Gefen Eran, Ar Amos
Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel.
Comp Biochem Physiol A Mol Integr Physiol. 2006 May;144(1):58-62. doi: 10.1016/j.cbpa.2006.02.002. Epub 2006 Feb 14.
Scorpions of the family Buthidae have been shown to be more desiccation resistant in comparison with sympatric Scorpionidae species. This has been attributed to the surface-dwelling existence of the former, which unlike most other scorpion species do not avoid environmental extremes by burrowing. Still, within Buthidae, the mesic Buthotus judaicus showed better osmoregulatory capacities than the xeric Leiurus quinquestriatus, largely as a result of its high resistance to water loss. However, B. judaicus exhibited poor ability to regulate its haemolymph osmolarity at 37 degrees C. In this study we report a sharp increase in water loss rates of B. judaicus at the 30-35 degrees C temperature range compared to that measured for L. quinquestriatus, which could explain the poor osmoregulatory performance of the former at higher ambient temperatures. The increase in water loss rates of B. judaicus at high temperatures is not coupled with a similar increase in respiratory rate, suggesting an increase in cuticular permeability. We suggest that this increase in cuticular permeability, which may result from a relatively low critical transition temperature, contributes to limiting the distribution of B. judaicus to habitats of moderate environmental conditions.
与同域分布的蝎科物种相比，钳蝎科的蝎子表现出更强的抗干燥能力。这归因于前者的地表栖息习性，与大多数其他蝎子物种不同，它们不会通过挖掘洞穴来躲避极端环境。然而，在钳蝎科内部，生活在潮湿环境中的犹大杀牛蝎比生活在干旱环境中的五条纹肥尾蝎表现出更好的渗透调节能力，这主要是由于其对水分流失具有高度抗性。然而，犹大杀牛蝎在37摄氏度时调节其血淋巴渗透压的能力较差。在本研究中，我们报告了与五条纹肥尾蝎相比，犹大杀牛蝎在30 - 35摄氏度温度范围内的失水率急剧增加，这可以解释前者在较高环境温度下渗透调节性能较差的原因。犹大杀牛蝎在高温下失水率的增加与呼吸速率的类似增加无关，这表明其表皮通透性增加。我们认为，这种表皮通透性的增加可能是由于相对较低的临界转变温度导致的，这限制了犹大杀牛蝎分布于环境条件适中的栖息地。
