Relatedness between colonies of origin
For each stock colony, DNA from 10 workers was extracted using a
modified Gentra PureGene protocol and genotyped at nine microsatellite
loci (Aguero et al. 2021b). Amplifications were carried out in a
volume of 10µl including 1U of HS DNA polymerase, 2µl of 5x buffer
(MyTaq™, Bioline), 0.08µl of each primer, and 1.25µl of DNA template.
PCR was performed using thermocycler T100 (Bio‐Rad). Alleles were sized
against a LIZ500 standard on an ABI 3500 genetic analyzer (Applied
Biosystems) and called using Geneious v.9.1 (Kearse et al. 2012).
Relatedness coefficients (r ) among nestmates and between workers
from each pair of colonies were estimated using the Queller and
Goodnight (Queller & Goodnight 1989) algorithm implemented in the
program COANCESTRY v.1.0 (Wang 2011). Relatedness coefficients were
weighted equally, and standard errors (SE) were obtained by jackknifing
over colonies. A principal component analysis (PCA) was performed on the
microsatellite markers using the adegenet package (Jombart 2008)
in R (R Development Core Team 2016) to visualize and confirm
genetic differentiation between sampled colonies (Figure S1).