Nano-flow liquid chromatography was performed using an Eksigent 1D nanoLC system (Dublin, CA) with direct column injection. Tips were pulled from silica capillary (75 mm I.D. 6 360 mm O.D.) in-house using a commercial CO 2 laser puller (Sutter Instruments Co., Novato, CA), and then packed to a length of 15 cm with 4 mm C12 reverse phase particles (Phenomenex, Torrance, CA). Two mL of the 1 mg/mL digested aphid protein extracts were injected directly on the column and eluted with a flow-rate of 300 nL/mn. The gradient ramped from 2% B (80:20 ACN/H 2 0) to 37% B across 50 min, and then increased to 80% B and held constant for 5 min. Initial conditions were restored for the final 15 min of the run. Electrospray ionization (ESI) was initiated by applying 2.2 kV via a liquid junction distally from the ESI tip. The capillary voltage and temperature were 42 V and 275uC, respectively. MS analyses were performed using a TSQ Vantage (ThermoFisher, San Jose, CA) operating in SRM mode. For SRM-mass spectrometry, the doubly charged precursor ions were monitored in Q1 with a resolution of 0.7 full width at half-maximum (FWHM) and three to four singly charged y-ions for each peptide were monitored in Q3 at 0.7 FWHM. Each transition was monitored for 25 ms (dwell time) enabling a maximum duty cycle of 2.5 s.