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| 2. |
- Forsman, Anders, et al.
(author)
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Evidence for echolocation in the common shrew, Sorex araneus L
- 1988
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In: Journal of Zoology. - : Wiley. - 0952-8369 .- 1469-7998. ; 216, s. 655-662
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Journal article (peer-reviewed)abstract
- In this laboratory experiment it is shown that, like four North American soricid shrew species, the European common shrew Sorex araneus L. is able to use echolocation to identify open and closed tubes at a distance of 200 mm.Three common shrews captured in Sweden were used for the experiments, which were carried out in darkness and within a sound-proof box. The experimental set-up eliminated orientation using sight, sound or scent from outside the experimental cage. Echolocation calls consisted of broadband ultrasonic clicks at low sound pressure. These were recorded using an ultrasound detector.The ecological significance of echolocation in shrews is discussed. It is proposed that common shrews use echolocation to locate protective cover, thus minimizing the risk to be taken by, e.g. owls.Echolocation may also be used for detecting obstacles in subterranean tunnels. Hence, echolocation could be of certain importance when abandoned burrows in the periphery of the tunnel system are restored during periods of increasing population densities. Since density peaks in most populations occur regularly each summer, and may reach extreme magnitudes in cyclic populations, the ecological significance of echolocation in shrews may be considerable.
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| 3. |
- Hovmark, A, et al.
(author)
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First isolations of Borrelia burgdorferi from rodents collected in Northern Europe
- 1988
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In: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley. - 0903-4641 .- 1600-0463. ; 96, s. 917-920
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Journal article (peer-reviewed)abstract
- Spirochetes were found in 13% of Ixodes ricinus collected from an island, near Stockholm where human borreliosis is endemic. Borrelia burgdorferi was cultivated from the kidney and/or spleen of wild rodents (Clethrionomys glareolus and Apodemus flavicollis) from the same island. Spirochetes were identified as Borrelia burgdorferi by indirect immunofluorescence assays using species and genus specific monoclonal antibodies. In these tests the spirochetes could not be differentiated from strains previously cultured from Swedish patients with Ixodes-borne borreliosis. The results show that small rodents in Europe may harbour borreliae and indicate that C. glareolus and A. flavicollis may be important reservoirs for the spirochetes causing Ixodes-borne borreliosis in humans and domestic animals in Europe.
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| 4. |
- Forsman, Anders, et al.
(author)
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Maintenance of colour polymorphism in adder populations, Vipera berus L.: a test of a popular hypothesis
- 1987
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In: Oikos. ; 50, s. 13-16
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Journal article (peer-reviewed)abstract
- Accordingt o a currenth ypothesis,t he colourp olymorphismin populationso f the adder,Vipera berus L., is maintained by a thermal superiority of melanistic snakes,which enables them to grow more quickly than normally coloured ones. Since largermales are superior in sexual combats, and larger females get more offspring, thisclearly should favour the melanistic trait. On the other hand, melanistic individualsare believed to suffer a higher predation pressure due to their more conspicuous appearance.T he predictionf rom this hypothesisi s that melanistici ndividualso n averageshould be largert han normali ndividualsi n mixed populations.T his predictionwas tested on adders captured on several small islands in the Stockholm archipelago(N 59°20';E 19°20').N o significantd ifferencew as found in weight, lengtho r weight/length ratio between melanistic and normally coloured male adders. Neither slopenor elevation of the regression lines of length on weight differed. Thus, the hypothesiswas not supported by our data.
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| 5. |
- Hansson, Bill S., et al.
(author)
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Z‐linked inheritance of male olfactory response to sex pheromone components in two species of tortricid moths, Ctenopseustis obliquana and Ctenopseustis sp
- 1989
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In: Entomologia Experimentalis et Applicata. - : Wiley. - 0013-8703. ; 53:2, s. 137-145
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Journal article (peer-reviewed)abstract
- The olfactory response from male pheromone sensitive sensilla was investigated in the endemic New Zealand brownheaded leafrollers Ctenopseustis obliquana (Walker) and C. sp. ‘ropeana' (Lepidoptera, Tortricidae). The responses from 281 sensilla from the parental strains and from both the reciprocal crosses, including F1, F2 and maternal and paternal backcrosses were recorded, and statistically analysed using a multivariate analysis. In males of both the parental strains, a large amplitude cell responded to the main pheromone component of the conspecific female, in C. obliquana (Z)‐8‐tetradecenyl acetate (Z8–14:OAc) and in C. sp ‘ropeana' (Z)‐5‐tetradecenyl acetate (Z5–14:OAc). Both male types also possessed a small amplitude cell, which in C. obliquana responded weakly to Z5–14: OAc and tetradecyl acetate (14: OAc), and in C. sp ‘ropeana' responded to Z8–14: OAc. The responses from the different types of hybrid males were more variable than the responses from parental males. A main pattern could, however be seen, corresponding with the expected pattern in a sex‐linked inheritance on the Z‐chromosome of a C. sp ‘ropeana' type dominant genetic factor. The more pronounced variation in the hybrids could not be explained by this model, and might be due to the involvement of additional genes. Liaison avec le chromosome Z de l'hérédité des réponses olfactives à la composition de la phéromone sexuelle chez deux tordeuses: Ctenopseustis obliquana et C. sp. ‘ropeana' Les réactions olfactives des sensilles mâles sensibles aux phéromones ont été examinées par enregistrement de l'extrémité de la sensille chez les tordeuses C. obliquana Walker et C. sp. ‘ropeana'. Les enregistrements ont porté sur 281 sensilles des lignées parentales et des croisements réciproques de F1, F2 et de croisements en retour maternel et paternel. Les résultats des enregistrements d'une sensille ont été soumis à une analyse en composantes principales. Chez les mâles de chaque lignée parentale un seul type physiologique de sensille a été découvert; une cellule répond par un pic grand au principal constituant de la phéromone femelle conspécifïque. (Z)‐8‐acétate tétradécényl (Z8–14:OAc) pour C. obliquana, et (Z)‐5‐acétate tétradécényl (Z5–14:OAc) pour C. sp. ‘ropeana'. Une seconde type de cellule dans les sensilles des deux espèces de mâles présente un pic petit pour Z5–14: OAc et pour l'acétate tétradécyl (14: OAc) chez C. obliquana, et pour C. sp. ‘ropeana' au Z8–14:OAc. Les réponses des sensilles des différents types de mâles hybrides sont plus hétérogènes que celles des sensilles de leurs pères. Un schéma général pourrait cependant être décelé, correspondant au schéma prévu avec une hérédité d'un facteur dominant liée au sexe sur le chromosome Z de C. sp. ‘ropeana’. La variation plus accentuée chez les hybrides ne peut être expliquée par ce modèle, et pourrait impliquer des gènes additionnels. 1989 The Netherlands Entomological Society
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| 6. |
- Lofstedt, Christer, et al.
