Ledesma Matias, Gorokhova Elena, Holmstrand Henry, Garbaras Andrius, Karlson Agnes M L
Department of Ecology Environment and Plant Science (DEEP) Stockholm University Stockholm Sweden.
Department of Environmental Science and Analytical Chemistry (ACES) Stockholm University Stockholm Sweden.
Ecol Evol. 2020 Sep 23;10(19):10773-10784. doi: 10.1002/ece3.6734. eCollection 2020 Oct.
According to ecological theory, two species cannot occupy the same niche. Using nitrogen isotope analyses (δN) of amino acids, we tested the extent to which two sympatric deposit-feeding amphipods, and , partition their trophic resources. We found that trophic position (TP) and resynthesis index (∑V; a proxy for degradation status of ingested material prior to assimilation by the consumer) differ between species. The surface-feeding had higher TP and intermediate ∑V, both pointing to a large contribution of metazoans in its diet. , which feeds in the subsurface layers, had lower TP and a bimodal distribution of the ∑V values, supporting previous experimental evidence of a larger feeding niche. We also evaluated whether TP and ∑V values have consequences for amphipod fecundity and embryo viability and found that embryo viability in was negatively linked to TP. Our results indicate that the amino acid-δN data paired with information about reproductive status are useful for detecting differences in the trophic ecology of sympatric amphipods.
根据生态理论，两个物种不能占据相同的生态位。我们利用氨基酸的氮同位素分析（δN），测试了两种同域分布的沉积取食性双壳类动物在划分其营养资源方面的程度。我们发现，物种之间的营养级位置（TP）和再合成指数（∑V；消费者同化之前摄入物质降解状态的一个替代指标）存在差异。表层取食的[物种名称1]具有较高的TP和中等的∑V，这两者都表明后生动物在其饮食中占很大比例。在表层以下取食的[物种名称2]，TP较低且∑V值呈双峰分布，这支持了之前关于更广泛取食生态位的实验证据。我们还评估了TP和∑V值是否对双壳类动物的繁殖力和胚胎活力有影响，发现[物种名称2]的胚胎活力与TP呈负相关。我们的结果表明，氨基酸δN数据与繁殖状态信息相结合，对于检测同域双壳类动物营养生态学的差异是有用的。
