Unusual carotenoid use by the Western Tanager (Piranga ludoviciana) and its evolutionary implications

1991 ◽  
Vol 69 (9) ◽  
pp. 2311-2320 ◽  
Author(s):  
Jocelyn Hudon
Keyword(s):  
The Other ◽  
Coniferous Forests ◽  
Close Relative ◽  
Minimal Effect ◽  
Red Pigment ◽  
Western North America ◽  
Reflectance Spectrophotometry ◽  
Endogenous Production ◽  
Selection For ◽  
Morphological Differences

I used spectrophotometric, chromatographic, and chemical means to establish that rhodoxanthin, a 3-keto-retrodehydro carotenoid, was the only red pigment in the head feathers of the Western Tanager (Piranga ludoviciana). In contrast, the red head and body feathers of a close relative, the Scarlet Tanager (P. olivacea), exhibited several 4-keto-carotenoids. Other tanagers and emberizids also displayed 4-keto-carotenoids. The deposition of presumed canary xanthophylls and phaeomelanins differed quantitatively between the Western Tanager and other tanagers belonging to the genus Piranga. Uniquely among the Piranga spp. examined, the head feathers of the Western Tanager had flattened bards without barbules. Partly because the head colors of the Western and Scarlet tanagers were indistinguishable either in the hand or when examined by reflectance spectrophotometry, I excluded selection for a variant color as the basis for the observed chemical and morphological differences. Biochemical costs, including putative costs associated with the endogenous production of 4-keto-carotenoids, could have led to the conversion in the Western Tanager to an available dietary pigment. This tanager, unlike the other species studied, has access to an abundant source of rhodoxanthin in the coniferous forests of western North America. The pigment changes in the Western Tanager could have taken place with minimal effect on head color.

Palynological analysis and taxonomic position of the genus Mertensia (Boraginaceae)

Botany ◽  
2012 ◽  
Vol 90 (8) ◽  
pp. 722-730 ◽  
Author(s):  
Tomoko Fukuda ◽  
Hiroshi Ikeda
Keyword(s):  
North America ◽  
Pollen Grains ◽  
The Other ◽  
Taxonomic Position ◽  
Western North America ◽  
Pollen Type ◽  
Palynological Analysis ◽  
Distinct Genus ◽  
Morphological Differences ◽  
Himalayan Species

Palynological analysis of the genus Mertensia Roth, s. lat. (Boraginaceae) was performed. All pollen grains studied were mostly dumbbell shaped and had 6-heteroaperturate pollen type without exception. The type of pollen of Mertensia does not contradict recent classifications that assign Mertensia to Cynoglosseae. Among six sections of Mertensia, pollen grains of section Oreocharis (the Himalayan Mertensia) were different from those of other sections in having granulate sculpturing on the colpus and pseudocolpus membranes. The results, along with other morphological differences, may support Riedl’s treatment of the Himalayan species of Mertensia in the distinct genus Pseudomertensia Riedl. Of the other sections, four monotypic sections (sections Steenhanmera, Neuranthia, Typomertensia, and Mertensianthe) showed pollen structures similar to each other. Pollen grains in section Eumertensia had some variations in size and ornamentation, especially in the species distributed in western North America.

scholarly journals Long way to Ricci flatness

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
Jin Chen ◽  
Chao-Hsiang Sheu ◽  
Mikhail Shifman ◽  
Gianni Tallarita ◽  
Alexei Yung
Keyword(s):  
Sigma Model ◽  
Ultra Violet ◽  
The Other ◽  
Target Space ◽  
Linear Sigma Model ◽  
Close Relative ◽  
Two Dimensional ◽  
World Sheet ◽  
Ricci Flat ◽  
The World

Abstract We study two-dimensional weighted $$ \mathcal{N} $$ N = (2) supersymmetric ℂℙ models with the goal of exploring their infrared (IR) limit. 𝕎ℂℙ(N,$$ \tilde{N} $$ N ˜ ) are simplified versions of world-sheet theories on non-Abelian strings in four-dimensional $$ \mathcal{N} $$ N = 2 QCD. In the gauged linear sigma model (GLSM) formulation, 𝕎ℂℙ(N,$$ \tilde{N} $$ N ˜ ) has N charges +1 and $$ \tilde{N} $$ N ˜ charges −1 fields. As well-known, at $$ \tilde{N} $$ N ˜ = N this GLSM is conformal. Its target space is believed to be a non-compact Calabi-Yau manifold. We mostly focus on the N = 2 case, then the Calabi-Yau space is a conifold. On the other hand, in the non-linear sigma model (NLSM) formulation the model has ultra-violet logarithms and does not look conformal. Moreover, its metric is not Ricci-flat. We address this puzzle by studying the renormalization group (RG) flow of the model. We show that the metric of NLSM becomes Ricci-flat in the IR. Moreover, it tends to the known metric of the resolved conifold. We also study a close relative of the 𝕎ℂℙ model — the so called zn model — which in actuality represents the world sheet theory on a non-Abelian semilocal string and show that this zn model has similar RG properties.

