Peng Xiaojing, Dersch Ludwig, Dresler Josephine, Lüddecke Tim, Dederichs Tim, Michalik Peter, Peigneur Steve, Tytgat Jan, Hassan Afrah, Mucciolo Antonio, Robinson-Rechavi Marc, Zancolli Giulia
Department of Ecology and Evolution, University of Lausanne, Lausanne, 1015, Switzerland.
Animal Venomics Lab, Fraunhofer Institute for Molecular Biology and Applied Ecology (IME), Ohlebergsweg 12, Gießen, 35392, Germany.
BMC Biol. 2025 Jun 13;23(1):159. doi: 10.1186/s12915-025-02248-1.
Venom, one of nature's most potent secretions, has played a crucial role in the evolutionary success of many animal groups, including spiders. However, Uloboridae spiders appear to lack venom and capture their prey, unlike venomous spiders, by extensive silk-wrapping and regurgitation of digestive fluids onto the entire prey package. A prevailing hypothesis posits that toxins may have been reallocated from the venom to alternative secretions, like silk or digestive fluids. Yet, whether uloborids have retained venom toxins and the mechanisms underlying prey immobilisation remain unresolved. Here, we employed a multi-disciplinary approach to assess the absence of venom glands in Uloborus plumipes, toxin gene expression and toxicity of digestive proteins.
Our findings confirm that U. plumipes lacks a venom apparatus, while neurotoxin-like transcripts were highly expressed in the digestive system. Midgut extract had comparable toxicity levels to that of the venomous Parasteatoda tepidariorum. However, no inhibitory effects on sodium nor potassium channels were observed, indicating a different toxic mechanism.
These findings support the hypothesis that Uloboridae spiders have lost their venom apparatus while retaining toxin-like genes. The potent toxicity of their digestive fluids, a trait conserved across spiders, likely compensate for the absence of venom, ensuring effective prey immobilisation and digestion.
毒液是自然界中最具威力的分泌物之一，在包括蜘蛛在内的许多动物群体的进化成功过程中发挥了关键作用。然而，褛网蛛科蜘蛛似乎没有毒液，与有毒蜘蛛不同，它们通过广泛地用丝包裹并将消化液反刍到整个猎物包裹上来捕获猎物。一个普遍的假说是，毒素可能已从毒液重新分配到其他分泌物中，如丝或消化液。然而，褛网蛛是否保留了毒液毒素以及猎物固定的潜在机制仍未得到解决。在这里，我们采用多学科方法来评估羽栉褛网蛛毒液腺的缺失、毒素基因表达以及消化蛋白的毒性。
我们的研究结果证实，羽栉褛网蛛没有毒液器官，而类似神经毒素的转录本在消化系统中高度表达。中肠提取物的毒性水平与有毒的温和遁蛛相当。然而，未观察到对钠通道和钾通道的抑制作用，这表明其毒性机制不同。
这些发现支持了褛网蛛科蜘蛛失去了毒液器官但保留了类似毒素基因的假说。它们消化液的强大毒性是蜘蛛共有的特征，可能弥补了毒液的缺失，确保有效地固定和消化猎物。
