Common name(s): None that I know of
Distribution: Apart from Hong Kong and Singapore, this species is very widely distributed across Asia, and can even be found in Australia.
This is a small, prettily marked species. It is not often noticed, partly because of its size, but on closer inspection has several points that readily identify it.
Specimens from Hong Kong have a mainly brown base colour. The legs and antennae are a lighter colour. The end of the first abdominal segment displays a narrow yellow ring. The last three segments are yellow, inter-marked with brown. The wings are the most distinctive feature; on the edge of each forewing, which are clear, there is a noticeable dark spot. Specimens from Singapore are similar but the brown ground colour seems to be lighter and more vivid in life, often nearly red, with more clearly demarcated black and yellow markings. Some individuals, however, are darker. This is one of the smaller Polistes species, between 11mm and 14mm in length on average.
This is a very common species in Hong Kong, living and nesting in both urban areas and out in the countryside. It is often overlooked due to its small size - watching one fly at a distance, it is easy to mistake it for a Parapolybia species. They often nest much higher than many Polistes species, in trees such as Casuarina or Hibiscus tiliaceus (sea hibiscus), though sometimes lower in bushes, often in ornamental plants in parks and gardens, or even man-made structures. The nest is usually not very big but contains many cells, and the colonies can get quite large, with more than a hundred wasps not uncommon. Nests start off round like most other species but take on a unique shape, with several distinct lobes on the comb, which curve upwards at the edges, as they mature. Like other Polistes wasps, this species appear to prey mainly on caterpillars. They are pretty unaggressive and colonies can be observed at a respectful distance, but should never be provoked.
In contrast, Polistes stigma is fairly uncommon in Singapore, and is more frequently found in mangrove habitats, although it can occasionally be found in mature secondary forest and parks near the forest fringe. The nests tend to be lower than in Hong Kong, and built under the large, broad leaves of plants such as Dillenia suffruticosa, but are otherwise like those in Hong Kong in terms of colony size and nest structure. The photos above are of individual wasps and nests in Hong Kong, while those below are from Singapore.
Note: Previously, I mentioned elsewhere on this website that there are three colour forms of Polistes stigma in Singapore. However, I realized that very dark individuals sometimes appear on the same nests as the typical red, black and yellow colour form, and thus it is just variation in colour, not enough to constitute a separate form. What I used to call the “black colour form” is in fact Polistes tenebris, a species new to science, of which I am a co-describer. The same paper also lists other newly-described species similar to Polistes stigma from Vietnam. It may be that many other “colour forms” or “subspecies” in other countries might prove to be closely related but different species.
