Identifying Intraspecific Variation in Venom Yield of Chinese Cobra(Naja atra) from Ten Populations in China's Mainland

Detailed information on venom yield is helpful in preparing antivenoms and treating snakebites, but such information is lacking for many species of venomous snakes. The Chinese cobra(Naja atra) is a large sized, venomous snake commonly found in southeastern China, where it causes a heavy burden of snakebites. To examine the effects of various factors(morphology, sex, age, season, and geographical origin) on the venom yield in this snake, we collected venom samples of 446 individuals(426 adults and 20 neonates) from 10 populations of N. atra over an eightyear period. We used two variables, lyophilized venom mass(venom yield) and solid content of venom(% solids), to quantify the venom yield. We used linear regression analysis to check if venom yield was related to morphological factors, one-way ANOVA and one-way ANCOVA to detect the sexual, ontogenetic, and geographic variation in venom yield, and repeated-measures ANOVA to examine seasonal shifts in venom yield. Our results indicate that venom yield of N. atra is positively related to the morphological traits examined, with male snakes expelling more venom than females. Venom yield in N. atra was age-related, with elder snakes always expelling more venom than younger ones. Geographic variation in venom yield was also observed, while seasonal variation was not. The solid content of venom was lower in males than in females, but this was not related to morphology, season, age, or geography. Our findings suggest that venom yield in N. atra is influenced by multiple factors, as well as by the interactions among these factors.

陕北东亚钳蝎体重和性别与产毒量的相关性

为探明陕北东亚钳蝎体重和性别与产毒量的相关性,本实验采用电刺激法提取陕北野生东亚钳蝎毒液,比较了蝎子体重和性别与产毒量的关系。结果表明,蝎产毒量与体重呈正相关,体重越大的蝎子,其产毒量也越多。300~1400 mg的雌蝎,产毒量为(5.72±1.64)^(16.68±3.55)mm;300~900 mg的雄蝎,产毒量为(5.68±1.54)^(16.17±3.36)mm。500~900 mg的同体重雌雄蝎,雄蝎产毒量明显高于雌蝎,暗示雄蝎与雌蝎在运动、采食量等方面存在较大差异。该研究结果为陕北野生蝎蝎毒的功能研究奠定了一定的实验基础。

两种国产海蛇排毒量的种间差异及形态相关性

以青环海蛇(Hydrophis cyanocinctus)和平颏海蛇(Hydrophis curtus)为实验对象,探讨2种海蛇排毒量的种间差异及与形态特征的关系。研究结果显示,2种海蛇头体长(SVL)频次分布均符合正态分布且无显著性别差异,青环海蛇的SVL大于平颏海蛇。雄性青环海蛇的尾长(TL)显著大于雌性,而头长(HL)和头宽(HW)无性别差异;雌性平颏海蛇的HW显著大于雄性,而TL和HL无性别差异。2种海蛇的TL、HL和HW存在显著的种间差异。青环海蛇雌性和雄性排毒量的鲜质量、干质量和干物质含量分别为43.18 mg和33.36 mg、9.14 mg和8.05 mg、21.51%和25.01%,平颏海蛇雌性和雄性排毒量的鲜质量、干质量和干物质含量分别为33.16 mg和34.71 mg、4.40 mg和5.30 mg、13.30%和15.05%。2种海蛇排毒量的鲜质量、干质量和干物质含量无性别差异。2种海蛇的SVL、HL与排毒量鲜质量、干质量存在显著的正相关;青环海蛇HW与排毒量鲜质量存在正相关,但与干质量无显著性相关;平颏海蛇HW与排毒量鲜质量无关,但与干质量呈负相关;2种海蛇SVL、HL与干物质含量无关,但HW与干质量呈负相关。2种海蛇排毒量鲜质量、干质量和干物质含量存在显著的种间差异。本研究初步阐明了2种海蛇的排毒量特征及其形态相关性,为海蛇咬伤的临床诊疗、抗海蛇毒血清的研制及蛇毒天然活性药物的开发提供参考。