One morning in Denver as artist John Knuth was getting his exhibition ready at the David B Smith Gallery, the police knocked on the door to check he wasn’t housing a dead body. “They said, ‘We’ve got a report of a lot of flies in here. Is there a dead body or anything rotting?’” Knuth recalls to the Guardian over Zoom.

The hundreds of flies emerging from Knuth’s gallery were actually his collaborators. For over a decade, Knuth has been creating paintings using the regurgitation of tens of thousands of flies. “When flies eat they digest externally,” explains Knuth. “They’re in a constant state of regurgitation. They land on a surface, puke up, suck it back in. Puke up, suck it back in.” After feeding the insects a mixture of acrylic colored paint and sugar water, the flies spend several weeks expelling the mixtures on to his canvases. “From that I get these really transcendent color connections.”

While that might sound like a rather odd and disgusting approach, Knuth has been praised for pushing the boundaries of nature, beauty and process with his abstract pointillist paintings, which have been described as “vibrant and seemingly luminescent” and “incandescent [and] shimmering”.

As well as being sticky work, it occasionally leads to run-ins with the law. After inviting the investigating Denver police officers inside the gallery, the effortlessly effervescent and excitable Knuth charmingly explained that rather than concealing a corpse, the flies were busy at work. “I told them, ‘I’m an artist. Hundreds of thousands of flies are making paintings for me. Some are escaping.” The cops quickly echoed the usual response Knuth gets for his work from critics and gallery visitors alike. “They were so intrigued. They were like, ‘This is amazing.’ They invited the people at the bank who reported the flies over and 20 minutes later they were all on board with it and apologizing for raising a fuss.”

Knuth is currently showcasing his latest array of fly paintings at the Hollis Taggart gallery in New York as part of his exhibition, The Hot Garden. This showcase has been particularly resonant for Knuth. It’s his first major exhibition since he lost the Los Angeles home he shared with his wife and child, as well as his entire archive, in January’s Eaton fire. After the tragedy, Knuth returned to fly paintings as “they helped pay for my house that burned down. I wanted to get back to the beginning point.”

It was almost inevitable that Knuth’s art would intersect with nature. Growing up in the suburbs of Minneapolis and St Paul, Knuth spent all of his time catching snakes, frogs, turtles, and fishing. Knuth’s fascination with animals and insects continued when he became an artist. He would mix rattlesnake venom with paint, he painted coyote penis bones gold, and created gold leaf horseshoe crabs. Even he recognizes that he’s chosen quite an unusual path. “I remember thinking at one point, ‘What the fuck am I doing? Why didn’t I start painting nudes or get a muse?’”

While struggling in high school, Knuth found his salvation in several art books at the library. Intrigued by the work of Andy Warhol and Jasper Johns in particular, Knuth started to regularly visit the variety of art museums across Minneapolis. “There’s a tremendous art community there that fed my curiosity. That’s really where I discovered art.” Knuth then attended the University Of Minnesota, where he got a BFA in art, and worked under Mark Dion – a conceptual artist renowned for mixing art and science. “He was my mentor. He showed me you can be really smart and an intellectual troublemaker, plus go out and drink beer and make a living as an international artist.”

Knuth was first struck by the idea to work with flies in the buildup to the 2003 Iraq war. After reading that flies had been responsible for more human suffering than all wars, because of how they have spread malaria and numerous other diseases, Knuth initially wanted to create an anti-war piece by tying paper airplanes on to house flies to make his “own little biological warfare air force”. As he explored this option, he noticed that flyspeck looked like little spots of paint.

In 2005, Knuth continued his experimentation by feeding flies McDonald’s and Taco Bell. But the results were just brown paintings. “They were cool conceptual objects. But not beautiful artworks.” He also didn’t have enough money to buy the number of flies he required to fulfill his vision. Then in 2013, Knuth was approached by the Museum Of Contemporary Art in Los Angeles to do a “big production” of his fly paintings. The resulting video went viral. “That moment made my career. Since then I’ve had shows around the world.” Knuth’s fly paintings have been bought by multiple private art collectors and are also in the permanent collection at the Asheville Art Museum, North Carolina.

The Hollis Taggart show marks Knuth’s third solo exhibition in New York. After being approached by director Paul Efstathiou in February, Knuth devised the concept of the Hot Garden because he wanted to reflect what he and numerous artists had gone through with the Los Angeles fires. “This was a generation changing event for my generation of artists. I literally know hundreds of artists that got hit by this. Five artists on my block alone lost their houses.” Since his work had always engaged with climate, bugs and life, it felt like a natural continuation to bring the fire into his paintings. For the titular piece of the exhibition, Knuth wanted to create “distorted or distressed landscapes by pulling paint across the canvas to make fire motifs”. For the piece January 7, the day that Knuth watched his home burn down, he mixed red, lavender and green flyspeck to produce a “dark and ominous” tone and visuals reminiscent of fire and smoke. While constructing his paintings, Knuth looked at Monet’s use of color compositions in his lily paintings, while turning to warm colors, like oranges and yellows, because they represented heat.

Knuth isn’t just presenting his fly paintings at The Hot Garden. He’s also exhibiting a sculptural installation, entitled The Sculpture Garden. It includes fragments of artworks recovered from his destroyed home, as well as pieces from other artists affected by the fire. Glenn Phillips, the director of the Getty Research Center, was so impressed that he’s already bought two pieces for the Getty Museum. Including, This Is Our Pompeii, a New York Times article on the impact of the LA fires on local artists, covered in red flyspeck.

While Knuth is delighted that the fly paintings have connected with art lovers and critics yet again, he can’t help but get a little somber when asked if the exhibition has helped him process his trauma. “Being busy helps. Having a reason to keep doing this helps. But all of my archive and retrospective is gone. That’s the first 25 years of my career. My work was a way to engage in the world. Unfortunately the world engaged with me pretty intensely six months ago. There’s just so much tragedy in the world that the news cycle moves on.”

But as Knuth picks up the pieces for the next phase of his career, he’s not straying too far away from the formula that has garnered him so much success. His new Pasadena studio is full of dead flies caught in fly traps hanging from the globe, giant fishhook sculptures, dead stuffed rattlesnakes painted red, and hundreds of black sea urchins in gold foil painted black. “I’m 46 now, so hopefully I have another 25 years left to make up for what I lost.”