Encarsia of Australia
Ordo: Hymenoptera
Familia: Aphelinidae
Name
- Encarsia Förster, 1878 Wikispecies link
Introduction
Encarsia Förster is a large, cosmopolitan genus of tiny parasitic wasps of the family Aphelinidae, currently containing about 400 described species[1]. The number of existing species is expected to be several times higher because many species are still undescribed[2]. The adult wasps, tiny insects with 1-2 mm in size, are primarily parasitoids of sessile stages of Sternorrhyncha, in particular whiteflies (Aleyrodidae) and scale insects (Diaspididae). A few species are known to parasitize aphids, eggs of shield-back bugs (Plataspidae), and eggs of Lepidoptera. Females are mostly developing as primary endoparasitoids whereas males are commonly hyperparasitoids of the same or other species[3][4].
Species of Encarsia have been considered as the most efficacious group of biocontrol agents of whitefly pests on a broad range of agricultural crops. Recently their economic importance has been recognized worldwide and more attention has been given to their taxonomy. This is especially true of the Encarsia species parasitic on whiteflies. New species are being continuously added and there is evidence for the presence of complexes of cryptic species within several of these described species.
Preparation and identification
Despite their importance, the identification of many Encarsia species is still very difficult, mainly because of their very small size necessitating laborious slide-mounting for taxonomic study, the poor condition of most of the early (and some recent) type material, and their apparent extreme diversity. The taxonomy of Encarsia is primarily based on morphological characters that can only be examined in slide mounted specimens using contrast enhancing techniques like phase contrast or differential interference contrast (see detailed instructions for slide-mounting of Encarsia specimens).
Diagnosis
For a positive diagnosis of Encarsia (females), the presence of the following character states is required:
- Fore and hind tarsi with five tarsomeres
- Antenna (excluding radicle) with eight antennomeres
- Scutellum with two pairs of setae
- Marginal vein longer than submarginal vein
- Postmarginal vein absent
- Stigmal vein very short, less than one-quarter of the length of the marginal vein
The closely related genus Coccophagus differs from Encarsia primarily in having six or more setae on the scutellum. The generic circumscriptions of the genera of the aphelinid subfamily Coccophaginae are currently being reassessed, as are their phylogenetic relationships.
Species pages
- Encarsia accenta Schmidt & Naumann
- Encarsia citrina (Craw)
- Encarsia iris (Girault)
- Encarsia nigriventris (Girault)
- Encarsia pergandiella Howard
References
- ↑ Noyes, J.S. (2003) Universal Chalcidoidea database.
- ↑ Heraty, J.M., Polaszek, A. & Schauff, M.E. (2008) Systematics and Biology of Encarsia. Chapter 4, pp. 71-87 in: Gould, J., Hoelmer, K. & Goolsby, J. (Eds), In: Classical Biological Control of Bemisia tabaci in the United States. A review of interagency research and implementation. Progress in Biological Control 4. . Springer Science and Business Media B.V. 1-343.
- ↑ Williams, T. and Polaszek, A. (1996) A re-examination of host relations in the Aphelinidae (Hymenoptera: Chalcidoidea). Biological Journal of the Linnaean Society 57: 35-45. doi
- ↑ Hunter, M.S. and J.B. Woolley (2001) Evolution and behavioral ecology of heteronomous aphelinid parasitoids. Annual Review of Entomology 46: 251-290. PDF
