An item page on the e-commerce site taobao.com. [Photo/chinadaily.com.cn]

Every summer the craze for fireflies sweeps China. As the Chinese Valentine's Day, or Qixi, draws near, online firefly selling is getting busier.

The amount of fireflies trade online has exceeded 10 million this year, a 10-fold rise compared to the same period in 2014, an investigation by Jiangsu Qinghuan Volunteer Service Center has revealed.

"Thirty-seven e-shops on the e-commerce site taobao.com are selling live fireflies, among which 17 have made more than 50,000 transactions. Orders have reached as high as nearly 50,000 on a single item, and the total number of fireflies traded on these e-shops have gone beyond 10 million," said a volunteer at Qingshan Volunteer Service Center.

Many online shops sell flickers in sets, such as a jar of 55 claimed to represent "I love you", as part of promotions that target the Chinese Valentine's Day, which falls on Aug 20 this year. Each flicker in these sets costs four to five yuan ($0.63 to $0.78). Since these creatures die easily during delivery, some sellers pack 20 percent more in the package.

"We've been watching this problem on taobao.com for years. This year the selling seems to be more centralized. In the past, customers could place orders on number of fireflies as they wished. But they now have to buy fixed number of fireflies in sets this year," said Fang Jianbo at Qinghuan Volunteer Center. He said thirty fireflies with six given for free are sold at about 160 yuan, which is the lowest price for a set.

Many of the sellers claim their fireflies to be captive-bred. Experts say that nearly 99 percent of these "captive-bred" fireflies are fake, for the artificial propagation of fireflies is costly, nearly twice as the price of the fireflies sold online.

According to investigations by an environmental organization in Jiangsu province, there have been more than 60 firefly exhibitions nationwide this year. Such exhibitions, however, are deemed as harmful to the environment, according to experts.

"It threatens the indigenous ecosystem and the species being brought in may not be able to survive," said Fu Xinhua, a biologist at Huazhong Agricultural University in Wuhan, Hubei province. Fu suggested people go to the wild or the santuaries to watch fireflies.

Fireflies were once a familiar part of summer evenings in much of China. But the tiny flashes that used to light up fields have dwindled or lost, experts say, to pollution and altered natural habitats.