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The biology of Physcus seminotus Silv. and P. subflavus Annecke & Insley (Aphelinidae), parasites of the sugar-cane scale insect Aulacaspis tegalensis (Zhnt.) (Diaspididae)

Published online by Cambridge University Press:  10 July 2009

J. R. Williams
J. R. Williams
Affiliation:
Mauritius Sugar Industry Research Institute, Réduit, Mauriiius
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Extract

Physcus seminotus Silv. (properly P. sp. nr. seminotus Silv.) and P. subflavus Annecke & Insley (Aphelinidae) are parasites of the sugar-cane scale insect Aulacaspis tegalensis (Zhnt.) (Diaspididae) in East Africa and they have been purposely introduced into Mauritius where A. tegalensis is an important pest. P. seminotus has brachypterous, flightless females and P. subflavus winged females but their biology is essentially similar. The parasites are arrhenotokous and fertilised and unfertilised eggs are deposited in different sites concomitant with development of female and male larvae on different primary hosts. Female larvae develop endoparasitically in A. tegalensis from fertilised eggs deposited in the host's body cavity. Male larvae develop ectoparasitically on immature Hymenoptera in A. tegalensis from unfertilised eggs deposited in the air-filled cavity of the latter's integumentary remnant. The males of the two Physcus spp. are therefore hyperparasitic and they frequently develop on the immature stages, both male and female, of their own kind (autoparasitism). Unfertilised eggs are laid by virgin females and also by mated females, the latter being able to deposit fertilised and unfertilised eggs at will, depending on the egg site encountered. Sexual dimorphism occurs at all stages, including the deposited egg. The preovipositional adult is the preferred stage of A. tegalensis for deposition of fertilised eggs and development of females is most rapid in such hosts. Development in young hosts is arrested until the hosts have grown to virtually their full size. The host of a male is apparently a matter of chance in so far as evelopment will occur on larval and pupal Hymenoptera of various species found in the empty, inflated, brittle integument of parasitised A. tegalensis. Only one individual, whether male or female, develops per host. Oviposition behaviour of mated females is such that superparasitism is largely avoided but it is liable to occur frequently when virgin females oviposit. Adult females will feed on the body fluids of A. tegalensis that are released by insertion of the ovipositor and also on sugary fluids. They live a month or more, ovipositing continually at a gradually decreasing rate, and laying usually 50–100 eggs.

Type
Research Paper
Information
Bulletin of Entomological Research , Volume 61 , Issue 3 , February 1972 , pp. 463 - 484
Copyright
Copyright © Cambridge University Press 1972

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References

Annecke, D. P. & Insley, H. P. (1970). New and little known species of Azotus Howard, Ablerus Howard and Physcus Howard (Hym., Aphelinidae) from Africa and Mauri tius.—Bull. ent. Res. 60, 237–251.CrossRefGoogle Scholar
Broodryk, S. W. & Doutt, R. L. (1966). Studies of two parasites of olive scale, Parlatoria oleae (Colvée) II. The biology of Coccophagoides utilis Doutt (Hymenoptera: Aphelinidae).—Hilgardia 37, 233–254.Google Scholar
Doutt, R. L. (1959). The biology of parasitic Hymenoptera.—A. Rev. Ent. 4, 161–182.Google Scholar
Fisher, R. C. (1971). Aspects of the physiology of endoparasitic Hymenoptera.—Biol. Rev. 46, 243–278.CrossRefGoogle Scholar
Fisher, T. W. (1961). Biology of Physcus sp. (Eulophidae, Aphelininae) from Burma.—J. econ. Ent. 54. 444–446.Google Scholar
Flanders, S. E. (1967). Deviate-ontogenies in the Aphelinid male (Hymenoptera) associated with the ovipositional behavior of the parental female.—Entomophaga 12, 415–427.CrossRefGoogle Scholar
Flanders, S. E. (1969). Alternative differential mortality of the sexes concomitant to sex differentiation in host relations.—Entomophaga 14, 335–346.Google Scholar
Gerling, D. (1966). Studies with whitefly parasites of Southern California. I. Encarsia pergandiella Howard (Hymenoptera: Aphelinidae).—Can. Ent. 98, 707–724.CrossRefGoogle Scholar
Girault, A. A. (1939). Descriptions of some Chalcid wasps.—Qd Nat. 11, 14–23.Google Scholar
Greathead, D. J. (1970). White sugar-cane scales (Aulacaspis spp.) (Diaspididae: Hemiptera) in East Africa with notes on their natural enemies.—E. Afr. agric. For. J. 36, 70–76.Google Scholar
Salt, G. (1961). Competition among insect parasitoids.—Symp. Soc. exp. Biol. 15, 96–119.Google Scholar
Simmonds, F. J. (1943). The occurrence of superparasitism in Nemerit is canescens Gray.—Revue can. Biol. 2, 15–58.Google Scholar
Taylor, T. H. C. (1935). The campaign against Aspidiotus destructor, Sign. (with three sections by R. W. Paine) in Fiji.—Bull. ent. Res. 26, 1–102.CrossRefGoogle Scholar
Williams, J. R. (1970). Studies on the biology, ecology and economic importance of the sugar-cane scale insect, Aulacaspis tegalensis (Zhnt.) (Diaspididae), in Mauritius.—Bull. ent. Res. 60, 61–95.Google Scholar
Zinna, G. (1962). Ricerche sugli insetti entomofagi. III. Specializzazione entomoparassitica negli Aphelinidae: interdipendenze biocenotiche tra due specie associate. Studio morfologico, etologico e fisiologico del Coccophagoides similis (Masi) e Azotus matritensis Mercet.—Boll. Lab. Ent. agr. Filippo Silvestri 20, 73–184.Google Scholar