Two newly recorded species join Thailand's aquatic insect fauna

Caddisflies are an order of aquatic insects with high diversity. In Thailand, more than 1,000 caddisfly species are known to occur, and a recent study in the journal Check List shows that their diversity in the country is even greater than previously suggested.

Scientists Rungnapa Somnark from Khon Kaen University and Narumon Sangpradub from the Center of Biodiversity Excellence, Chulalongkorn University recorded, for the first time, two caddisfly species that were previously not documented as part of Thailand's fauna. They were able to catch the insects using black-light traps set up along water streams. The field study took place in the summer of 2017 at Thap Lan National Park, which is a part of Dong Phayayen–Khao Yai Forest Complex, a Natural World Heritage site in the north-eastern Thailand.

The two newly-recorded caddisfly species are Diplectrona erinya, a brown insect previously only known from Tam Dao in Vietnam, and Diplectrona extrema, yellowish-brown in color and distributed in Borneo, Sumatra, and Java.

They both belong to the genus Diplectrona, which now has 10 documented representatives in Thailand.

The researchers suggest they are probably rare in the country.

"Our study suggests that two newly reported species occur at low densities, which highlights the continuing need for efforts to conserve the [Thap Lan National] park and to conduct more studies on the caddisfly fauna," they say in conclusion.