Tissue, ontogenic and sex-related differences in δ13C and δ15N values of the oceanic squid Todarodes filippovae (Cephalopoda: Ommastrephidae)
Tissue, ontogenic and sex-related differences in δ13C and δ15N values of the oceanic squid Todarodes filippovae (Cephalopoda: Ommastrephidae)
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DOI：
10.1007/s00227-008-1121-x
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发表时间：
2009-03-01
期刊：
影响因子：
2.4
通讯作者：
Richard, Pierre
中科院分区：
文献类型：
--
作者：
Cherel, Yves;Fontaine, Camille;Richard, Pierre
稳定同位素越来越多地被用于研究许多水生动物和最近的头足类动物的营养相互作用。为了评估该方法在鱿鱼上的应用，重要的是评估消费者组织之间和内部的同位素差异，这些差异可能会扰乱生态关系的解决。研究了2000年4月初在西南印度洋(S 44度，东经76度，圣保罗和阿姆斯特丹群岛，S 38度，东经78度)采集的55只大洋鱿鱼的组织间和组织内的同位素变异。剥离的软组织(外套膜、手臂、颊包块、鳃和生殖器官)表现出较小的Delta C-13和Delta N-15差异，可能是组织特异性的。由于脂肪去除不完全，消化腺中的碳值较低。硬组织，如喙和Gladii，N-15值低于软组织，这可以用几丁质的存在来解释，甲壳素是一种N-15缺乏的分子。女性(n=38)和男性(n=17)的Delta C-13值相同，但女性的Delta N-15值高于男性。然而，这种差异是与体型有关的，而不是与性别有关的，因为女性通常比男性更大。对体型相近的雌性和雄性进行比较，得出了相同的氮值。这些数据表明，在生长过程中，食物从较低的营养水平转变为较高的营养水平，因为大型细毛虫的增量N-15值远远高于小型标本。正如预期的那样，大型鱿鱼下喙和Gladii的氮值从最古老的区域到最新形成的区域逐渐增加，反映了几丁质化组织的渐进生长，与饮食变化平行。沿着鱿鱼喙和Gladii的生长增量进行的连续采样很可能被用来产生一个个体历史上的饮食信息的时间顺序记录。
Stable isotopes are increasingly used in the study of trophic interactions of many aquatic animals and most recently cephalopods. To evaluate the application of the method to squids, it is important to assess isotopic differences among and within consumer tissues that may confound the resolution of ecological relationships. Inter- and intra-tissue isotopic variation was examined in 55 individuals of the oceanic squid Todarodes filippovae that were collected at the beginning of April 2000 in the southwestern Indian Ocean (between 44A degrees S, 76A degrees E, and Saint Paul and Amsterdam islands, 38A degrees S, 78A degrees E). Delipidated soft tissues (mantle, arm, buccal mass, gill and reproductive organs) showed small delta C-13 and delta N-15 differences, which were probably tissue-specific. A lower carbon value was observed in the digestive gland as a consequence of incomplete lipid removal. Hard tissues, such as beaks and gladii, had lower N-15 values than soft tissues, which can be explained by the presence of chitin, a N-15-depleted molecule. Females (n = 38) and males (n = 17) had identical delta C-13 values, but females showed higher delta N-15 values than males. The difference was size-related rather than sex-related, however, as females were generally larger than males. A comparison of similar-sized females and males produced identical nitrogen values. These data suggest dietary shifts from lower to higher trophic levels during growth, because delta N-15 values of large T. filippovae were much higher than that of small specimens. As expected, nitrogen values of lower beaks and gladii of large squids increased from the oldest to the most recently formed region, reflecting the progressive growth of chitinized tissues in parallel with dietary changes. Sequential sampling along the growth increments of squid beaks and gladii can likely be used to produce a chronological record of dietary information throughout an individual's history.