Evaniidae

The ensign wasps are 1.7-17 mm long. The body color is predominantly black or dark brown to reddish brown, sometimes with white markings. The abdomen (metasoma) is small and inserted high on the thorax (mesosoma). This unusual body shape, and the habit ofmoving the abdomen up and down when the wasp walks, gives the impression of a waving flag, hence the name ensign wasp. Biological information from Europe and North America indicates that most evaniids are parasites in the oothecae of cockroaches. Female evaniids generally run about quickly in locations where hosts deposit oothecae, and they may prefer those freshly deposited. Evaniid eggs are deposited singly in the ootheca. There are 3-5 larval instars; the first-stage larvae may feed on one cockroach egg, but later instars consume several eggs within the ootheca. The prepu-pal stage may diapause during an unfavorable season.

Some evaniid genera with species that parasitize domiciliary cockroach species include: Brachygaster with Ectobius panzeri; Evania with Periplaneta americana, P. australasiae, and Blatta orientalis; Hyptia with Parcoblatta pennsylvanica; Proseva-nia with Periplaneta americana, P. australasiae, Blatta orientalis, and Blattella germanica; Szepligetella sericea with P. americana and P. australasiae; and Zeuxenia with Loboptera spp.

Evaniid eggcase parasite, Evania appendigaster The adult is 5.5-7 mm long and the body is black; the wings are clear. It is the largest species in the family, the other species are usually less than 5 mm long. It is a parasite of several domiciliary cockroaches, including Periplaneta americana, P. aus-tralasiae, and Blatta orientalis; butsome records may be in error, including those for Blattella germanica and Leucophaea maderae. A related evaniid species, E. dimidiata, is reported as a parasite of B. orientalis in Egypt.

Eggs are deposited singly, and usually there is only one per ootheca. Oviposition occurs after the female crawls over the ootheca surface, and rests with the axis of her body parallel to the axis of the ootheca as it lays on its side. As the ovipositor punctures the ootheca, the female may remain in place for about 15 min. The evaniid larva feeds on the cockroach eggs and development through five larval instars is completed within 60 days. The larva consumes the entire contents of the ootheca. The pupa is formed within the ootheca, and the adult wasp cuts an exit hole to emerge. Adults live 2-3 weeks with food and water. There are three or four generations per year, depending on environmental conditions. This species is widely distributed, and may be cosmopolitan.

Ensign wasp parasite, Prosevania punctata The adult is about 4 mm long, and the body is black. Eggs are deposited singly into an ootheca, and only one per ootheca. The female Periplaneta americana may show instinctive hostility towards evaniid females approaching a freshly deposited ootheca. Oviposition usually occurs after the female is oriented so that she is facing the keel of the ootheca, but egg-laying may occur in other positions. Females apparently do not distinguish between parasitized and unparasitized ootheca. There is no apparent preference for freshly deposited oothecae or those several weeks old, but the oothecae carried by cockroaches are not attacked. The development period in Blatta orientalis is 40-57 days; development in P. americana is about 127 days.

The adult emerges from the ootheca through a 4-mm diameter hole. There are two or three generations per year. Adults live about 20 days. This species is widely distributed and occurs in eastern USA, Europe, and the Middle East, but may be cosmopolitan. It can occur in large numbers indoors, and achieve pest status.

Other evaniids Several species of Hyptia are parasites of Parcoblatta cockroaches, including H. dorsalis, H. harpyoides, H. retic-ulata,and H. thoracica.These wasps may be encountered indoors when fireplace logs with Parcoblatta under the bark are brought into houses.

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