Inside, squirming masses of the reddish-brown insects dart between sheets of corrugated metal and egg cartons that have been tied together to provide the kind of dark hiding places they favor.
Wang Fuming kneels down and pulls out one of the nests. Unaccustomed to the light, the roaches scurry about, a few heading straight up his arm toward his short-sleeve shirt.
"Nothing to be afraid of," Wang counsels visitors who are shrinking back into the hallway, where stray cockroaches cling to a ceiling that's perilously close overhead.
Although cockroaches evoke a visceral dread for most people, Wang looks at them fondly as his fortune - and his future.
The 43-year-old businessman is the largest cockroach producer in China (and thus probably in the world), with six farms populated by an estimated 10 million cockroaches. He sells them to producers of Asian medicine and to cosmetic companies that value the insects as a cheap source of protein as well as for the cellulose-like substance on their wings.
The favored breed for this purpose is the Peripla-neta americana, or American cockroach, a reddish-brown insect that grows to about 1.6 inches long and, when mature, can fly, as opposed to the smaller, darker, wingless German cockroach.
Since Wang got into the business in 2010, the price of dried cockroaches has increased tenfold, from about $2 a pound to as much as $20, as manufacturers of traditional medicine stockpile pulverized cockroach powder.
"I thought about raising pigs, but with traditional farming, the profit margins are very low," Wang said. "With cockroaches, you can invest 20 yuan and get back 150 yuan," or $3.25 for a return of $24.
China has about 100 cockroach farms, and new ones are opening almost as fast as the prolific critters breed. But even among Chinese, the industry was little known until August, when a million cockroaches got out of a farm in neighboring Jiangsu province. The Great Escape made headlines around China and beyond, evoking biblical images of swarming locusts.
Only the prospect of all those lost earnings would faze Wang, a compact man with a wisp of a mustache and wire-rim glasses who looks like a scientist, but has no more than a high school education. After graduating, he went to work in a tire factory.
"I felt I would never get anywhere in life at the factory and I wanted to start a business," he said.
As a boy he had liked collecting insects, so he started with scorpions and beetles, both used in traditional medicine and served as a delicacy. One batch of his beetle eggs turned out to be contaminated with cockroach eggs.
"I was accidentally raising cockroaches and then I realized they were the easiest and most profitable," he said.
The start-up costs are minimal - Wang bought only eggs, a run-down abandoned chicken coop and the roofing tile. Notoriously hearty, roaches aren't susceptible to the same diseases as farm animals. As for feeding them, cockroaches are omnivores, though they favor rotten vegetables. Wang feeds his brood with potato and pumpkin peelings discarded from nearby restaurants.
Killing them is easy too: Just scoop or vacuum them out of their nests and dunk them in a big vat of boiling water. Then they're dried in the sun like chile peppers.
Perhaps understandably, the cockroach business ("special farming," as it is euphemistically called) is a fairly secretive industry. Wang's farm, for instance, operates in an agribusiness industrial park under an elevated highway. The sign at the front gate simply reads Jinan Hualu Feed Co.
Some companies that use cockroaches don't like to advertise their "secret ingredient." And the farmers themselves are wary of neighbors who might not like a cockroach farm in their backyard.
"We try to keep a low profile," said Liu Yusheng, head of the Shandong Insect Industry Association, the closest thing there is to a trade organization. "The government is tacitly allowing us to do what we do, but if there is too much attention, or if cockroach farms are going into residential areas, there could be trouble."
Liu worries about the rapid growth of an industry with too many inexperienced players and too little oversight. In 2007, a million Chinese lost $1.2 billion when a firm promoting ant farming turned out to be a Ponzi scheme and went bankrupt.
"This is not like raising regular farm animals or vegetables where the Agricultural Ministry knows who is supposed to regulate it. Nobody knows who is in charge here," he said.
The low start-up costs make raising cockroaches an appealing business for wannabe entrepreneurs, who can buy cockroach eggs and complete how-to kits from promoters.
"People laughed at me when I started, but I always thought that cockroaches would bring me wealth," said Zou Hui, 40, who quit her job at a knitting factory in 2008 after seeing a television program about raising cockroaches.
It's not exactly a fortune, but the $10,000 she brings in annually selling cockroaches is decent money for her hometown in rural Sichuan province, and won her an award last year from local government as an "Expert in Getting Wealthy."
"Now I'm teaching four other families," Zou said. "They want to get rich like me."
But inexperienced farmers can get into trouble, as Wang Pengsheng (no relation to fellow roach farmer Wang) found out after his cockroaches staged the Great Escape.
He had opened his farm just six months earlier in a newly constructed building that municipal code officials complained was too close to protected watershed land. At noon on Aug. 20, while workers were out for lunch, a demolition crew knocked down the building. The roaches made a run for it.
"They didn't know I had cockroaches in there. They wouldn't have demolished the building like that if there were cockroaches that would get out," Wang Pengsheng said in a telephone interview.
After discovering the flattened building and homeless roaches scurrying among the rubble, he tried to corral the escapees but was unsuccessful. He called in local health officials, who helped him exterminate the roaches. Wang said he has received about $8,000 in compensation from local government and hopes to use the money to rebuild his farm elsewhere.
At least five pharmaceutical companies are using cockroaches for traditional Chinese medicine. Research is underway in China (and South Korea) on the use of pulverized cockroaches for treating baldness, AIDS and cancer and as a vitamin supplement. South Korea's Jeonnam Province Agricultural Research Institute and China's Dali University College of Pharmacy have published papers on the anti-carcinogenic properties of the cockroach.
Li Shunan, a 78-year-old professor of traditional medicine from the southwestern province of Yunnan who is considered the godfather of cockroach research, said he discovered in the 1960s that ethnic minorities near the Vietnamese border were using a cockroach paste to treat bone tuberculosis.
"Cockroaches are survivors," Li said. "We want to know what makes them so strong - why they can even resist nuclear effects."
Li reels off an impressive, if implausible, list of health claims: "I lost my hair years ago. I made a spray of cockroaches, applied it on my scalp and it grew back. I've used it as a facial mask and people say I haven't changed at all over the years.
"Cockroaches are very tasty too."
Many farmers are hoping to boost demand by promoting cockroaches in fish and animal feed and as a delicacy for humans.
Chinese aren't quite as squeamish as most Westerners about insects - after all, people here still keep crickets as pets.
In Jinan, Wang Fuming and his wife, who run the farm together, seem genuinely fond of their cockroaches and a little hurt that others don't feel affection.
"What is disgusting about them?" Li Wanrong, Wang's wife, asked as a roach scurried around her black leather pumps. "Look how beautiful they are. So shiny!"
Over lunch at a restaurant down the block from his farm, Wang placed a plate of fried cockroaches seasoned with salt on the table along with more conventional cuisine, and proceeded to nibble a few with his chopsticks. He expressed disapproval that visiting journalists refused to sample the roaches.
On saying goodbye at the end of the day, he added a final rejoinder.
"You will regret your whole life not trying them."
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