Native and non-native sources of carbohydrate correlate with abundance of an invasive ant Lori Lach 1,2 , Benjamin D. Hofmann 3 , Melinda L. Moir 2,4 1 College of Science and Engineering, James Cook University, PO Box 6811 Cairns, Queensland 4870, Aus- tralia 2 School of Biological Sciences, Te University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009, Australia 3 CSIRO, Tropical Ecosystems Research Centre, PMB 44, Winnellie, NT, 0822, Australia 4 Depart- ment of Primary Industries and Regional Development, Diagnostic Laboratory Services, 3 Baron-Hay Court, South Perth, WA 6151, Australia Corresponding author: Lori Lach (lori.lach@jcu.edu.au) Academic editor: D. Pureswaran  |  Received 24 August 2020  |  Accepted 1 December 2020  |  Published 17 December 2020 Citation: Lach L, Hofmann BD, Moir ML (2020) Native and non-native sources of carbohydrate correlate with abundance of an invasive ant. NeoBiota 63: 155–175. https://doi.org/10.3897/neobiota.63.57925 Abstract 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, par- ticularly 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 in- dicating that in greater densities the ants are obtaining more of their diet from plant-derived resources, including honeydew and extraforal nectar. Te 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. NeoBiota 63: 155–175 (2020) doi: 10.3897/neobiota.63.57925 https://neobiota.pensoft.net Copyright Lori Lach et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. RESEARCH ARTICLE Advancing research on alien species and biological invasions A peer-reviewed open-access journal NeoBiota