Hu said: "There is no need to worry too much about negative consequences. Most butterflies feed on wild plants, which are not of economic importance. If a mass hatching occurs, this indicates that there is enough food and a suitable environment to support a large population."

Elsewhere in the province's northwestern parts, including the river valleys of the Upper Yangtze, Lancang and Nujiang rivers, butterfly hatchings resemble those in the valley.

In southern Yunnan, butterfly hatchings are more frequent.

For example, in the Xishuangbanna Dai autonomous prefecture, billions of Common Emigrant (Catopsilia pomona), a medium-sized butterfly species named for its habit of migrating, gather on river banks in the summer, Hu said.

To protect diversity, Hu said that access to the valley needs to be limited. "Tourists entering the area must follow the rules, and catching butterflies is strictly forbidden. The Butterfly Valley Museum can also help educate people on nature and the importance of butterflies," he said.

Yang Zhenwen, curator of the museum, said that joint efforts over the years on protection have allowed the butterfly population to stabilize.

According to Yang, the population of Jungle Queens was measured at about 109 million in 2016, and last year it rose to 150 million.

Zhou said: "Once destroyed, biodiversity cannot be renewed. So, protecting existing biodiversity in the valley is an important task that must be passed down from generation to generation."