Metabolomic profiling
The metabolome of Daphnia samples were analysed at the Natural
Environment Research Council (NERC) Biomolecular Analysis Facility at
the University of Birmingham (UK). The metabolome of Daphniasamples were analysed using nano-electrospray ionization - direct
infusion mass spectrometry (nESI-DIMS) as described by Southam et
al. (2017). The detailed methods for the nESI-DIMS was in the
supporting information. Briefly, polar metabolites were first extracted
from D. magna samples using a biphasic method. Then, all samples
were analysed in both positive and negative ionisation modes using an
Orbitrap Elite mass spectrometer (Thermo Fisher Scientific, Bremen,
Germany) with a direct infusion, chip-based nano-electrospray ionization
source (Triversa, Advion Biosciences, Ithaca, NY, USA). The data
processing was done using the Galaxy online platform using the selected
ion monitoring (SIM) stitching algorithm (Southam et al. 2017)
(see supporting information for details). The processed data matrices
were used for statistical analyses.