Invasive species threaten many ecological communities and predicting which communities and sites are invasible remains a key goal of invasion ecology. Although invasive ants often reach high abundances in association with plant-based carbohydrate resources, the source and provenance of these resources are rarely investigated. We characterized carbohydrate resources across ten sites with a range of yellow crazy ant abundance in Arnhem Land, Australia and New Caledonia to determine whether yellow crazy ant (Anoplolepis gracilipes) abundance and trophic position correlate with carbohydrate availability, as well as the relative importance of native and non-native sources of carbohydrates to ant diet. In both locations, measures of yellow crazy ant abundance strongly positively correlated with carbohydrate availability, particularly honeydew production, the number of tended hemipterans, and the number of plants with tended hemipterans. In Arnhem Land, 99.6% of honeydew came from native species, whereas in New Caledonia, only 0.2% of honeydew was produced by a native hemipteran. More honeydew was available in Australia due to three common large-bodied species of Auchenorrhyncha honeydew producers (treehoppers and leafhoppers). Yellow crazy ant trophic position declined with increasing yellow crazy ant abundance indicating that in greater densities the ants are obtaining more of their diet from plant-derived resources, including honeydew and extrafloral nectar. The relationships between yellow crazy ant abundance and carbohydrate availability could not be explained by any of the key environmental variables we measured at our study sites. Our results demonstrate that the positive correlation between yellow crazy ant abundance and honeydew production is not contingent upon the provenance of the hemipterans. Native sources of carbohydrate may play an underappreciated role in greatly increasing community invasibility by ants.

中文翻译：

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碳水化合物的天然和非天然来源与入侵性蚂蚁的丰度相关

入侵物种威胁着许多生态社区，预测入侵哪个社区和地点仍然是入侵生态学的主要目标。尽管与植物性碳水化合物资源相关的入侵性蚂蚁常常达到很高的丰度，但很少研究这些资源的来源和来源。我们在澳大利亚阿纳姆州和新喀里多尼亚的十个站点中使用了一系列的黄色疯狂蚂蚁来表征碳水化合物资源，以确定黄色疯狂蚂蚁（Anoplolepis gracilipes）的丰度和营养位置是否与碳水化合物的可用性相关，以及本地人的相对重要性以及蚂蚁饮食中碳水化合物的非天然来源。在这两个地方，黄色疯狂蚂蚁数量的度量值与碳水化合物的可利用性，尤其是甘露的产生，呈正相关 趋于半球的数量，以及趋于半球的植物的数量。在阿纳姆土地上，99.6％的蜜露来自本地物种，而在新喀里多尼亚，只有0.2％的蜜露是由本地的半萜产生的。由于三种常见的Auchenorrhyncha蜜露生产者（树蝉和叶蝉）的大体，澳大利亚可获得更多的蜜露。黄疯狂蚂蚁的营养位置随着黄疯狂蚂蚁丰度的增加而下降，表明在更高密度下，蚂蚁从植物来源的资源（包括甘露和花蜜）中获取更多的饮食。我们在研究地点测得的任何关键环境变量都无法解释黄色疯狂蚂蚁数量与碳水化合物供应之间的关系。我们的结果表明，黄色疯狂蚂蚁的丰度与蜜露产量之间的正相关并不取决于半翅目的起源。碳水化合物的天然来源在大大增加蚂蚁对社区的侵袭中可能起不到充分认识的作用。