scholarly journals Inter- and Intra-Continental Genetic Variation in the Generalist Conifer Wood Saprobic Fungus Phlebiopsis gigantea

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 751
Author(s):  
Francesco Dovana ◽  
Paolo Gonthier ◽  
Matteo Garbelotto
Keyword(s):  
North America ◽  
Genetic Differentiation ◽  
Dna Sequences ◽  
North American ◽  
Fungal Species ◽  
Coniferous Forests ◽  
Native Forest ◽  
Western North America ◽  
Phlebiopsis Gigantea ◽  
Conifer Wood

Phlebiopsis gigantea (Fr.) Jülich is a well-known generalist conifer wood saprobe and a biocontrol fungus used in several world countries to prevent stump infection by tree pathogenic Heterobasidion fungal species. Previous studies have reported the presence of regional and continental genetic differentiation in host-specific fungi, but the presence of such differentiation for generalist wood saprobes such as P. gigantea has not been often studied or demonstrated. Additionally, little information exists on the distribution of this fungus in western North America. The main purposes of this study were: (I) to assess the presence of P. gigantea in California, (II) to explore the genetic variability of P. gigantea at the intra and inter-continental levels and (III) to analyze the phylogeographic relationships between American and European populations. Seven loci (nrITS, ML5–ML6, ATP6, RPB1, RPB2, GPD and TEF1-α) from 26 isolates of P. gigantea from coniferous forests in diverse geographic distribution and from different hosts were analyzed in this study together with 45 GenBank sequences. One hundred seventy-four new sequences were generated using either universal or specific primers designed in this study. The mitochondrial ML5–ML6 DNA and ATP6 regions were highly conserved and did not show differences between any of the isolates. Conversely, DNA sequences from the ITS, RPB1, RPB2, GPD and TEF1-α loci were variable among samples. Maximum likelihood analysis of GPD and TEF1-α strongly supported the presences of two different subgroups within the species but without congruence or geographic partition, suggesting the presence of retained ancestral polymorphisms. RPB1 and RPB2 sequences separated European isolates from American ones, while the GPD locus separated western North American samples from eastern North American ones. This study reports the presence of P. gigantea in California for the first time using DNA-based confirmation and identifies two older genetically distinct subspecific groups, as well as three genetically differentiated lineages within the species: one from Europe, one from eastern North America and one from California, with the latter presumably including individuals from the rest of western North America. The genetic differentiation identified here among P. gigantea individuals from coniferous forests from different world regions indicates that European isolates of this fungus should not be used in North America (or vice versa), and, likewise, commercially available eastern North American P. gigantea isolates should not be used in western North America forests. The reported lack of host specificity of P. gigantea was documented by the field survey and further reinforces the need to only use local isolates of this biocontrol fungus, given that genetically distinct exotic genotypes of a broad generalist microbe may easily spread and permanently alter the microbial biodiversity of native forest ecosystems.

The effect of exposure to conspecifics on restlessness in the parasitoid wasp Nasonia vitripennis (Hymenoptera: Pteromalidae)

2007 ◽  
Vol 139 (5) ◽  
pp. 678-684 ◽  
Author(s):  
B.H. King
Keyword(s):  
Habitat Quality ◽  
Parasitoid Wasp ◽  
Poor Quality ◽  
The Other ◽  
Dispersal Ability ◽  
Nasonia Vitripennis ◽  
Adult Females ◽  
Selection For ◽  
The Difference ◽  
Abundance And Distribution

