Structural mouthpart interaction evolved already in the earliest lineages of insects
Structural mouthpart interaction evolved already in the earliest lineages of insects
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DOI：
10.1098/rspb.2015.1033
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发表时间：
2015-08-07
影响因子：
4.7
通讯作者：
Misof, Bernhard
中科院分区：
文献类型：
--
作者：
Blanke, Alexander;Ruehr, Peter T.;Misof, Bernhard
在蝴蝶、蜜蜂、苍蝇和真正的虫子中，特定的口器紧密接触甚至融合，以刺穿、吮吸或海绵吸取特定的食物来源。这些口器类型背后的共同现象是由几个连续的口器组成的复合体，这些口器在食物摄取过程中在结构上相互作用。因此，单个口器仅与其他相邻的口器一起起作用，这与咬咀嚼根本不同。然而，结构性口器相互作用（SMI）是何时进化的尚不清楚，因为这一原理在几个现存和灭绝的有翅昆虫群体中明显地独立地发生过多次。在这里，我们报告了一种新类型的SMI在两个最早的无翅六足动物谱系双尾目和弹尾目。我们发现，下颌骨和上颌骨相互作用，通过在上颌柄的背侧的关节螺柱，他们还支持下咽部和头囊的结构。这些相互作用是食物摄取过程中至关重要的稳定因素。SMI在这些祖先无翅昆虫中的存在，以及在那些可能是昆虫祖先的甲壳类动物中的缺失，表明SMI是昆虫的一种地平面形态。因此，我们的研究结果与目前建立的昆虫口器进化的观点相矛盾，即没有任何形式的SMI的咬咀嚼口器是祖先的配置。此外，SMI发生在最早的昆虫中，解剖学上有很大的变化。昆虫的茎组代表中的SMI可能比以前想象的更早地触发了对新的陆地食物来源的有效利用和快速适应。
In butterflies, bees, flies and true bugs specific mouthparts are in close contact or even fused to enable piercing, sucking or sponging of particular food sources. The common phenomenon behind these mouthpart types is a complex composed of several consecutive mouthparts which structurally interact during food uptake. The single mouthparts are thus only functional in conjunction with other adjacent mouthparts, which is fundamentally different to biting chewing. It is, however, unclear when structural mouthpart interaction (SMI) evolved since this principle obviously occurred multiple times independently in several extant and extinct winged insect groups. Here, we report a new type of SMI in two of the earliest wingless hexapod lineages Diplura and Collembola. We found that the mandible and maxilla interact with each other via an articulatory stud at the dorsal side of the maxillary stipes, and they are furthermore supported by structures of the hypopharynx and head capsule. These interactions are crucial stabilizing elements during food uptake. The presence of SMI in these ancestrally wingless insects, and its absence in those crustacean groups probably ancestral to insects, indicates that SMI is a groundplan apomorphy of insects. Our results thus contradict the currently established view of insect mouthpart evolution that biting chewing mouthparts without any form of SMI are the ancestral configuration. Furthermore, SMIs occur in the earliest insects in a high anatomical variety. SMIs in stemgroup representatives of insects may have triggered efficient exploitation and fast adaptation to new terrestrial food sources much earlier than previously supposed.