(author)
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Pheromone dialects in European turnip moths Agrotis segetum
- 1986
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In: Oikos. - : JSTOR. - 0030-1299. ; 46:2, s. 250-257
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Journal article (peer-reviewed)abstract
- Female pheromone gland extracts from cultures of Agrotis segetum originating from Sweden, France, Hungary and England were analysed for pheromone components and precursors (fatty acids). The pheromone blends were similar in moths from the Swedish, English and Hungarian populations, whereas the French diverged with a much higher amount of (Z)-7-decenyl acetate relative to the homologous pheromone components (Z)-7-dodecenyl acetate and (Z)-9-tetradecenyl acetate. -from Authors
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| 7. |
- Löfstedt, Christer, et al.
(author)
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Evolution of the ermine moth pheromone tetradecyl acetate
- 1986
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In: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 323:6089, s. 621-623
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Journal article (peer-reviewed)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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| 8. |
- Löfstedt, Christer, et al.
(author)
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Individual variation in the pheromone of the turnip moth, Agrotis segetum
- 1985
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In: Journal of Chemical Ecology. - 0098-0331. ; 11:9, s. 1181-1196
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Journal article (peer-reviewed)abstract
- Female turnip moths (Agrotis segetum) from a laboratory culture inbred for more than 30 generations, and the offspring (first and third generation) from field-collected insects were analyzed individually for acetates and alcohols in the pheromone gland. Quantitative analysis of individual components was performed at the subnanogram level by gas chromatographymass spectrometry (selected ion monitoring). The titer of the pheromone, i.e., the sum of the homologous acetates (Z)-5-decenyl acetate, (Z)-7-dodecenyl acetate, and (Z)-9-tetradecenyl acetate was 2.0 ± 0.3 ng in the laboratory culture and 3.2 ± 0.6 ng in the "wild strain." There was no correlation between pheromone titer and female weight. The relative proportion of the pheromone components varied substantially between individuals, but there was no statistically significant difference between the two populations. The percentages of the respective compounds (-X ± coefficient of variation) were 14.8 ± 127% for Z5-10:OAc, 55.6 ± 32% for Z7-12:OAc, and 29.6 ± 59% for Z9-14:OAc. The pheromone composition varied more in the wild strain than in the laboratory culture. The significance of the pheromone variation to the attraction of males was tested in a field experiment. The ratio of males trapped by the most attractive blend versus the least attractive one was 2.2.
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| 9. |
- Löfstedt, Christer, et al.
(author)
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Sex pheromones and reproductive isolation in four european small ermine moths
- 1985
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In: Journal of Chemical Ecology. - 0098-0331. ; 11:5, s. 649-666
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Journal article (peer-reviewed)abstract
- Reproductive isolation among four sympatric small ermine moths (Yponomeuta) is analyzed in terms of niches in the sexual communication channel. Potential pheromone components were identified from pheromone gland secretions of Y. evonymellus, Y. cagnagellus, Y. padelius, and Y. vigintipunctatus by gas chromatography with flame ionization and electroantennographic detection and tested for behavioral activity in the field. The species were found to share (Z)-11-tetradecenyl acetate (Z11-14: OAc) in combination with varying proportions of the E isomer as primary sex pheromone components. Y. cagnagellus differs from the rest of the species by having only a small amount (1.5%) of E isomer relative to Z isomer in its pheromone. The closely related Y. padelius has a three-component pheromone including large amounts (ca. 400%) of (Z)-11-hexadecenyl acetate (Z11-16:OAc) in addition to Z11-14: OAc (100%) and E11-14: OAc (34%). Z11-16: OAc appears to reduce trap catches of Y. evonymellus and Y. vigintipunctatus when added to the pheromone. Although these species are the two most distantly related European small ermine moths, they seem to share the same sex pheromone, i.e., Z11-14:OAc (+20%E) and (Z)-11-tetradecenol. Our interpretation is that this might have been the sex pheromone of the ancestor of today's Yponomeuta species.
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| 10. |
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