Gene Chou (MS 2009) investigated how nitrogen isotopic data can be used to study assimilation of plant-based resources by ant colonies. In a greenhouse-based, diet-manipulation experiment, we reared Argentine ant colonies with and without honeydew-producing aphids but fed all colonies insects. Workers from colonies without aphids had N15 values that were, on average, 6.31% larger compared to those from colonies with aphids. These data thus illustrate how isotopic data can clarify whether ants assimilate plant-based resources. The monopolization of such resources (especially honeydew produced by Hemiptera) is linked to invasion success.
Menke, SB, AV Suarez, CV Tillberg, CT Chou and DA Holway. 2010. Trophic ecology of the invasive Argentine ant: spatio-temporal variation in resource assimilation. Oecologia. 164:763-773.