Supporting data for "Metabarcoding versus mapping unassembled shotgun reads for identification of prey consumed by arthropod epigeal predators"

A central challenge of DNA gut content analysis is to identify prey in a highly degraded DNA community. In this study, we evaluated prey detection using metabarcoding and a method of mapping unassembled shotgun reads (Lazaro). <br>In a control mock prey community, metabarcoding did not detect any prey, probably due to primer choice and or preferential predator DNA amplification, while Lazaro detected prey with accuracy 43-71%. Gut content analysis of field-collected arthropod epigeal predators (three ants, one dermapteran and one carabidae) from agricultural habitats in Brazil (27 samples, 46-237 individuals per sample) revealed that 64%of the prey species detections by either method were not confirmed by Melting Curve Analysis and 87% of the true prey were detected in common. We hypothesized that Lazaro would detect fewer true and false positive and more false negative prey with greater taxonomic resolution than metabarcoding, but found that the methods were similar in these respects and had similar accuracy (metabarcoding: 64%; Lazaro: 67%). While metabarcoding detected 350x more true prey reads than Lazaro, this did not convert into a higher number of true positive prey detections. There was a positive correlation between the relative prey DNA concentration in the samples and the number of prey reads detected by Lazaro, while this was inconsistent for metabarcoding. <br>Metabarcoding and Lazaro had similar, but partially complementary, detection of prey in arthropod predator guts. However, while Lazaro was almost 2x more expensive, the number of reads was related to the amount of prey DNA, suggesting that Lazaro can provide quantitative prey information while metabarcoding may not.