Karowe David N
Department of Biology, University of Michigan, 48109, Ann Arbor, MI, USA.
Oecologia. 1989 Sep;80(4):507-512. doi: 10.1007/BF00380074.
Feeding efficiencies of ultimate instar larvae of two polyphagous tree-feeding Lepidoptera, Malacosoma disstria (Lasiocampidae) and Orgyia leucostigma (Liparidae), were measured on artificial diets containing from 0% to 8% tannic acid. Relative growth rate (RGR) of O. leucostigma was not affected by up to 8% tannic acid, suggesting that O. leucostigma has evolved an effective counteradaptation to hydrolyzable tannins. In contrast, as little as 0.5% tannic acid caused a significant reduction in RGR of M. disstria, due both to reduced efficiency of conversion of digested food (ECD) and reduced relative consumption rate (RCR), and caused a significant increase in mortality during the pupal stage. Moreover, when reared from hatching on tannin-containing diets, no M. disstria larvae survived past the fourth instar.Although tannins are commonly referred to as "digestibility-reducing substances", tannic acid did not reduce the ability of M. disstria or O. leucostigma larvae to digest either the whole diet or nitrogen contained in the diet. For M. disstria, tannic acid acts as a toxin and a feeding deterrent, but not as a digestibility-reducing substance. Growing evidence that tannins commonly act as toxins warrants a reassessment of their role in anti-herbivore chemistry.
在含有0%至8%单宁酸的人工饲料上，对两种多食性食叶鳞翅目昆虫——天幕毛虫（枯叶蛾科）和白纹毒蛾（毒蛾科）末龄幼虫的取食效率进行了测定。高达8%的单宁酸对白纹毒蛾的相对生长率（RGR）没有影响，这表明白纹毒蛾已经进化出了对可水解单宁的有效适应性反应。相比之下，低至0.5%的单宁酸就会导致天幕毛虫的RGR显著降低，这是由于消化食物的转化效率（ECD）降低和相对摄食率（RCR）降低所致，并且导致蛹期死亡率显著增加。此外，当天幕毛虫幼虫从孵化开始就在含单宁的饲料上饲养时，没有幼虫能存活到四龄以后。尽管单宁通常被称为“降低消化率的物质”，但单宁酸并没有降低天幕毛虫或白纹毒蛾幼虫消化整个饲料或饲料中所含氮的能力。对于天幕毛虫来说，单宁酸起到了毒素和摄食威慑剂的作用，但不是降低消化率的物质。越来越多的证据表明单宁通常起到毒素的作用，这就需要重新评估它们在抗食草动物化学中的作用。
