Stable isotope analysis of animal tissues is commonly used to infer diet and trophic position. However, it requires destructive sampling. The analysis of carbon isotopes from exhaled CO2 is non‐invasive and can provide useful ecological information because isotopic CO2 signatures can reflect the diet and metabolism of an animal. However, this methodology has rarely been used on invertebrates and never on social insects. Here, we first tested whether this method reflects differences in δ13C‐CO2 between workers of the Mediterranean ant Crematogaster scutellaris (Olivier) (Hymenoptera: Formicidae, Crematogastrini) fed with sugar from beet (C3; Beta vulgaris L., Amaranthaceae) or cane (C4; Saccharum officinarum L., Poaceae). We found that a significant difference can be obtained after 24 h. Consequently, we used this technique on wild co‐occurring ant species with different feeding preferences to assess their reliance on C3 or C4 sources. For this purpose, we sampled workers of C. scutellaris, the invasive garden ant Lasius neglectus (van Loon et al.) (Lasiini), and the harvester ant Messor capitatus (Latreille) (Stenammini). No significant differences in their carbon isotopic signatures were recorded, suggesting that in our study site no niche partitioning occurs based on the carbon pathway, with all species sharing similar resources. However, further analysis revealed that M. capitatus, a seed‐eating ant, can be regarded as a C3 specialist, whereas L. neglectus and C. scutellaris are generalists that rely on both C3 and C4 pathways, though with a preference for the former. Our results show that this methodology can be applied even to small animals such as ants and can provide useful information on the diets of generalist omnivores.

中文翻译：

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CO 2 碳稳定同位素分析在蚂蚁营养生态学中的应用

动物组织的稳定同位素分析通常用于推断饮食和营养位置。但是，它需要破坏性采样。从呼出的 CO2 中分析碳同位素是非侵入性的，可以提供有用的生态信息，因为同位素 CO2 特征可以反映动物的饮食和新陈代谢。然而，这种方法很少用于无脊椎动物，从未用于社会昆虫。在这里，我们首先测试了这种方法是否反映了用甜菜（C3；Beta vulgaris L.，苋科）或甘蔗（ C4；Saccharum officinarum L.，禾本科）。我们发现24小时后可以获得显着差异。最后，我们将这种技术用于具有不同摄食偏好的野生共生蚂蚁物种，以评估它们对 C3 或 C4 来源的依赖。为此，我们对 C. scutellaris、入侵花园蚂蚁 Lasius ignoreus (van Loon et al.) (Lasiini) 和收获蚁 Messorcapitaltus (Latreille) (Stenammini) 的工人进行了采样。没有记录到它们的碳同位素特征的显着差异，这表明在我们的研究地点没有基于碳途径发生生态位划分，所有物种共享相似的资源。然而，进一步的分析表明，M. capitus 是一种吃种子的蚂蚁，可以被视为 C3 专家，而 L. ignoreus 和 C. scutellaris 是依赖 C3 和 C4 途径的通才，尽管偏爱前者.