蛋白质组学来解决特征毒素是否依赖于更多和更少特定捕食的问题。本补充形态项目的第一个目标是评估选定的知更蝇物种之间腺体形态的一般差异，这是一个新的方面，因为到目前为止还没有尝试过比较方法。此外，唇腺的焦点更强，很可能是唇腺的功能像蛇所描述的副腺一样，这是一个全新的想法。主要问题是：成对的胸腺和唇腺在形状和空间排列上在物种之间是如何变化的？特定的结构，如肌肉结构，是否促进了毒液注射的过程？毒腺系统是如何工作的？强盗苍蝇的不同生物学，特别是捕猎膜翅目昆虫的专业性，是否与腺体形态有关？我们是否发现强盗苍蝇物种的唇腺存在显著差异，如果是的话，它们是否与转录组分的结果有关？

Venom evolution in robber flies: An integrative approach applying functional morphology in venomicsVenoms have convergently evolved in most lineages of the animal kingdom. The single protein components of venoms, called toxins, likely evolved from only a few protein families that generally show normal physiological function in each lineage. Venoms are crucial assets for the evolutionary fitness of species securing ecological and evolutionary success being used for defense, predation, competition and communication. Despite the suggested impact on evolutionary processes, venom evolution, but also the biology of venomous taxa, are poorly understood. Further, the function and evolution of venom delivery systems remains unclear for many venomous taxa.Among the economically important flies, the most prominent predatory fly group is Asilidae (robber flies). Robber flies are reported since the 19th century to predate on much larger, even venomous arthropods that are paralyzed immediately. These observations led to early assumptions that robber flies utilize strong neurotoxins in their venom arsenal. However, until today it remains unknown which toxins are expressed and in which of the two thoracic and labial glands. It remains further unclear, how gland morphology varies within robber flies and if all have labial glands.Our project idea integrates for the first time functional morphology based on synchrotron micro-CT and venomics to provide a better understanding of the evolutionary processes leading to such an unusual organ system in robber flies and possibly insects in general. It is integrated in a current PhD project Comparative venom evolution of robber flies, Doktorandenförderplatz Leipzig, using transcriptomics and proteomics to address the question if characteristic toxins are depending on more and less specific predation.The first goal of the present complementary morphological project is to assess the general variation in gland morphology between selected robber fly species, which represents a new aspect since a comparative approach has not been attempted so far. Further the labial glands are in stronger focus, it could well be that labial glands function like accessory glands as described in snakes, which is a complete novel idea.Main questions are:How do the paired thoracic and labial glands vary between species regarding shape and spatial arrangement?Are specific structures like musculature facilitating the process of venom injection? How does the venom gland system work?Is a different biology of robber flies, in particular the specialization to hunt on hymenopterans, linked to gland morphology?Do we find significant differences of labial glands between the robber fly species and if so are they linked to results of the transcriptomics?