Polistes japonicus

Common name(s): None that I am aware of. The Chinese name translates to "Japanese paper wasp", although it can be found in much of China, Taiwan and Korea.

This species can be found throughout Japan, Korea, Taiwan and much of mainland China. It is fairly common in Hong Kong, and can be found in both urban and rural areas. It is often mistaken for Polistes olivaceus, but can be differentiated by its smaller size (14mm to 20mm) and differences in markings. The markings on the abdomen are fine and straight, as opposed to the curved markings on the abdomen of Polistes olivaceus. Its antennae are also reddish brown, as opposed to Polistes olivaceus which has yellow antennae.

Nests of this species are generally built in bushes and small trees. The colony size is usually small to medium, reaching a maximum of several dozen wasps but usually much fewer than that. One distinctive trait seen in nests of this species is that the cocoon caps of cells containing pupae are greenish yellow. No other species in Hong Kong shows this trait, although I am not sure about other species in Taiwan or Japan.

This species is gentle and unaggressive, attacking only if the nest is disturbed.

The photos below show a newly initiated nest, a young nest and a mature nest respectively.