| 1. |
- Löfstedt, Christer, et al.
(författare)
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Behavioural and electrophysiological activity of unsaturated analogues of the pheromone tetradecyl acetate in the small ermine moth Yponomeuta rorellus
- 1990
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Ingår i: Physiological Entomology. - : Wiley. - 0307-6962 .- 1365-3032. ; 15:1, s. 47-54
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Tidskriftsartikel (refereegranskat)abstract
- ABSTRACT 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.
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| 2. |
- Löfstedt, Christer, et al.
(författare)
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Evolution of the ermine moth pheromone tetradecyl acetate
- 1986
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 323:6089, s. 621-623
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Tidskriftsartikel (refereegranskat)abstract
- The nine sympatric forms of small ermine moths of the genus Yponomeuta (Lepidoptere; Yponomeutidae) in the west palaearctic region show various degrees of differentiation1,2, including among other characteristics, differences in their sexual pheromones3. As is the case for many other moths4, the ermine moths so far analysed use delta 11-unsaturated acetates ((Z)-11-tetradecenyl, (E)-11-tetradecenyl and (Z)-11-hexadecenyl acetate) as primary pheromone components. Here for the first time in Lepidoptera we report that a saturated acetate, tetradecyl acetate, is the primary pheromone component5 of Y. rorellus (Hübner). Y. rorellus is almost monomorphic with respect to isoenzyme variation6 and has fewer chromosomes than its relatives7,8. We suggest that it has evolved through loss of unsaturated pheromone components in a 'genetic revolution' at a population bottleneck, and by the founders of the new species filling an empty communication niche, separated from that of the ancestral species.
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| 3. |
- Löfstedt, Christer, et al.
(författare)
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Sex pheromones and their potential role in the evolution of reproductive isolation in small ermine moths (Yponomeutidae)
- 1991
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Ingår i: Chemoecology. - 0937-7409. ; 2:1, s. 20-28
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Tidskriftsartikel (refereegranskat)abstract
- Sex pheromone communication in the nine European species of small ermine moths (Yponomeuta) is reviewed in regard to the potential role of pheromones in the speciation process. Six of the nine species studied (viz., Y. evonymellus, Y. cagnagellus, Y. padellus, Y. irrorellus, Y. plumbellus, and Y. vigintipunctatus) use a mixture of (E)-11-and (Z)-11-tetradecenyl acetate in different ratios as primary pheromone components, with combinations of tetradecyl acetate, (Z)-9-tetradecenyl acetate, (Z)-11-hexadecenyl acetate and the corresponding alcohols of the acetates as additional pheromone components. Analysis of (Z)- to (E)-11-tetradecenyl acetate ratios produced by individual females of these species demonstrated significant variation among females of all species. However, the ranges of ratios produced by Y. cagnagellus, Y. irrorellus, and Y. plumbellus, sharing the same host-plant species, spindle tree, did not overlap. Niche separation of all six species mentioned required consideration of at least one additional pheromone component or of temporal aspects. The remaining three species, i.e. Y. malinellus, Y. mahalebellus and Y. rorellus, have pheromones that differ qualitatively. 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)-11- and (E)-11-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. Pheromone differences within the so-called padellus-complex (including Y. cagnagellus, Y. mahalebellus, Y. malinellus, Y. padellus, and Y. rorellus) in which species might have originated sympatrically, may have evolved by reinforcing selection as these species still hybridise and produce viable offspring when confined in cages. The role of pheromones in reproductive isolation among 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.
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| 4. |
- Löfstedt, Christer, et al.
(författare)
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Sex pheromones of three small ermine moths found on the European spindle tree
- 1988
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Ingår i: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703. ; 46:1, s. 29-38
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Tidskriftsartikel (refereegranskat)abstract
- The sex pheromones produced by virgin females of three species of small ermine moths occurring sympatrically on the European spindle tree were analysed by gas chromatography and the synthetic compounds tested against male moths in the laboratory and field. Pheromone gland extracts of Yponomeuta cagnagellus were shown to contain tetradecyl acetate, (E)‐11‐ and (Z)‐11‐tetradecenyl acetate, tetradecanol, (E)‐11‐ and (Z‐11‐tetradecenol and hexadecyl acetate in 30/3/100/6/0/7/42 ratio. Wind tunnel bioassays and field tests showed that (E)‐11‐ and (Z)‐11‐tetradecenyl acetate primary pheromone components, and that tetradecyl acetate synergised their attractiveness. The alcohols were unimportant in these tests. Analysis of the pheromone gland extracts from Y. irrorellus showed the above components in 68/56/100/9/6/8/17 ratio, and a mixture of these attracted male moths in laboratory and field. Omission of either unsaturated acetate gave unattractive mixtures, and the alcohols were also found to be important for attraction. Pheromone gland extracts from Y. plumbellus were shown to contain the seven components in 46/148/100/20/20/13/25 ratio. Field tests showed that the two monounsaturated acetates are primary pheromone components, and removal of the alcohols had no significant effect. The titre of (Z)‐11‐tetradecenyl acetate in Y. plumbellus pheromone gland extracts was approximately 0.5 ng per female, one tenth the titre in the other two species. It is concluded that mixtures of three or more pheromone components with specific E/Z ratio are essential for full attraction and contribute towards premating reproductive isolation of the three species. Other factors such as rate of pheromone emission, time of flight and height of flight may also contribute to reproductive isolation. Phéromones sexuelles de 3 Yponomeutes trouvés sur fusain (Evonymus europeus) L'analyse a porté sur les phéromones sexuelles de 3 Yponomeutidae, trouvés en sympatrie sur le fusain. Des expériences sur le comportement de Y. cagnagellus ont montré que la fraction acétate de tétradécyl de la phéromone synergise les fractions connues antérieurement: (E)‐11‐ et (Z)‐11‐acétates de tétradécényl, lorsque les proportions sont 37/2/100. L'analyse en chromatographie gazeuse d'extraits de glandes à phéromone de Y. irrorellus a mis en évidence, dans les proportions approximatives suivantes 68/56/100/9/6/8/7, de l'acétate de tétradécyl, des (E)‐11 et (Z)‐11 acétates de tétradécényl, du tétradé‐canol, des (E)‐11 et (Z)‐11‐tétradécénols, et de l'acétate d'hexadécyl. Un mélange de ces composés a provoqué un vol intégral contre le vent des mǎles dans un tunnel à vent et a attiré les mǎles dans la nature. L'analyse des extrait de glandes à phéromone de Y. plumbellus a donné de l'acétate de tétradécyl, du (E)‐11‐acétate de tétradécényl et du (Z)‐11‐acétate de tétradécényl, dans les proportions: 50/150/100. Une étude par élimination dans la nature a montré que les acétates non saturés étaient les composés fondamentaux de la phéromone. La teneur en (Z)‐11‐ acétate de tétradécényl de la glande à phéromone de Y. plumbellus était d'environ 0.5 ng par femelle, soit approximativement le dixième de celle observée chez les deux autres espèces. Une très faible attraction croisée a été trouvée avec des phéromones totalement synthétisées. Lorsque l'acétate de (E)‐11‐ tétradécényl a été enlevé des phéromones de Y. irrorellus et Y. plumbellus, le reliquat a attiré des nombres significatifs de Y. cagnagellus. Nous en concluons que des mélanges de trois composés ou plus, avec des proportions spécifiques des isomères (E) et (Z), sont indispensables pour une activité complète et pour maintenir un isolement reproductif précopulatoire entre les espéces. 1988 The Netherlands Entomological Society
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