University of California

Genetic variability in a thelytokous form of Aphytis mytilaspidis (Le Baron) (Hymenoptera: Aphelinidae)


Yoram Rössler
Paul DeBach

Authors Affiliations

Yoram Rössler was with the Institute for Nature Conservation Research, Tel Aviv University, Israel; Paul DeBach was Professor of Biological Control and Entomologist in the Experiment Station, Riverside.

Publication Information

Hilgardia 42(5):149-175. DOI:10.3733/hilg.v42n05p149. September 1973.

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The possible mechanisms for generation of genetic variability in a thelytokous form of the parasitic wasp, Aphytis mytilaspidis, were explored. Through cytological studies the thelytokous form was found to retain the meiotic divisions in egg maturation. Restoration of diploidy is achieved through the fusion of two sister nuclei of the second meiotic division (terminal fusion). Heterozygosity can be retained for such loci as undergo crossing over. Males are produced by the thelytokous form in a low frequency; both thelytokous males and females are sexually functional; and sexual processes occur in the thelytokous population.

In zones of overlap, gene flow may occur between the thelytokous form and a related arrhenotokous form, thus adding to the genetic variability of the thelytokous form.

Since genetic variability can be generated in the thelytokous form through genetic recombinations in meiosis, through sexual processes within the population, and by introgression with the arrhenotokous form, thelytoky does not represent an evolutionary dead end.

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Rössler Y, DeBach P. 1973. Genetic variability in a thelytokous form of Aphytis mytilaspidis (Le Baron) (Hymenoptera: Aphelinidae). Hilgardia 42(5):149-175. DOI:10.3733/hilg.v42n05p149
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