Heterogeneous metabolite secretion by O. unilateralis s.l. on four ant species’ brains. (A) Venn-diagram comparing all ion features found to be significantly (P < 0.01) enriched in the medium of samples in which O.unilateralis s.l. was grown next to ex vivo kept ant brains of the species C. castaneus, C. americanus, C. pennsylvanicus and F. dolosa. (B) Bar chart visualizing how the ions, that were found to be significantly enriched (P < 0.01) due to O. unilateralis s.l.-C. castaneus brain interactions across two independent studies, overlap with ions enriched in interactions with other species’ brains.