Sun Yan-Yan, Yang Jing, Ji Xiang
Hangzhou Key Laboratory for Animal Sciences and Technology, School of Life Sciences, Hangzhou Normal University, Hangzhou 310036, Zhejiang, China.
J Exp Zool A Ecol Genet Physiol. 2009 Feb 1;311(2):125-33. doi: 10.1002/jez.509.
We used the many-lined sun skink (Mabuya multifasciata) as a model system to evaluate the energetic and locomotor costs of tail loss, and to examine whether tailless skinks compensate for the costs of tail loss by increasing feeding rate or digestive efficiency. We successively removed three tail segments from each of the 20 experimental skinks initially having intact tails. Energy content in each removed tail segment was measured, and swimming performance was measured for each experimental skink before and after each tail-removing treatment. Another independent sample of 19 skinks with intact tails were measured for swimming performance to serve as controls for successive measurements taken for the experimental skinks. Tailless experimental skinks and control skinks were then measured for food intake and digestive efficiency. Tail loss affected swimming speed, but the adverse influence was not significant until more than 55% of the tail (in length) was lost. Our data show that partial tail loss may not severely affect energy stores or locomotor performance in M. multifasciata. However, as tail breaks occurred more frequently in the proximal portion of the tail in skinks collected from the field, we conclude that caudal autotomy occurring in nature often incurs substantial energetic and locomotor costs. As tailless and tailed skinks did not differ in food intake, apparent digestive coefficient and assimilation efficiency, we conclude that tailless individuals do not compensate for the costs of tail loss by increasing feeding rate or digestive efficiency in M. multifasciata.
我们以多线日守宫(Mabuya multifasciata)作为模型系统,来评估断尾所带来的能量消耗和运动成本,并研究无尾守宫是否会通过提高摄食率或消化效率来弥补断尾的成本。我们从最初尾巴完整的20只实验守宫身上依次切除三段尾巴。测量每段切除尾巴的能量含量,并在每次断尾处理前后测量每只实验守宫的游泳表现。另外选取19只尾巴完整的守宫作为独立样本测量其游泳表现,作为对实验守宫连续测量的对照。然后测量无尾实验守宫和对照守宫的食物摄入量和消化效率。断尾会影响游泳速度,但直到尾巴(长度)损失超过55%,这种负面影响才显著。我们的数据表明,部分断尾可能不会严重影响多线日守宫的能量储备或运动表现。然而,由于从野外采集的守宫尾巴近端更频繁地出现断裂,我们得出结论,自然界中发生的尾部自切往往会带来巨大的能量和运动成本。由于无尾和有尾守宫在食物摄入量、表观消化系数和同化效率上没有差异,我们得出结论,在多线日守宫中,无尾个体不会通过提高摄食率或消化效率来弥补断尾的成本。