*Appendix A.2. Methods*

Mosquitoes were reared within the insectaries of LITE at the Liverpool School of Tropical Medicine at 26 ± 2 ◦C and 80 ± 10% relative humidity. A cohort of approximately 100 2–5 day old female *Anopheles gambiae* (Kisumu) were starved in a standard (30 × 30 × 30 cm) BugDorm-1 (MegaView Science Co., Ltd., Taichung, Taiwan) cage for approximately 18 h with ad libitum access to purified (Merck Millipore, Darmstadt, Germany) water-soaked cotton placed on the ceiling mesh of the cage, but with sugar feeders removed. Just before testing began, 20 mosquitoes were sampled at random, knocked down by CO2 gas exposure, weighed, and then frozen. The remainder in the cage were then offered a sugar meal in pots of 10% sugar-soaked cotton with 0.8% Uranine covered in a double-layer of netting to prevent tarsal contact.

Mosquitoes were observed directly for a period of 3 h. Feeding behavior was defined as a mosquito landing on the feeder, probing, and subsequently positioning the proboscis down through the mesh and remaining still while the abdomen was observed to visibly expand, filling with some amount of the dyed sugar solution. Individuals seen to engage in feeding behavior were removed and frozen immediately after feeding ended to prevent or slow any digestive processes that could affect the fluorescence levels of the ingested sugar solution. 38 mosquitoes were observed to feed within the time period and collected in this fashion. Fed mosquitoes were then homogenized in 10 mL purified water, 2 mL of which was decanted into plastic cuvettes and read in a TrilogyTM Fluorometer (model 7200-0000, Turner Designs, San Jose, CA, USA) to give raw fluorescence units (RFU) of each solution. This was compared to a calibration curve generated using serial dilutions of the same stock of 0.8% Uranine and 10% sugar solution (Figure A1) to give the concentration of each homogenized sample. From this, the volume of sugar solution ingested by each mosquito was calculated using a simple concentration calculation (C1V1 = C2V2). Four of the twenty mosquitoes removed previously for weighing were randomly selected and were treated in the same way to control for autofluorescence or contamination.