AbstractWhen habitat quality is variable, there should be strong selection for the ability to detect and respond to the variation. Adult females of the parasitoid wasp Nasonia vitripennis (Walker) are known to increase their restlessness (the proportion of time in locomotion) both during and after exposure to a poor quality host. Doing so provides a mechanism for leaving a poor host and potentially finding a better host. This study examined whether restlessness also changes in response to competition as indicated by the presence of adult conspecifics. Both restlessness and the probability of dispersing across an inhospitable environment were greater when a female was with another female than when she was alone. However, restlessness did not remain elevated after the other female was removed. In contrast with females, restlessness of males did not increase either during or after exposure to other males, and the probability of dispersing across an inhospitable environment was unaffected by the presence of another male. The difference between females and males may be related to differences in dispersal ability and in the abundance and distribution of hosts versus mates.

scholarly journals Two Cases of Gelsemium Elegans Benth. Poisoning

2007 ◽  
Vol 14 (4) ◽  
pp. 221-224 ◽  
Author(s):  
HT Fung ◽  
KK Lam ◽  
SK Lam ◽  
OF Wong ◽  
CW Kam
Keyword(s):  
Respiratory Failure ◽  
General Public ◽  
The Other ◽  
Respiratory Support ◽  
Close Monitoring ◽  
Morphological Differences

A couple of spouse mistook the Gelsemium elegans Benth. collected in countryside for Mussaenda pubescens Ait. f. and suffered toxicity soon after ingestion. One went into respiratory failure necessitating intubation and the other developed dizziness. The morphological differences between Gelsemium elegans Benth. and Mussaenda pubescens Ait. f. may not be easily recognised by the general public. Close monitoring and respiratory support are the cornerstones of management.

scholarly journals Evaluation of Resistance Development in Bemisia tabaci Genn. (Homoptera: Aleyrodidae) in Cotton against Different Insecticides

Insects ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 996
Author(s):  
Muhammad Zaryab Khalid ◽  
Sohail Ahmed ◽  
Ibrahim Al-ashkar ◽  
Ayman EL Sabagh ◽  
Liyun Liu ◽  
...  
Keyword(s):  
Bemisia Tabaci ◽  
The Other ◽  
Resistance Development ◽  
Susceptible Population ◽  
Low Level ◽  
Development Of Resistance ◽  
Major Pest ◽  
Selection For ◽  
High Level ◽  
Very High

Cotton is a major crop of Pakistan, and Bemisia tabaci (Homoptera: Aleyrodidae) is a major pest of cotton. Due to the unwise and indiscriminate use of insecticides, resistance develops more readily in the whitefly. The present study was conducted to evaluate the resistance development in the whitefly against the different insecticides that are still in use. For this purpose, the whitefly population was selected with five concentrations of each insecticide, for five generations. At G1, compared with the laboratory susceptible population, a very low level of resistance was observed against bifenthrin, cypermethrin, acetamiprid, imidacloprid, thiamethoxam, nitenpyram, chlorfenapyr, and buprofezin with a resistance ratio of 3-fold, 2-fold, 1-fold, 4-fold, 3-fold, 3-fold, 3-fold, and 3-fold, respectively. However, the selection for five generations increased the resistance to a very high level against buprofezin (127-fold), and to a high level against imidacloprid (86-fold) compared with the laboratory susceptible population. While, a moderate level of resistance was observed against cypermethrin (34-fold), thiamethoxam (34-fold), nitenpyram (30-fold), chlorfenapyr (29-fold), and acetamiprid (21-fold). On the other hand, the resistance was low against bifenthrin (18-fold) after selection for five generations. A very low level of resistance against the field population of B. tabaci, at G1, showed that these insecticides are still effective, and thus can be used under the field conditions for the management of B. tabaci. However, the proper rotation of insecticides among different groups can help to reduce the development of resistance against insecticides.

scholarly journals Development of bioactive/active additives based on essential oils: A review

2020 ◽  
Vol 3 (4) ◽  
pp. 60-67
Author(s):  
Jessica Alarcón-Moyano ◽  
◽  
Silvia Matiacevich ◽  
Keyword(s):  
Medicinal Plants ◽  
Essential Oil ◽  
Essential Oils ◽  
Freeze Drying ◽  
The Other ◽  
Wall Material ◽  
Oil Oxidation ◽  
Active Additive ◽  
Wall Materials ◽  
Selection For

