Tens of thousands of tiny painters work in John Knuth’s studio in the Echo Park neighborhood of Los Angeles. He comes in every day to feed them a mixture of sugar water and watercolor paints, and they, in turn, cover his canvases with splotches of colored vomit.
The painters are flies, and Knuth is taking advantage of a quirk of the fly digestive process that causes the insects to regurgitate their prior meal in the course of ingesting a new one. Each blotch on the canvas is a “fly speck,” a spot of water, salivary enzymes, and partially digested, sweet paint. He props canvases up vertically under netting and the flies land on them, producing a dense array of marks.
Flies regurgitate because, unlike us, they cannot chew, according to Dana Nayduch, who studies how arthropods spread pathogens at the United States Department of Agriculture’s Agricultural Research Service in Manhattan, ...
