But although tiny lighting bugs add romantic ambience for couples in love, they're not easy to transport and feed, firefly expert Fu Xinhua said.

"Many suppliers claim they breed lighting bugs in captivity, but the fact is, more than 99 percent of them catch the bugs in the wild due to the low cost," said Fu, who teaches entomology at Wuhan's Huazhong Agricultural University and spends seven months every year on firefly research in the field.

"Moreover, up to 50 percent of the fireflies may die on their way to create human romance," Fu added.

Chen Yu, another online shopkeeper from taobao.com, said that 400 fireflies she once shipped all died before they reached her customers because of the heat in the postal parcels.

Li's bug supply came from a firefly farm in Ganzhou, Jiangxi province. The farm's owner, He Jianming, acknowledged the difficulty of transporting fireflies, especially during summer.

"They easily die in hot weather," he said. "We have to send the fireflies to customers by air-conditioned buses in summer instead of by express delivery, as at least 20 percent of the fireflies could die on the way."

He said that in order to keep the firefly cost to 2 yuan each, he built his farm outdoors. "The usual cost of breeding fireflies is around 8 to 20 yuan each — far more expensive than the price you could find online," said He.

Fu said selling fireflies online is the wrong way to develop the mainland's firefly industry chain, and contrasts with tourism-oriented firefly protection zones in Japan, Malaysia and Thailand.

"Many may argue that after the romantic moment, they could let the firefly go into the wild, but that would bring another problem — a biological invasion. If you place the lighting bugs somewhere other than their own environments, similar local species could be threatened," said Fu.

He added that in the wild, fireflies have a life span of 10 to 14 days, while they can survive for only two to five days if bought online because of the injuries the insects suffer from capture and transportation.

"I don't think it makes sense to connect the lighting bugs with Qixi simply because the primary purpose of light in adult beetles is to be used for mate selection," Fu added.

The first firefly park in the mainland opened in Fujian province's Xiamen in 2010. It has more than 10,000 fireflies in a wetland valley that is a favorable ecological environment for the bug. More than 10,000 people have visited the park, which only opens in summer — the best time of the year to observe the insect.