The use of bioactive/active additives has been increasing in recent years, especially those derived from medicinal plants such as essential oils. However, due to essential oil oxidation it is necessary to protect it by encapsulation techniques such as: emulsion, spray- and/or freeze-drying as the most economical techniques. On the other hand, an important factor is to determine the appropriate wall material to obtain a prolonged or controlled release in the food or in the organism. Therefore, several factors affect the release of the compounds such as the type, amount of wall material and/or combination of wall materials. Therefore, the knowledge of all the aforementioned factors is important in order to make an adequate selection for the development of a bioactive/active additive based on essential oils.

scholarly journals THIAMINE – INDUCED FORMATION OF THE MONOPYRROLE MOIETY OF PRODIGIOSIN

2007 ◽  
Vol 4 (4) ◽  
pp. 622-627 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Serratia Marcescens ◽  
Yeast Extract ◽  
Type Strain ◽  
The Other ◽  
Red Pigment ◽  
Enhanced Production ◽  
Pyrimidine Moiety ◽  
Glycerol Medium

Thiamine stimulates the production of a red pigment , which is chromatographically and spectrophotometrically identical to prodigiosin , by growing cultures of serratia marcescens mutant 9-3-3 . this mutant is blocked in the formation of 2- methyl -3- amyl pyrorol( MAP),the monopyrrole moiety of prodigiosin , but accumulates 4-methoxy-2, 2-bipyrrole -5- carboxaldehyde (MBC) and can couple this compound with( MAP) to form prodigiosin . Addition of thiamine caused production of( MAP) , and as little as 0.02 mg of thiamine / ml in peptone- glycerol medium stimulated production of measurable amounts of prodigiosin. Phosphate saltes and another type of peptone decreased the thiamine- induced formation of prodigiosin ,yeast extract and glycerol enhanced formation of this substance. Thiamine also enhanced production of prodigiosin by wiled – type Strain Nima of S. marcescens . The pyrimidine moiety of thiamine was also 10% as effective as the vitamin ; the thiazol moiety only 4% , and the two moieties together , 25% . Thiamine did not stimulate production of prodigiosin biosynthesis as strain 9-3-3 . This is not surprising since strain 9-3-3 originated as a result of two mutational events one event may involve thiamine directly , and the other may involve the biosynthesis of( MAP).

Random subset feature selection for ecological niche models of wildfire activity in Western North America

2018 ◽  
Vol 383 ◽  
pp. 52-68 ◽  
Author(s):  
James L. Tracy ◽  
Antonio Trabucco ◽  
A. Michelle Lawing ◽  
J. Tomasz Giermakowski ◽  
Maria Tchakerian ◽  
...  
Keyword(s):  
Feature Selection ◽  
North America ◽  
Ecological Niche ◽  
Western North America ◽  
Ecological Niche Models ◽  
Random Subset ◽  
Selection For ◽  
Niche Models

scholarly journals Inbreeding parents should invest more resources in fewer offspring

2016 ◽  
Author(s):  
A. Bradley Duthie ◽  
Aline M. Lee ◽  
Jane M. Reid
Keyword(s):  
General Theory ◽  
Evolutionary Dynamics ◽  
Inbreeding Avoidance ◽  
The Other ◽  
Trade Off ◽  
Offspring Number ◽  
Focal Female ◽  
Special Cases ◽  
Selection For ◽  
Joint Consideration

AbstractInbreeding increases parent-offspring relatedness and commonly reduces offspring viability, shaping selection on reproductive interactions involving relatives and associated parental investment (PI). Nevertheless, theories predicting selection for inbreeding versus inbreeding avoidance and selection for optimal PI have only been considered separately, precluding prediction of optimal PI and associated reproductive strategy given inbreeding. We unify inbreeding and PI theory, demonstrating that optimal PI increases when a female's inbreeding decreases the viability of her offspring. Inbreeding females should therefore produce fewer offspring due to the fundamental trade-off between offspring number and PI. Accordingly, selection for inbreeding versus inbreeding avoidance changes when females can adjust PI with the degree that they inbreed. In contrast, optimal PI does not depend on whether a focal female is herself inbred. However, inbreeding causes optimal PI to increase given strict monogamy and associated biparental investment compared to female-only investment. Our model implies that understanding evolutionary dynamics of inbreeding strategy, inbreeding depression, and PI requires joint consideration of the expression of each in relation to the other. Overall, we demonstrate that existing PI and inbreeding theories represent special cases of a more general theory, implying that intrinsic links between inbreeding and PI affect evolution of behaviour and intra-familial conflict.

Sign in / Sign up

Export Citation Format

Share Document