Hertz Eric, Trudel Marc, Cox Marlin K, Mazumder Asit
Department of Biology University of Victoria PO BOX 3020 Station CSC Victoria BC Canada V8W 3N5.
Department of Biology University of Victoria PO BOX 3020 Station CSC Victoria BC Canada V8W 3N5 ; Pacific Biological Station Department of Fisheries and Oceans Canada 3190 Hammond Bay Road Nanaimo BC Canada V9T 6N7.
Ecol Evol. 2015 Oct 8;5(21):4829-39. doi: 10.1002/ece3.1738. eCollection 2015 Nov.
Many organisms experience fasting in their life time, and this physiological process has the potential to alter stable isotope values of organisms, and confound interpretation of food web studies. However, previous studies on the effects of fasting and starvation on stable isotopes show disparate results, and have never been quantitatively synthesized. We performed a laboratory experiment and meta-analysis to determine how stable isotopes of δ (15)N and δ (13)C change with fasting, and we tested whether moderators such as taxa and tissue explain residual variation. We collected literature data from a wide variety of taxa and tissues. We surveyed over 2000 papers, and of these, 26 met our selection criteria, resulting in 51 data points for δ (15)N, and 43 data points for δ (13)C. We determine that fasting causes an average increase in the isotopic value of organisms of 0.5‰ for δ (15)N and that the only significant moderator is tissue type. We find that the overall effect size for δ (13)C is not significant, but when the significant moderator of tissue is considered, significant increases in blood and whole organisms are seen with fasting. Our results show that across tissues and taxa, the nutritional status of an organism must be considered when interpreting stable isotope data, as fasting can cause large differences in stable isotope values that would be otherwise attributed to other factors.
许多生物体在其生命周期中会经历禁食，这种生理过程有可能改变生物体的稳定同位素值，并混淆食物网研究的解释。然而，先前关于禁食和饥饿对稳定同位素影响的研究结果各不相同，且从未进行过定量综合分析。我们进行了一项实验室实验和荟萃分析，以确定δ（15）N和δ（13）C的稳定同位素如何随禁食而变化，并测试了诸如分类群和组织等调节因素是否能解释剩余变异。我们从各种各样的分类群和组织中收集了文献数据。我们查阅了2000多篇论文，其中26篇符合我们的选择标准，得出δ（15）N的51个数据点和δ（13）C的43个数据点。我们确定禁食会使生物体的δ（15）N同位素值平均增加0.5‰，唯一显著的调节因素是组织类型。我们发现δ（13）C的总体效应大小不显著，但考虑到组织这一显著调节因素时，禁食会使血液和整个生物体中的δ（13）C显著增加。我们的结果表明，在不同组织和分类群中，解释稳定同位素数据时必须考虑生物体的营养状况，因为禁食会导致稳定同位素值出现很大差异，而这些差异否则会归因于其他因素。
