科学网Biology of spiders : metabolism 02 毒腺和毒性(3)

(a)   Dorsal view of the spitting spider Scytodes; note the feeble legs and the massive prosoma with distinct markings (Photo: Erb) (b) Longitudinal section of the prosoma of Scytodes. The enormous venom glands consist of an anterior portion that produces venom and a posterior part that synthesizes a gluey substance. Rapid contraction of the prosomal muscles squirts out a mixture of venom and glue from the chelicerae. CNS = central nervous system. (After Millot, 1949.)

图3.5(A)吐出的蜘蛛Scydes的背面图；注意虚弱的腿和有明显斑点的巨大头胸甲(Photo: Erb)(B)Scydes头胸部的纵切面。巨大的毒腺由产生毒液的前部和合成胶状物质的后部组成。前体肌肉的快速收缩会从螯肢中喷出一种毒液和胶水的混合物。CNS=中枢神经系统。(After Millot, 1949.)

Figure 3.6

(a, b) Spitting pattern of a Scytodes with the typical zigzag pattern of the capture threads. (Photos: Suter.)

Scytodes的吐痰图案：捕获线的典型之字形图案(Photos: Suter.)。

The prime example of a spider dangerous to humans is certainly the black widow spider, Latrodectus mactans, from the family  Theridiidae  (fig.  3.7a,  b). The bite itself is not particularly painful and often is not even noticed (Maretic, 1983, 1987). The first real pain is felt after 10–60 minutes in the regions of the lymph nodes, from where it spreads to the muscles. Strong muscle cramps develop, and the abdominal muscles become very rigid (this is an important diagnostic feature). Another typical symptom is a contorted facial expression, called facies latro- dectismi, which refers to a flushed, sweat-covered face, swollen eyelids, inflamed lips, and contracted masseter muscles. If the breathing muscles of the thorax become affected, this can eventually lead to death. Besides the strong muscle pain, the black widow spider venom (BWSV) also elicits psychological symptoms, which range from anxiety feelings to actual fear of death. Apparently the toxin can pass the blood-–brain barrier and directly attack the central nervous system.

蜘蛛对人类危害最大的例子当然是来自球蛛科的黑寡妇蜘蛛Latrodectus mactans (fig.3.7a，b)。咬伤本身并不特别痛，通常甚至没有人注意到(Maretic，1983,1987)。第一次真正的疼痛是在10-60分钟后在淋巴结区域感受到的，从那里扩散到肌肉。出现强烈的肌肉痉挛，腹部肌肉变得非常僵硬(这是一个重要的诊断特征)。另一个典型的症状是扭曲的面部表情，称为facies latrodectismi，指的是面部红肿、汗水覆盖的脸、眼睑肿胀和咀嚼肌收缩。如果胸部的呼吸肌受到影响，最终可能会导致死亡。除了强烈的肌肉疼痛，黑寡妇蜘蛛毒液(BWSV)还会引起从焦虑到实际恐惧死亡的心理症状。显然，这种毒素可以通过血脑屏障，直接攻击中枢神经系统。

Figure 3.7

Dangerous poisonous spiders. (a) A Black Widow (Latrodectus) from South America, dorsal aspect. The black abdomen has contrasting white and red chevron markings.

(a)   A North American black widow (Latrodectus mactans) with the typical (red) hourglass mark on the ventral side of the abdomen. (c) Portrait of a brown recluse spider (Loxosceles); note the six eyes and the droplet of venom hanging between the chelicerae (arrow). (d) Portrait of the ctenid Phoneutria fera, a rather aggressive spider from South America. (Photos b–d: Rast.)