Fig. 1

Experimental design. We sampled 14 Biomphalaria alexandrina (Ba) and 14 B. glabrata (BgBS90) snails from two different tanks alternately in the morning or the afternoon. We fasted the snails overnight in trays containing water from their respective tanks. For each batch, we sampled hemolymph, then stomach, gut, hepatopancreas (liver) and ovotestis from five snails, and snap-froze two whole snails. We sampled tank and tray waters as environmental controls. We extracted DNA from each sample to prepare 16S rRNA gene libraries, and sequenced these libraries on a MiSeq platform