Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae) Löfstedt, C.; Herrebout, W.M.; Menken, S.B.J. Published in: Chemoecology Link to publication Citation for published version (APA):Löfstedt, C., Herrebout, W. M., & Menken, S. B. J. (1991). Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae). Chemoecology, 2, 20-28. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Biosynthetic routes to the pheromone components identified are proposed on the basis of fatty acid pheromone precursors found in the pheromone glands. A phylogenetic tree for the genus is constructed based on allozyme frequency data and changes in pheromone composition are superimposed on this tree. We suggest that the ancestral ermine moth pheromone is a mixture of (Z)-ll-and (E)-ll-tetradecenyl acetate and the corresponding alcohols, and a scenario of how present-day patterns evolved is outlined. The pheromone differences among the three species using spindle tree as their host-plant might have evolved through reproductive character displacement upon secondary contact between populations that had already diverged genetically in allopatry. Yponomeuta species is emphasised by (1) the function of pheromone components of some of the species as behavioural antagonists to other species, (2) the cross-attraction under experimental conditions between allochronic species with similar pheromones, and (3) the formation of hybrids in the laboratory between species that are isolated in nature by pheromone differences.

Small ermine moths (Yponomeuta): their host relations and evolution Menken, S.B.J.; Herrebout, W.M.; Wiebes, J.T.

In field‐trapping experiments the unsaturated analogues (E)‐6‐, (E)‐12‐, and (Z)‐12‐tetradecenyl acetate were as attractive to male Yponomeuta rorellus Latr. as the native pheromone component tetradecyl acetate. All four analogues attracted more males than virgin females did, whereas (Z)‐6‐, (E)‐11‐, (Z)‐10‐ and (Z)‐11‐tetradecenyl acetate were essentially non‐attractive. Addition of 1–30% of (Z)‐11‐tetradecenyl acetate to the pheromone tetradecyl acetate reduced the attraction to less than 2%. Flight tunnel experiments with Y. rorellus confirmed the activity of the (E)‐6‐ and (E)‐12‐tetradecenyl acetates and demonstrated the activity of (E)‐7‐tetradecenyl acetate as well. These analogues elicited orientation behaviour, upwind flight and landing at the odour source as frequently as the native pheromone did. Single sensillum recordings from male Y. rorellus showed two types of cells in most sensilla. A large spike amplitude cell was stimulated by tetradecyl acetate and the unsaturated analogues (E)‐11‐, (E)‐6‐ and (E)‐12‐tetradecenyl acetate, and to a lower extent by the (Z)‐6‐, (Z)‐11‐ and (Z)‐12‐isomers. A cell with medium spike amplitude was stimulated by (Z)‐9‐tetradecenyl and (Z)‐11‐hexadecenyl acetate. Some sensilla contained a third cell firing with a small spike amplitude which was activated by (Z)‐11‐tetradecenol. Thus the tetradecyl acetate receptor was stimulated not only by the behaviourally active analogues, but also by behavioural antagonists. The interaction of (E)‐11‐tetra‐decenyl acetate and tetradecyl acetate with the same antennal receptor cell was also demonstrated in Y.cagnagellus. Electrophysiological discrimination between behavioural attractants and antagonists and the role of behavioural antagonists in the interspecific relations between Y.rorellus and sympatric closely related species are discussed.

Host plant selection of five Yponomeuta species was studied in leaf discs tests. Y. cagnagellus showed an absolute preference for Euonymus europaeus, whereas larvae of the other species, in various degrees, proved to be less restricted in their choice. In some instances e.g., of Y. padellus (from Crataegus monogyna), developmental success is greater on Prunus spinosa than on the usual host. The thesis is developed that these observations may be explained by the persistence of previous habits from earlier stages of evolutionary development. RÉSUMÉ PRÉFÉRENCE EN MATIÈRE DE PLANTE‐HÔTE CHEZ CINQ ESPÈCES D'YPONOMEUTES (LEPIDOPTERA: YPONOMEUTIDAE) Le choix de la plante‐hôte chez cinq espèces d'Yponomeuta a été étudié dans des essais utilisant des disques de feuilles. Y. cagnagellus a montré une préférence absolue pour Euonymus europaeus, tandis que les larves des autres espèces, à des degrés divers, se sont montrées moins restrictives dans leur choix. Dans certains cas, par exemple chez Y. padellus (provenant de Crataegus monogyna), le succès du développement est plus grand sur Prunus spinosa que sur son hôte habituel. On émet l'hypothèse que ces observations pourraient refléter une association antérieure de l'insecte avec l'hôte inhabituel au cours de l'évolution du genre.