On springtails (Hexapoda: Collembola): phylogenetic history and morphofunctional study of the jumping apparatus

弹尾虫（六足纲：弹尾目（英语：Collembola）是一种微小的生物体，大多栖息在隐藏的地方（如深层土壤或垃圾残留物），因此对它们的形态和生物学知之甚少。尽管人们对这些动物普遍缺乏了解，但它们无处不在，显示出多种身体形态模式。它们是臭名昭著的生物体，主要是因为存在一个猫形结构，使它们能够跳跃并逃离捕食者。这种高度专门化的跳跃装置由一个可移动的结构（叉）组成，当休息时，它可以嵌入位于腹部腹侧的钩（支持带）。跳跃的动作是通过叉向身体后部的推进力发生的，这是一个机械过程的结果，涉及到一个强大的节段性肌肉组织（腹侧、背侧、背腹侧和横束）的弯曲和伸展。在跳虫中，跳跃器官的形态是相当多样的，但收敛可能会发生由于选择性压力与这些动物所占据的不同微生境，如土壤层，灌木，甚至水面。跳跃装置，包括其肌肉系统的结构变异将在弹尾目的大群体：Symphypleona，Neelipleona，Poduromorpha和Entomobryomorpha进行研究。跳跃装置和形态功能机制将被研究（叉和支持带，包括肌肉组织），也通过跳虫谱系的变化。分类群采样将被战略性地选择，允许形态和分子比较研究，允许调查弹尾目内的系统发育关系。这种形态学研究将使用新的结构研究技术μCT、cLSM和数字3D重建来开发。利用分叉和支持带的内部形态特征生成第一形态矩阵。将提供有关弹尾类的系统发育史，以及跳跃器的起源和多样化的假设。这种解释将基于使用形态学和分子数据的系统发育分析的结果。我们将研究代表跳虫跳跃器的形态多样性的类群，捕捉这些特征的物种栖息在不同的森林栖息地：深层和上层的土壤，凋落物，灌木和树冠。

Springtails (Hexapoda: Collembola) are tiny organisms mostly inhabiting hidden places (such as deeper soil layers or litter residue), thus relatively little is known about their morphology and biology. Despite the general lack of knowledge about these animals, they are everywhere, displaying a multitude of patterns of body morphology. They are notorious organisms, mainly because the presence of a catapult-shaped structure that allows them to jump and escape from predators. This highly specialized jumping apparatus consists of a movable structure (furcula) that fits into a hook (retinaculum), when in repose, located on the ventral side of abdomen. The act of jumping happens via the propulsion provided by the furcula acting towards the posterior region of the body, as a result of a mechanical process involving the flexion and extension of a strong segmental musculature (ventral, dorsal, dorsoventral and transverse bundles). Among springtails, the morphology of the jumping apparatus is quite diverse, but convergence may occur as a result of selective pressures related to the different microhabitats occupied by these animals, such as soil layer, shrubs or even the surface of the water. The structural variability of the jumping apparatus including its musculature will be studied in the large groups of Collembola: Symphypleona, Neelipleona, Poduromorpha and Entomobryomorpha. The jumping apparatus and morphofunctional mechanisms will be studied (furcula and retinaculum, including musculature), and also its variations through the lineages of Collembola. The taxon sampling will be strategically chosen allowing a morphological and molecular comparative study allowing investigation of phylogenetic relationships within Collembola. Such morphological studies will be developed using new structural research techniques μCT, cLSM and digital 3D-reconstruction. The first morphological matrix using internal morphological characters of furcula and retinaculum will be generated. Hypotheses will be provided about the phylogenetic history of Collembola, as well as on the origin and diversification of the jumping apparatus. Such interpretations will be based on the results of phylogenetic analyzes using morphological and molecular data. We will study taxa representing the morphological diversity of the jumping apparatus in Collembola, capturing these traits in species that inhabit different forest habitats: deep and upper layers of soil, litter, shrubs and canopy.