Rarefaction curves of the three sample types. The individual samples of the same type were pooled and resampled 10,000 times to determine the number of OTUs found with different numbers of sequencing reads. The error bars indicate ± one standard deviation. (A) P. schultei anterior midgut (Ps_AMG) samples. (B) R. artemis anterior midgut (Ra_AMG) samples. (C) R. artemis posterior midgut (Ra_PMG) samples.