Fig. 4

Estimation of volume of ATP solution ingested by mosquitoes using the naked eye. a Classification of mosquitoes that sucked green-colored 0.1 mM ATP solution. Class 1A (diamond), fully engorged abdomen; class 1B (circle), partially swollen abdomen; class 2 (triangle), colored abdomen with intact shape; and class 3 (square), abdomen with intact shape and no color observed. White vertical lines on each image indicate the thicknesses of abdomens. b A scatter plot indicates a linear relationship between the two variables, absorbance at 638 nm of the mosquito extract and the thicknesses of mosquito abdomens. Simple linear regression analysis was performed using data of class 1A and 1B mosquitoes (R² = 0.9325)