Fig. 1
From: Nitrogen fixation by diverse diazotrophic communities can support population growth of arboreal ants
Visual appearance of patch types maintained by Azteca ants and quantified N2 fixation activity. a An initial patch (IP), here inside a cross-sectioned internode, is built up by a foundress queen scratching off parenchyma. Patch material of established b A. alfari and c A. constructor colonies (established patches (EP)) is consisting of plant material, dead nestmates, fungi, and nematodes. Patch samples and parenchyma from the inner walls of uninhabited plant internodes were incubated for 72 h in an artificial 15N2:O2 atmosphere. d The 15N atom percent excess (APE) [%] depicted on the y-axis shows significant N2 fixation in patches, but not in the plant parenchyma (Pa). e The amount of fixed N per mg sample (dry weight) depicted on the y-axis shows variations, but insignificant differences between Azteca species (alf, A. alfari; con, A. constructor; xan, A. xanthochroa) within patch types (IP, EP). Sample sizes are given in brackets, and significant differences are indicated by asterisks (***P < 0.001). Scale bars, 1 cm (a–c)