| 1. |
- Sköld, Helen Nilsson, et al.
(författare)
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Hormonal regulation of female nuptial coloration in a fish.
- 2008
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Ingår i: Hormones and behavior. - : Elsevier BV. - 1095-6867 .- 0018-506X. ; 54:4, s. 549-56
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Tidskriftsartikel (refereegranskat)abstract
- Physiological color change in camouflage and mating is widespread among fishes, but little is known about the regulation of such temporal changes in nuptial coloration and particularly concerning female coloration. To better understand regulation of nuptial coloration we investigated physiological color change in female two-spotted gobies (Gobiusculus flavescens). Females of this species develop an orange belly that acts as an ornament. The orange color is caused by the color of the gonads combined with the chromathophore based pigmentation and transparency of the skin. Often during courtship and female-female competition, a rapid increase in orange coloration, in combination with lighter sides and back that increases skin and body transparency, gives the belly an intense 'glowing' appearance. To understand how this increased orange coloration can be regulated we analysed chromatic and transparency effects of neurohumoral agents on abdominal skin biopsies in vitro. We found prolactin and alpha-melanocyte stimulating hormone (MSH) to increase orange coloration of the skin. By contrast, melatonin and noradrenaline increased skin transparency, but had a negative effect on orange coloration. However, mixtures of melatonin and MSH, or melatonin and prolactin, increased both orange coloration and transparency. This effect mimics the chromatic 'glow' effect that commonly takes place during courtship and intra sexual aggression. Notably, not only epidermal chromatophores but also internal chromatophores lining the peritoneum responded to hormone treatments. There were no chromatic effects of the sex steroids 17beta-estradiol, testosterone or 11-ketotestosterone. We hypothesize that similar modulation of nuptial coloration by multiple hormones may be widespread in nature.
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| 2. |
- Schneider, Nicole, et al.
(författare)
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Influence and value of different water regimes on avian species richness in arid inland Australia
- 2009
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Ingår i: Biodiversity and Conservation. - : Springer Science and Business Media LLC. - 0960-3115 .- 1572-9710. ; 18:2, s. 457-471
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Tidskriftsartikel (refereegranskat)abstract
- Riparian habitats in arid landscapes are recognised for their structurally diverse vegetation and diverse bird species assemblages. In the extensive semi-arid and arid centre of Australia, riparian woodland habitats are impacted by pastoral land-use which may negatively influence vegetation structure and avian species composition. However, pastoralism has promoted the establishment of artificial water bodies, so that additional riparian vegetation may occur in the landscape. In this study, we surveyed the importance of different water regimes (i.e. artificial lakes, natural waterholes, desert sites) together with their associated vegetation on avian species richness in north-western New South Wales, Australia. Our results show that bird species richness was highest at water locations, in particular at artificial lakes. Avian species richness was negatively associated with distance to water bodies, both in desert vegetation types and in the riparian vegetation type along dry creeks. Moreover, riparian habitats supported larger avian assemblages and especially those of sedentary bird species compared to the surrounding shrub-steppe landscape. This indicates that artificial water bodies may be of significance for arid zone bird species and might gain in importance with changing water availabilities due to climatic changes.
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| 3. |
- Nilsson, R. Henrik, 1976, et al.
(författare)
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Intraspecific ITS Variability in the Kingdom Fungi as Expressed in the International Sequence Databases and Its Implications for Molecular Species Identification
- 2008
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Ingår i: Evolutionary Bioinformatics. - 1176-9343. ; 2008:4, s. 193-201
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Tidskriftsartikel (refereegranskat)abstract
- The internal transcribed spacer (ITS) region of the nuclear ribosomal repeat unit is the most popular locus for species identification and subgeneric phylogenetic inference in sequencebased mycological research. The region is known to show certain variability even within species, although its intraspecific variability is often held to be limited and clearly separated from interspecific variability. The existence of such a divide between intra and interspecific variability is implicitly assumed by automated approaches to species identification, but whether intraspecific variability indeed is negligible within the fungal kingdom remains contentious. The present study estimates the intraspecific ITS variability in all fungi presently available to the mycological community through the international sequence databases. Substantial differences were found within the kingdom, and the results are not easily correlated to the taxonomic affiliation or nutritional mode of the taxa considered. No single unifying yet stringent upper limit for intraspecific variability, such as the canonical 3 % threshold, appears to be applicable with the desired outcome throughout the fungi. Our results caution against simplified approaches to automated ITSbased species delimitation and reiterate the need for taxonomic expertise in the translation of sequence data into species names.
