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- Junker, Robert R., et al.
(författare)
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Covariation and phenotypic integration in chemical communication displays : Biosynthetic constraints and eco-evolutionary implications
- 2018
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 220:3, s. 739-749
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Tidskriftsartikel (refereegranskat)abstract
- Chemical communication is ubiquitous. The identification of conserved structural elements in visual and acoustic communication is well established, but comparable information on chemical communication displays (CCDs) is lacking. We assessed the phenotypic integration of CCDs in a meta-analysis to characterize patterns of covariation in CCDs and identified functional or biosynthetically constrained modules. Poorly integrated plant CCDs (i.e. low covariation between scent compounds) support the notion that plants often utilize one or few key compounds to repel antagonists or to attract pollinators and enemies of herbivores. Animal CCDs (mostly insect pheromones) were usually more integrated than those of plants (i.e. stronger covariation), suggesting that animals communicate via fixed proportions among compounds. Both plant and animal CCDs were composed of modules, which are groups of strongly covarying compounds. Biosynthetic similarity of compounds revealed biosynthetic constraints in the covariation patterns of plant CCDs. We provide a novel perspective on chemical communication and a basis for future investigations on structural properties of CCDs. This will facilitate identifying modules and biosynthetic constraints that may affect the outcome of selection and thus provide a predictive framework for evolutionary trajectories of CCDs in plants and animals.
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| 2. |
- Borchsenius, Finn, et al.
(författare)
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Reproductive isolation of sympatric forms of the understorey palm Geonoma macrostachys in western Amazonia
- 2016
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Ingår i: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074. ; 182:2, s. 398-410
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Tidskriftsartikel (refereegranskat)abstract
- The evolution of a mechanism for attaining reproductive isolation between two diverging populations is a key step in the speciation process. We studied phenotypic variation, genetic differentiation, spatial distribution and reproductive ecology in two sympatric forms of the understorey palm Geonoma macrostachys in lowland tropical rainforest in Amazonian Ecuador. The two forms were morphologically and genetically distinct and differed in habitat preference, with one form being confined to moist flood plain habitats and the other occurring in terra firme and flood plain. Pollen transfer between the two forms was limited, but not totally prevented, by differences in flowering time, with flowers of the small form opening 2–3 h earlier than those of the large form. Differences in floral scent probably reduce the number of shared pollinators. A crossing experiment showed that pistillate flowers of either form produced fruit with pollen from the other form. We conclude that flowering biology may be a key factor in causing reproductive isolation between these closely related sympatric taxa.
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| 5. |
- Roubik, David W., et al.
(författare)
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An embellishment that became a mutualism : Inquiries on male bee tibial bouquets and fragrance-producing orchids in Panama and oceanic islands (Apidae: Apinae, Euglossini; Orchidaceae: Epidendroideae)
- 2017
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Ingår i: Flora. - : Elsevier BV. - 0367-2530. ; 232, s. 117-127
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Tidskriftsartikel (refereegranskat)abstract
- We used comparative studies to investigate how and why floral and bee fragrances evolve, including courtship odors collected by male Euglossa mixta to form their tibial bouquet, on Coiba Island and other Panama forests. Fragrances of four orchid genera, two used extensively by E. mixta - Coryanthes and Mormodes - and two never used, Clowesia and Catasetum - were also analyzed. From among 636 chemicals in 93 male tibiae, 66 were also found in 30 floral head-space samples of orchids, in which 315 total volatile compounds were detected. Geographic variation was noteworthy in E. mixta, but no significant difference was found between mainland and island populations. The aromatic benzenoids methyl salicylate, 2-hydroxy-6-nona-1,3-dienylbenzaldehyde (HNDB), and the monoterpene 1,8 cineole, nearly always occurred. Coryanthes or other orchids produce two of the chemicals, but no source of HNDB is known. No statistical evidence was found of bee preference for orchids with bouquets like those formed in bee hindlegs, yet Coryanthes and Mormodes produced the most monoterpenes and more resembled the bees, when compared to Catasetum and Clowesia. Coiba bee tibial bouquets averaged 56% as diverse as on mainland and Coiba has <50% the euglossine species of nearby mainland, but lacks those most similar to E. mixta, both in phylogeny and tibial bouquet. Coiba's diverse rain forest should contain many volatiles the bees seek. Because odor collection and production are costly, our findings strengthen hypotheses that odors are used to avoid interspecific reproductive interference. Despite finding large differences in the same orchid species, we do not know whether isolation of between 107 and 104 years produced differentiation. Fragrances seem analogous among orchids and bees, thus may lessen interspecific interference or competition, and promote outcrossing or favor embellishments, via female choice. Such adaptive reasons for fragrance variation within bee or orchid populations remain largely untested.
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