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| 2. |
- Bengtsson, Marie, et al.
(författare)
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Pheromone races of Cydia splendana (Lepidoptera, Tortricidae) overlap in host plant association and geographic distribution
- 2014
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media S.A.. - 2296-701X. ; 2, s. 1-6
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Tidskriftsartikel (refereegranskat)abstract
- Identification of the sex pheromone of Cydia splendana (Lepidoptera, Tortricidae) bypheromone gland analysis followed by field trapping with synthetic compounds showsthe occurrence of two pheromone races. Acorn moth females from Sweden, whereoak Quercus robur is the only host plant, use a blend of the E,Z and E,E isomers of8,10-dodecadien-1-yl acetate. In Central and Southern Europe, where C. splendana feedson chestnut Castanea sativa and several species of oak, males respond to another isomerblend, E,E and Z,E. The distribution of the two pheromone races of C. splendana overlapsin Northern France, where they share oak as plant host. Differences in sex communicationsignals between these populations of C. splendana corroborate the role of specific materecognition in speciation events.
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| 3. |
- Koutroumpa, Fotini A, et al.
(författare)
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Shifts in sensory neuron identity parallel differences in pheromone preference in the European corn borer
- 2014
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 2, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- Pheromone communication relies on highly specific signals sent and received between members of the same species. However, how pheromone specificity is determined in moth olfactory circuits remains unknown. Here we provide the first glimpse into the mechanism that generates this specificity in Ostrinia nubilalis. In Ostrinia nubilalis it was found that a single locus causes strain-specific, diametrically opposed preferences for a 2-component pheromone blend. Previously we found pheromone preference to be correlated with the strain and hybrid-specific relative antennal response to both pheromone components. This led to the current study, in which we detail the underlying mechanism of this differential response, through chemotopically mapping of the pheromone detection circuit in the antenna. We determined that both strains and their hybrids have swapped the neuronal identity of the pheromone-sensitive neurons co-housed within a single sensillum. Furthermore, neurons that mediate behavioral antagonism surprisingly co-express up to five pheromone receptors, mirroring the concordantly broad tuning to heterospecific pheromones. This appears as possible evolutionary adaptation that could prevent cross attraction to a range of heterospecific signals, while keeping the pheromone detection system to its simplest tripartite setup.
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| 4. |
- Linderholm, Hans W., 1968, et al.
(författare)
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Growth dynamics of tree-line and lake-shore Scots pine (Pinus sylvestris L.) in the central Scandinavian Mountains during the Medieval Climate Anomaly and the early Little Ice Age
- 2014
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Trees growing at their altitudinal or latitudinal distribution in Fennoscandia have been widely used to reconstruct warm season temperatures, and the region hosts some of the world’s longest tree-ring chronologies. These multi-millennial long chronologies have mainly been built from tree remains found in lakes (subfossil wood from lake-shore trees). We used a unique dataset of Scots pine tree-ring data collected from wood remains found on a mountain slope in the central Scandinavian Mountains, yielding a chronology spanning over much of the last 1200 years. This data was compared with a local subfossil wood chronology with the aim to 1) describe growth variability in two environments during the Medieval Climate Anomaly (MCA) and the early Little Ice Age (LIA), and 2) investigate differences in growth characteristics during these contrasting periods. It was shown that the local tree-line during both the MCA and early LIA was almost 150 m higher that at present. Based on living pines from the two environments, tree-line pine growth was strongly associated with mid-summer temperatures, while the lake-shore trees showed an additional response to summer precipitation. During the MCA, regarded to be a period of favourable climate in the region, the tree-ring data from both environments showed strong coherency and moderate growth variability. In the early LIA, the two chronologies were less coherent, with the tree-line chronology showing more variability, suggesting different growth responses in the two environments during this period of less favourable growing conditions. Our results indicate that tree-ring width chronologies mainly based on lake-shore trees may need to be reevaluated.
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| 5. |
- Saveer, Ahmed, et al.
(författare)
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Mate recognition and reproductive isolation in the sibling species Spodoptera littoralis and Spodoptera litura
- 2014
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Ingår i: Frontiers in Ecology and Evolution. - : Frontiers Media SA. - 2296-701X. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Mate recognition is crucial for reproductive isolation and for maintaining species integrity. Chemosensory-mediated sexual communication with pheromones is an essential component of mate recognition in moths. Confronted with sex pheromone stimuli released from conspecific and closely related heterospecific females, which partially overlap in chemical composition, male moths are under strong selection to recognize compatible mates. Here, we investigated the role of pheromone signals in premating communication in the sibling species Spodoptera littoralis and S. litura (Lepidoptera, Noctuidae). Further, we measured the reproductive consequence of conspecific vs. heterospecific matings. Both species use Z9,E11–14:Ac as the major pheromone compound, and the 11-component blend found in pheromone glands of S. littoralis comprises the compounds found in S. litura. Accordingly, S. littoralis and S. litura males readily responded to conspecific and heterospecific calling females in no-choice behavioral tests. In contrast, in a dual-choice test, S. littoralis males choose conspecific calling females, whereas S. litura males did not discriminate between conspecific and heterospecific females. In S. littoralis females, heterospecific matings had a negative fitness effect as compared to conspecific matings. Female longevity, egg-laying and hatching of larvae were significantly reduced by matings with heterospecific males. Reciprocal crossings, between S. litura females and S. littoralis males, were prevented by genital morphology, which is consistent with reduced heterospecific attraction of S. littoralis males in a dual-choice assay. On the other hand, matings between S. littoralis females and S. litura males, under a no-choice situation, show that interspecific matings occur in zones of geographical overlap and corroborate the idea that mate quality, in these closely related species, is a continuous and not a categorical trait.
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