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| 4. |
- Lundberg, Magnus, 1976-, et al.
(författare)
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Allopolyploidy in Fragariinae (Rosaceae): Comparing four DNA sequence regions, with comments on classification
- 2009
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Ingår i: Molecular phylogenetics and evolution. - : Elsevier BV. - 1055-7903 .- 1095-9513. ; 51, s. 269-280
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Tidskriftsartikel (refereegranskat)abstract
- Potential events of allopolyploidy may be indicated by incongruences between separate phylogenies based on plastid and nuclear gene sequences. We sequenced two plastid regions and two nuclear ribosomal regions for 34 ingroup taxa in Fragariinae (Rosaceae), and six outgroup taxa. We found five well supported incongruences that might indicate allopolyploidy events. The incongruences involved Aphanes arvensis, Potentilla miyabei, Potentilla cuneata, Fragaria vesca/moschata, and the Drymocallis clade. We evaluated the strength of conflict and conclude that allopolyploidy may be hypothesised in the four first cases. Phylogenies were estimated using Bayesian inference and analyses were evaluated using convergence diagnostics. Taxonomic implications are discussed for genera such as Alchemilla, Sibbaldianthe, Chamaerhodos, Drymocallis and Fragaria, and for the monospecific Sibbaldiopsis and Potaninia that are nested inside other genera. Two orphan Potentilla species, P. miyabei and P. cuneata are placed in Fragariinae. However, due to unresolved topological incongruences they are not reclassified in any genus.
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| 5. |
- Wedin, Mats, et al.
(författare)
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Slippery when wet: Phylogeny and character evolution in the gelatinous cyanobacterial lichens (Peltigerales, Ascomycetes)
- 2009
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Ingår i: Molecular Phylogenetics and Evolution. - San Diego : Elsevier BV. - 1055-7903 .- 1095-9513. ; 53:3, s. 862-871
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Tidskriftsartikel (refereegranskat)abstract
- Many lichen fungi form symbioses with filamentous Nostoc cyanobacteria, which cause the lichen toswell and become extremely gelatinous when moist. Within the Lecanoromycetes, such gelatinous lichens are today mainly classified in the Collemataceae (Peltigerales, Ascomycota). We performed Bayesian MCMC, maximum likelihood, and maximum parsimony analyses of three independent markers(mtSSU rDNA, nuLSU rDNA, and RPB1), to improve our understanding of the phylogeny and classification in the Peltigerales, as well as the evolution of morphological characters that have been used for classification purposes in this group. The Collemataceae and the non-gelatinous Pannariaceae are paraphyleticbut can be re-circumscribed as monophyletic if Leciophysma, Physma, Ramalodium and Staurolemma are transferred to the Pannariaceae. The gelatinous taxa transferred to the Pannariaceae deviate from other Collemataceae in having simple ascospores, and several also have a ring-shaped exciple as in other Pannariaceae, rather than the disc-shaped exciple found in the typical Collemataceae. Both Collema and Leptogium are non-monophyletic. The re-circumscribed Collemataceae shares a distinct ascus type withthe sister group Placynthiaceae and the Coccocarpiaceae, whereas Pannariaceae includes a variety of structures. All Pannariaceae have one-celled ascospores, whereas all Collemataceae have two- or multi-celled spores. Reconstructions of the number of character state transformations in exciple structure, thallus gelatinosity, and ascus apex structure indicate that the number of transformations is distinctly higher than the minimum possible. Most state transformations in the exciple took place from aring-shaped to a disc-shaped exciple. Depending on the reconstruction method, most or all transformationsin thallus structure took place from a non-gelatinous to a gelatinous thallus. Gains and losses of internal structures in the ascus apex account for all or a vast majority of the number of transformations in the ascus, whereas direct transformations between asci with internal structures appear to have been rare.
