Found a group of more than 20 rove beetles (family: Staphylinidae) under some straw at the edge of a rice field. This species is probably Paederus fuscipes (aobaarigatahanekakushi).

“Staphylinidae are one of the largest families of beetles, with over 45,000 species known worldwide and probably over 75% of tropical species still undescribed.” (From University of Florida Institute of Food and Agricultural Sciences:

Paederus fuscipesPaederus fuscipesPaederus fuscipes

Coleoptera: Staphylinidae
Paederus fuscipes