Description

Members of the subfamily Stizinae prey on Homoptera and Orthoptera. There are relatively few species. The large cicada killer, Sphecius speciosus Drury is one of the more common species in North America. it stores its nests with adults of the periodical cicada, Magicicada septendecim L. (Riley 1892). Wasps appear in the field in July and August. The cicada is completely paralyzed by the sting, but it has been found that they will, under right conditions, persist in good physical conditions for more than one year. The prey is of such a large size that the wasp has difficulty in transporting to the nest. Thus, she adopts an expedient means whereby the prey is dragged to some height in a tree, after which she glides with it as far as possible toward the nest. The procedure may be repeated several times until the nest is reached. Sometimes two cicadas are placed in a single cell, but usually only one. The egg is laid at one side of the thoracic venter, and hatching ensues in 2-3 days, with larval feeding completed in a week. The cocoon is spun in the cell in the soil and is conspicuous by having two irregular rows of "pores" at one side which are thought to serve for ventilation (Clausen 1940/1962).

Finnamore & Michener (1993) treated this widespread group as a subfamily of Nyssonidae in the Apoidea. There are >300 species. Adults are medium small to large and black, black and red, or black and yellow. Prey are Orthoptera or Mantodea (Dictuoptera), although members of one genus are cleptoparasitic on Sphecidae and probably Bembicinae. In Norther America there are 11 species in 3 genera (one species in Canada).

The effect of the sting of Sphecius on the cicada causes lesions to form in the main parts of the central nervous system, similar to those produced by certain chemical pesticides, such as pyrethrins (Hartzell 1935).

Krombein (1984, 1985) revised the Sri Lankan species.

References: Please refer to <biology.ref.htm>, [Additional references may be found at: MELVYL Library]

Krombein, K. V. 1984. Biosystematic Studies of Ceylonese Wasps, XIII: A Monograph of the Stizinae (Hymenoptera: Sphecoidea, Nyssonidae) Smithsonian Contrib. Zool. 388: 37 pp., 30 fig.