Fig. 1

Blood preferentially enters the midguts during blood-sucking mode. (A) Photograph of the artificial membrane feeding system (top left) and an enlarged view of the feeder cup in which the meal solution is heated with circulating warm water and the bottom is covered with stretched parafilm (top right). Mosquitoes land on the membrane (bottom left) and pierce it to feed, and perforations can be seen in the stretched membrane (yellow arrowheads, bottom right). (B) Diagram showing how meal destination patterns were scored (left) and percent of mosquitoes showing “meal in midgut only” (light blue) and “meal in crop (and midgut)” (light orange) when tested under the indicated feeding conditions. Numbers of fed mosquitoes for each condition are indicated to the right of the graph. Unless otherwise specified, RT = 28 °C. (C) Photographs of dissected guts showing imbibed solutions in the crop and midgut scored from 0 (none) to 3 (highest). The scores are color coded as follows: 0 = blue, 1 = orange, 2 = gray, and 3 = yellow. (D) Pie charts showing fractions of mosquitoes scored as in C for feeding conditions indicated on the left. Total numbers of mosquitoes for each feeding condition are noted on the right. (E) Distribution scores (see STAR METHODS) for results shown in D.