HANGZHOU - It was meant to be a romantic evening under the glittering lights of fireflies by a scenic lake in Zhejiang province, eastern China.

But when the 30,000 bugs refused to glow, a mob of angry Chinese tourists smashed the organiser's office after their demand for a refund was not met.

Ticket sales for the opening night on Wednesday of the summer firefly display at the Xiang Lake plaza in Hangzhou had been brisk. Some 10,000 people had paid 30 yuan (S$6) for a ticket and duly appeared at the venue in a state of high excitement, Times of London reported.

The early summer in eastern China is famous for firefly viewings, and tourist boards have spared no effort in turning the insects into an annual attraction during the May national holidays.

Unfortunately, as the authorities in Hangzhou discovered, crepuscular bioluminescence is a fragile and unpredictable thing: the fireflies' bottoms do not glow when the temperature is too low.

As darkness fell and the scheduled 7.30pm start came and went, the skies at the Xiang Lake plaza remained dark. That remained the case for the next two hours - a delay that caused many in the crowd to become irascible.

In an instant, tempers snapped. Hundreds besieged the lake's management office demanding a refund and an explanation. When neither was forthcoming, they smashed the doors and windows. They later turned on other tourist facilities near by, meting out physical vengeance for their spoilt soirée.

"We can live with the fact that no insects showed up, due to (the cold), but the organiser should have stopped selling tickets and offered us a refund," said one tourist quoted by local media.

According to a report on Thursday from Dushi Kuaibao, a tabloid owned by Hangzhou Daily Press Group, the event organiser has decided to cancel the firefly show and visitors can claim refunds in the next 10 days.