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ABSTRACT We investigate the spectroscopic properties of 85 brightest cluster galaxies (BCGs) and their companions observed with the SDSS MaNGA integral field unit. Galaxy redshifts are between 0.08 < z < 0.15, allowing for a field-of-view up to 80 × 80 kpc. For the main galaxies: the average age of the BCG cores is 7.66$$\, \pm \,$$1.36 Gyr with no significant gradient out to $$2\, R_ {e}$$; the average metallicity of the BCG cores is $$[Z/H]=0.23\, \pm \, 0.03$$ with a negative gradient of Δ[Z/H]/Δ(R/Re)  = –0.14$$\, \pm \, 0.09$$ which flattens beyond $$1.2\, R_ {e}$$. Velocity dispersion gradients are mostly flat, but a few positive slopes are seen in the most massive galaxies. Emission lines are present in 12 of the BCGs, most often confined to the central $$\sim 2\,$$ kpc with emission line ratios well-described by a LINER or AGN excitation source. There are 78 companion galaxies identified and 9 have nebular emission lines that indicate recent star formation. The companions with flux ratios of 4:1 and 20:1 within 30 kpc of their BCG’s core are studied. The companion galaxies have a median age of 7.65$$\, \pm \,$$1.55 Gyr and are high-metallicity systems, with a median [Z/H] = 0.17  ±  0.07. Close spectroscopic companions with higher merging probabilities have an average merging time of 0.5 ± 0.2 Gyr. The average merger rate is 0.08$$\, \pm \, 0.12 \,$$ Gyr−1 for 4:1 companions and 0.26$$\, \pm \, 0.22 \,$$ Gyr−1 for 20:1 companions, allowing for an increase in mass of 2.3$$\, \pm \,$$3.4 per cent Gyr−1 and 3.5$$\, \pm \,$$3.2 per cent Gyr−1, respectively. 

ABSTRACT Priority effects, where the order and timing of species arrival influence the assembly of ecological communities, have been observed in a variety of taxa and habitats. However, the genetic and molecular basis of priority effects remains unclear, hindering a better understanding of when priority effects will be strong. We sought to gain such an understanding for the nectar yeastMetschnikowia reukaufiicommonly found in the nectar of our study plant, the hummingbird‐pollinatedDiplacus(Mimulus)aurantiacus. In this plant,M.reukaufiican experience strong priority effects when it reaches flowers after other nectar yeasts, such asM.rancensis. After inoculation into two contrasting types of synthetic nectar simulating early arrival ofM.rancensis, we conducted whole‐transcriptome sequencing of 108 strains ofM.reukaufii. We found that several genes were differentially expressed inM.reukaufiistrains when the nectar had been conditioned by growth ofM.rancensis. Many of these genes were associated with amino acid metabolism, suggesting thatM.reukaufiistrains responded molecularly to the reduction in amino acid availability caused byM.rancensis. Furthermore, investigation of expression quantitative trait loci (eQTLs) revealed that genes involved in amino acid transport and resistance to antifungal compounds were enriched in some genetic variants ofM.reukaufii. We also found that gene expression was associated with population growth rate, particularly when amino acids were limited. These results suggest that intraspecific genetic variation in the ability of nectar yeasts to respond to nutrient limitation and direct fungal competition underpins priority effects in this microbial system.