A few days ago, while walking in the woods, I allowed a mosquito to suck blood from my hand for about 20 seconds. Holding my arm extended like a sweaty middle-aged messiah, I watched as the insect tapped methodically at my skin, watched as it pushed its needle nose into the flesh between my smallest knuckles, watched as its hitherto-imperceptible belly bulged and turned a shiny, jubilant red.