Abstract
The reproductive relations and the probability of hybridization between an arrhenotokous and a thelytokous form ofA. mytilaspidis were investigated so as to determine the significance of thelytoky in biosystematic studies and its value as a taxonomic character.
Gene markers were utilized to detect and follow the various phases of the introgressive process between the arrhenotokous and thelytokous forms.
The two forms show only a partiel sexual isolation, the major barrier is prezygotic, arrhenotokous males are much less efficient in recognizing the thelytokous female and copulating with them.
A thelytokous female, once inseminated, will utilize the sperm as efficiently as the arrhenotokous female. Viable and fertile hybrids are produced and when conditions are favorable and a suitable host is present the introgressive process will result in a hybrid swarm. The hybrids acquire traits carried by both ancestral stocks.
Résumé
Les relations reproductrices et la probabilité d'hybridation entre une forme thélytoque et une forme arrhénotoque deAphytis mytilaspidis ont été étudiées afin de définir la signification du mode thélytoque dans les recherches de biosystématique et sa valeur en tant que caractère taxonomique. Des marqueurs génétiques ont été utilisés pour détecter et suivre les différentes phases des processus de transition entre les formes arrhénotoques et thélytoques.
Les deux formes présentent un isolement sexuel partiel, la principale barrière étant prézygotique. Les mâles arrhénotoques sont beaucoup moins efficaces dans la reconnaissance des femelles thélytoques et dans l'accouplement avec celles-ci.
Une femelle thélytoque, une fois inséminée, utilise le sperme aussi bien que la femelle arrhénotoque. Des hybrides viables et fertiles sont produits et lorsque les conditions sont favorables et un hôte convenable disponible il en résulte une descendance hybride qui possède des caractères issus des deux souches ancestrales.
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The investigation is a part of a Ph. D. dissertation submitted to the University of California, and was supported by grants Nos. GB 7444 and GB 17829 of the National Science Foundation.
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Rössler, Y., DeBach, P. The biosystematic relations between a thelytokous and an arrhenotokous form ofAphytis mytilaspidis (Le Baron) [Hymenoptera: aphelinidae] I. The Reproductive relations. Entomophaga 17, 391–423 (1972). https://doi.org/10.1007/BF02371647
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DOI: https://doi.org/10.1007/BF02371647