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| 6. |
- Svensson, P. A., et al.
(författare)
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Chromatic interaction between egg pigmentation and skin chromatophores in the nuptial coloration of female two-spotted gobies
- 2005
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Ingår i: Journal of Experimental Biology. - : The Company of Biologists. - 0022-0949 .- 1477-9145. ; 208:23, s. 4391-4397
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Tidskriftsartikel (refereegranskat)abstract
- In two-spotted gobies (Gobiusculus flavescens Fabricius 1779), females develop an orange belly as they approach sexual maturity. Bright belly coloration is preferred by males and has been suggested to act as a female ornament. This coloration is unusual in that it originates partly from pigmentation of the abdominal skin but also from strongly pigmented gonads directly visible through the skin. In addition, females have been observed to temporarily become more colourful during courtship and competition. To understand how gonad and skin pigmentation interact in this nuptial coloration, the potential for colour modification via regulation of skin chromatophores was investigated. Noradrenaline caused aggregation of chromatophore pigment and was used to experimentally reduce the contribution of skin chromatophores to the nuptial coloration. Chromatophore pigment aggregation caused bellies to become less colourful and abdominal skin biopsies to become less colourful and more transparent. There was a strong positive relationship between belly coloration and the coloration of the underlying gonads. This shows that belly coloration honestly reflects egg pigmentation, mainly because the transparency of the abdominal skin allows other fish to see the gonads directly. Interestingly, when noradrenaline caused pigment to aggregate and thereby increased the transparency of the skin, the relationship between belly and gonad coloration weakened. We conclude that female G. flavescens have a potential to use skin chromatophores to rapidly alter their nuptial coloration, thereby affecting the efficacy with which information about gonad coloration is conveyed.
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| 7. |
- Koch, Kamilla, et al.
(författare)
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Morphological differences in the ovary of Libellulidae (Odonata)
- 2009
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Ingår i: International Journal of Odonatology. - Oxford : Taylor & Francis. - 1388-7890 .- 2159-6719. ; 12:1, s. 147-156
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Tidskriftsartikel (refereegranskat)abstract
- All female Odonata have been assumed to produce oocytes continuously during their mature life span. However, a recent study of ovariole orientation and development led to the suggestion that Libellulidae are divided into two groups of species, one with continuous, the other with stepwise oocyte production. To find more evidence of this division, we compared the size variation and growth within the vitellarium of the ovary, studying oocytes, and follicle cells. We found that morphological characters discriminate between the two ovary types in eight of the 10 investigated species. In both types we found an increase in all measurements from the anterior to the posterior end of the vitellarium. The increase in oocyte width and follicle cell length was significantly higher in species with a continuous oocyte production. We also noted that follicle cells may have more than one nucleus and that their number can vary during vitellogenesis. Our study confirmed the hypotheses that two different ovary types exist in Libellulidae. The two species not fitting into this grouping could be an artefact of small samp le size due to intraspecific phenotypic plasticity, or else there might be more than two ovary groups, or even a continuum. We could not offer an explanation as to how the process of stepwise oocyte production differs from continuous based production on morphological characters.
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| 8. |
- Uller, Tobias, 1977, et al.
