African Arthropods/Encyrtidae

There are more than 640 described species of Afrotropical Encyrtidae in about 130 genera. More than 380 of these species have been found in South Africa.

Diagnostic features of Encyrtidae

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In macro photographs, encyrtids are often recognizable using these features:

  1. Large mesopleuron, usually covering more than half of the thorax (mesosoma) in side view.
  2. Mid coxae join the thorax near the middle of the mesopleuron.
  3. Mesoscutum transverse (width greater than length), and generally not segmented by notauli.
  4. The axillae are usually visible as triangles with two long sides, one adjacent to the mesoscutum and the other adjacent to the scutellum; the short side of the triangle is adjacent to the base of the forewing. The axillae touch, or nearly touch, medially; appearing as wedges between the mesoscutum and the scutellum.
  5. Cercal plates (at the base of the cercal bristles) are advanced; rather than being near the posterior tip of the metasoma (abdomen); they are usually within the anterior (front) two-thirds of the metasoma.
  6. In Encyrtidae with fully developed wings, the marginal vein of the forewing is usually shorter than stigmal vein; there is also an oblique band on the forewing that lacks setae (a linea calva).

Encyrtidae - genera

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An illustrated key to the encyrtid genera of the Afrotropics was published in 1979.[1]. This key has been updated here to include some taxonomic changes and images with appropriate Creative Commons licenses.

Many encyrtid genera are difficult to identify from photographs, but some are more recognizable. The photographs in the gallery below show some of the more recognizable ones. Please note that identifications of any chalcidoid wasps from photographs are difficult, and all should be treated with some doubt, unless the specimen was collected and details checked with a microscope.

Encyrtidae for biological control of crop pests

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Many encyrtid species are parasitoids of scale insects, some of which are pests that reduce productivity of agricultural crops across the world. Many scale insects have spread to countries where they have few natural enemies; in these cases, the introduction and spread of their wasp parasitoids can be used as a form of biological control to reduce their economic impact.[2][3]

References

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  1. Prinsloo, G. L., & Annecke, D. P. (1979). A key to the genera of Encyrtidae from the Ethiopian region, with descriptions of three new genera (Hymenoptera: Chalcidoidea). Journal of the Entomological Society of southern Africa, 42(2), 349-382. PDF
  2. Kapranas, A., & Tena, A. (2015). Encyrtid parasitoids of soft scale insects: Biology, behavior, and their use in biological control. Annual Review of Entomology, 60, 195-211. https://www.annualreviews.org/doi/10.1146/annurev-ento-010814-021053
  3. Legner, E. F., Economic gains & analysis of success in biological pest control. University of California, Riverside. http://www.faculty.ucr.edu/~legneref/identify/museum5.htm (accessed 10 March 2024)