Order Hymenoptera

Family Vespidae

Recent studies and investigations in Polistes have shown the complexity of this genus to be determined. Several taxonomical changes have been applied and one of the affected wasps has been Polistes canadensis, quite common in the reserve and with lots of records. Nowadays, Polistes is composed of various subgenera all over the world and two of them are present here: Epicnemius and Aphanilopterus. A subgenus is an intermediate category between genus and species which groups species related among them.

The species of the subgenus Aphanilopterus of Buenos Aires are mainly red. Some have distinctive characteristics which tell them apart. Such is the case of Polistes simillimus, with its yellow dots on the abdomen. In the cases were identification is not possible species have been grouped under Polistes (subg. Aphanilopterus) sp.. Some species of this group found in this area are Polistes canadensis, P. ferreri, P. consobrinus and P. lanio. So, all the previous records under Polistes canadensis in the site have been moved to Polistes (subg. Aphanilopterus) sp.

The species of the subgenus Epicnemius which are found at the reserve are mainly black. The few representatives of this subgenus may be differentiated without any trouble. Here we have recorded Polistes cinerascens. Another wasp of this subgenus, Polistes billardieri, differs from P. cinerascens in its brown legs and antennae, but it does not seem to be present either in CABA or in the surroundings.

Polistes adults feed on vegetal material whereas larvae are fed on insects or their immature stages. The nest is built with vegetal material mixed with saliva. It is aerial and waterproof. It has only one plate of cells that are held to a support by means of a peduncle..