SHANGHAI — Li Xin knelt in a hotel room here, wearing polka-dot boxer shorts and a grimace on his face.
The deputy mayor of Jining, in Shandong province, was pleading with his lover not to report him to authorities.
But in the end, the 51-year-old official was exposed and sentenced to life in prison. His crime: accepting more than $500,000 in bribes, which he used to support at least four mistresses in Jining, Shanghai and Shenzhen.
Li's transgressions were minor compared with those of other public officials. A top prosecutor in Henan province, for example, was recently stripped of his post and Communist Party membership after investigators alleged that he embezzled $2 million to support his lavish lifestyle -- and seven mistresses.
"Everyone is saying, 'Behind every corrupt official, there must be at least one mistress,' " says Li Xinde, an anti-corruption activist who researched Li Xin's case and posted on his website a photo of the deputy mayor begging in the hotel room.
China's economic boom has led to a revival of the 2-millennium-old tradition of "golden canaries," so called because, like the showcase birds, mistresses here are often pampered, housed in love nests and taken out at the pleasure of their "masters."
Concubines were status symbols in imperial China. After the Communists took power, they sought to root out such bourgeois evils, even as Chairman Mao Tse-tung reportedly kept a harem of peasant women into his old age.
Now, mistresses have become a must-have for party officials, bureaucrats and businessmen.
"We are in a commodity economy," says retired Shanghai University sociologist Liu Dalin. "Work, technology, love, beauty, power -- it's all tradable."
So-called concubine villages -- places where lotharios keep "second wives" in comfort and seclusion -- are now spread across the nation, in booming cities such as Dongguan, Chengdu and Shanghai.
So common is the practice that it has spawned an industry of private detectives snooping on cheating husbands and their paramours. One such agency, called Debang, based in the western city of Chengdu, underscores how "first wives" are fighting back.
Debang was started by divorced women with one goal: to help desperate wives ferret out their double- and triple-timing husbands and make them pay for their indiscretions.
Debang wouldn't comment, but informed people say the firm has expanded into several cities and has a staff of more than 100.
The mistress boom is contributing to a surge in divorces -- and fierce battles over property when relationships collapse. Not long ago, Beijing amended the country's marriage law to make men who indulge in mistresses pay heavy penalties and to give their spouses greater rights in separations.
Now, local governments are starting to take action.
This year the city of Nanjing issued an order for all public officials to register their extramarital relationships. In Guangzhou, a prosperous city in the south, a major university issued stern warnings to female students about having affairs and wrecking marriages. And last month, state media reported that Hainan province had stipulated that party members who kept mistresses or had children outside of marriage would be expelled.
Government leaders worry that philandering also could have detrimental effects on China's economy and the credibility of the Communist Party.
State-run banks and agencies have lost billions of dollars to embezzlement and fraud, many at the hands of officials seeking money to support their golden canaries. In a government review of 102 corruption cases in several Guangdong province cities a few years ago, every one involved an illicit affair.
"If a government official has a mistress, there must be some corruption," says Sun Youjun, a private investigator in Shanghai. "Visits to high-end hotels are not easy with officials' incomes."
Like most bureaucrats, Li Xin had a monthly paycheck of no more than a few hundred dollars. But as deputy mayor for a city of 8 million that's a regional industrial and rail center, Li could easily boost his income. He collected bribes from more than 40 businesses in exchange for helping them with land deals, commodity sales and construction projects, according to interviews and to reports in state-owned media.
Li had a penchant for drinking, people familiar with the case said, and he showered his ladies with expensive gifts and even sheltered some of them in homes.
He met his match in Li Yuchun, the woman who took the photo of him in the hotel room. The two started out as lovers, according to some accounts, and then became business partners.
Li Yuchun exposed him after she learned he was laundering money. After she blew the whistle, she also was sent to jail this summer for five years for harboring a criminal, her brother -- a sentence that drew public outcry over the risks of exposing corrupt government officials.