Sanger sequencing is potentially a cost-effective and relatively rapid way to detect the most abundant plant prey in the diets of invasive fire ants. This is especially valuable as observational techniques to infer diet are not always parsimonious and may contain bias. In this study we introduce a novel way of analyzing plant diet of Solenopsis invicta workers using universal ITS2 primers for gene amplification and Sanger sequences to match sequence reads to plant species.
Results/Conclusions
Primers successfully amplified plant DNA (267 & 280 bp fragments) from the whole bodies of worker ants sampled from longleaf pine savannas. Of the 96 samples sequenced, the most frequent matches were Lolium spp. (grass), which are unlikely to inhabit our sites. Approximately 28 samples did not have matches within the reference database (GenBank), possibly owing to the low taxonomic resolution of our small amplicons or digestive damage to plant DNA. Sanger sequencing likely detected the most abundant plant food, as indicated by titration experiments of DNA extracted from two plant species -- Gaylussacia frondosa and Vaccinium tenellum. The data presented in this study will help advance the knowledge of fire ant food webs and how colonies are able to successfully invade biodiverse habitats.