(författare)
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Direct exposure to corticosterone during embryonic development influences behaviour in an ovoviviparous lizard
- 2006
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Ingår i: ETHOLOGY. - : Wiley. - 0179-1613 .- 1439-0310. ; 112:4, s. 390-397
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Tidskriftsartikel (refereegranskat)abstract
- It is becoming increasingly clear that conditions experienced during embryonic development can be of major importance for traits subsequent to parturition or hatching. For example, in mammals, offspring from stressed mothers show a variety of changes in behavioural, morphological, and life-history traits. The effects of maternal stress on trait development are believed to be mediated via transfer of glucocorticoids, the main hormones released during the stress response, from mother to offspring. However, also other physiological maternal responses during stress could be responsible for changes in offspring phenotype. We investigated the direct effects of corticosterone on offspring development, without other confounding factors related to increased maternal stress, by injection of corticosterone in eggs of the ovoviviparous lizard Lacerta vivipara. Corticosterone-manipulated offspring did not show impaired development, reduced body size or body condition at parturition. However, corticosterone-treated offspring showed altered anti-predator behaviour, as measured by the time required to emerge from shelter after a simulated predator attack. Differential steroid exposure during development, possibly mediated by maternal stress response, may explain some of the variation in behaviour among individuals in natural populations.
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| 9. |
- Antonelli, Alexandre, 1978, et al.
(författare)
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Pollination of the Lady's slipper orchid (Cypripedium calceolus) in Scandinavia - taxonomic and conservational aspects
- 2009
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Ingår i: Nordic Journal of Botany. - : Wiley. - 0107-055X .- 1756-1051. ; 27:4, s. 266-273
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Tidskriftsartikel (refereegranskat)abstract
- The Lady's slipper orchid Cypripedium calceolus L. is considered one of the most beautiful orchids of Europe. Consequently, the species has suffered from over-collecting and is now critically endangered in many countries. Although pollination success is suspected to influence the long-term survival of Cypripedium calceolus, relatively little is known about the identity of its pollinators in mainland Sweden - a region that comprises the largest European populations. In order to identify which species pollinate eight representative populations in mainland Sweden, we observed and sampled visitors to flowers using a standardized protocol. Specimens were identified and any pollen smear found on their body was examined for the presence of Cypripedium pollen. Nine species were recognized as effective pollen vectors (Andrena cineraria, A. carantonica, A. haemorrohoa, A. helvola, A. nigroaenea, A. praecox, Colletes cunicularius, Lasioglossum fratellum and L. fulvicorne), four of them for the first time in Scandinavia. This is the first time that a species of Colletes is reported to carry pollen of Cypripedium in this region. All but one specimens were females. Our results suggest a taxonomically heterogeneous pollinator fauna for Cypripedium calceolus and are discussed in light of the management of this species.
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| 10. |
- Antonelli, Alexandre, 1978, et al.
(författare)
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Tracing the impact of the Andean uplift on Neotropical plant evolution
- 2009
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424. ; 106:24, s. 9749-9754
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Tidskriftsartikel (refereegranskat)abstract
- Recent phylogenetic studies have revealed the major role played by the uplift of the Andes in the extraordinary diversification of the Neotropical flora. These studies, however, have typically considered the Andean uplift as a single, time-limited event fostering the evolution of highland elements. This contrasts with geological reconstructions indicating that the uplift occurred in discrete periods from west to east and that it affected different regions at different times. We introduce an approach for integrating Andean tectonics with biogeographic reconstructions of Neotropical plants, using the coffee family (Rubiaceae) as a model group. The distribution of this family spans highland and montane habitats as well as tropical lowlands of Central and South America, thus offering a unique opportunity to study the influence of the Andean uplift on the entire Neotropical flora. Our results suggest that the Rubiaceae originated in the Paleotropics and used the boreotropical connection to reach South America. The biogeographic patterns found corroborate the existence of a long-lasting dispersal barrier between the Northern and Central Andes, the "Western Andean Portal.'' The uplift of the Eastern Cordillera ended this barrier, allowing dispersal of boreotropical lineages to the South, but gave rise to a huge wetland system ("Lake Pebas'') in western Amazonia that prevented in situ speciation and floristic dispersal between the Andes and Amazonia for at least 6 million years. Here, we provide evidence of these events in plants.
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