Data from: Can social partnerships influence the microbiome? insights from ant farmers and their trophobiont mutualists.

Mutualistic interactions with microbes have played a crucial role in the
evolution and ecology of animal hosts. However, it is unclear what factors
are most important in influencing particular host-microbe associations.
While closely related animal species may have more similar microbiota than
distantly related ones due to phylogenetic contingencies, social
partnerships with other organisms, such as those in which one animal farms
another, may also influence an organism’s symbiotic microbiome. We studied
a mutualistic network of Brachymyrmex and Lasius ants farming several
honeydew-producing Prociphilus aphids and Rhizoecus mealybugs to test
whether the mutualistic microbiomes of these interacting insects are
primarily correlated with their phylogeny or with their shared social
partnerships. Our results confirm a phylogenetic signal in the microbiomes
of aphid and mealybug trophobionts, with each species harboring
species-specific endosymbiont strains of Buchnera (aphids), Tremblaya and
Sodalis (mealybugs), and Serratia (both mealybugs and aphids) despite
being farmed by the same ants. This is likely explained by strict vertical
transmission of trophobiont endosymbionts between generations. In
contrast, the ants’ microbiome is potentially shaped by their social
partnerships, with ants that farm the same trophobionts also sharing
strains of sugar-processing Acetobacteraceae bacteria, known from other
honeydew-feeding ants and which likely reside extracellularly in the ants’
guts. These ant-microbe associations are arguably more ‘open’ and subject
to horizontal transmission or social transmission within ant colonies.
These findings suggest that the role of social partnerships in shaping a
host’s symbiotic microbiome can be variable, and is likely dependent on
how the microbes are transmitted across generations.